Sub-runner structure for concentration detection and concentration detection method thereof

Abstract

The invention relates to a sub-runner structure for concentration detection and a concentration detection method thereof, a plurality of sensors are arranged in sub-runners, the sub-runners and the plurality of sensors form a gas sensor array, and a gas inlet of a detection tube is connected with at least two sub-runners through a tube body; the at least two sub-runners divide the gas at the gas inlet of the detection tube; a first filter membrane, a second filter membrane, a first sensor and a second sensor are arranged in at least two sub-runners, and the first filter membrane and the first sensor form a first component detection structure and are arranged in one sub-runner; the first filter membrane and the first sensor form a first component detection structure, the second filter membrane and the second sensor form a second component detection structure and are arranged in the other sub-runner, and when the initial gas enters the at least two sub-runners, the initial gas is divided into two fluids to respectively pass through the first filter membrane and the second filter membrane and respectively flow to the first sensor and the second sensor; therefore, distinguishing and concentration detection of a plurality of mixed components are realized.

Description

[0001] The original basis of this divisional application is a patent application with the application number 202211661647.X, the application date of December 20, 2022, and the invention name of "Gas identification system and method based on array gas sensor", which claims the priority of a patent application with the application number 202210823256.7, the priority date of July 12, 2022. TECHNICAL FIELD

[0002] The present application relates to the technical field of gas identification, in particular to a shunt structure for concentration detection and a concentration detection method thereof. BACKGROUND

[0003] Combustible gases include but are not limited to natural gas, coal gas, methane, acetylene, hydrogen, carbon monoxide, and vapors of some combustible liquids such as ethanol, methanol, acetone, etc. These gases will explode or burn when they reach a certain concentration in the air and encounter a spark. The city gas pipeline network has many parts set in the city sewer, water well, power trench, and telecom pipeline well, etc. These places often accumulate a large amount of debris, and the debris ferments in the anaerobic environment for a long time to produce biogas of different concentrations, which greatly interferes with gas leakage detection. Therefore, in the gas pipeline network inspection work, the main problem that puzzles the staff is not only to accurately and quickly detect the concentration of methane in natural gas, but also 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 contain ethane. When it is detected that the gas sample contains ethane components, it can be determined that it is gas leaked from the gas pipeline. If no ethane components are 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 not only the size and convenience of the instrument are limited, but also hydrogen needs to be equipped. In order to solve this deficiency, the present application uses several shunts, filters, and sensors to form a combined differential response to measure the concentration of methane and ethane (or other gas components that need to be distinguished) in the target gas to distinguish between biogas and natural gas, thereby avoiding the use of consumable equipment such as hydrogen, making the instrument more convenient to carry and low in maintenance cost.

[0004] CN215415308U discloses a portable combustible gas detector, which comprises a detector main body, the surface of the detector main body is provided with a wire tube, the wire tube adopts a flexible metal wire tube, the upper end surface of the wire tube is provided with a detection probe, the outer surface of the detection probe is connected with a threaded sleeve through threads, the inner side surface of the threaded sleeve is fixedly connected with a square frame, one end of the square frame is fixedly connected with a motor, the driving shaft outer surface of the motor is provided with a fan blade, the lower end surface of the threaded sleeve is provided with an air inlet hole, which is provided with an external air inlet assembly, which can rotate the fan blade through the motor, and can guide air outward, and the airflow can quickly enter through the air inlet hole, can pass through the detection probe for sensing, so as to improve the air intake detection amount, and the detection is sensitive, convenient to use and convenient to carry.

[0005] CN109752344A 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 comprises a shell and a sampling pipe, a methane concentration detection device, a sampling pump, a total hydrocarbon concentration detection device and a control system connected in sequence in the shell. The control system can control the operation of the methane concentration detection device, the sampling pump and the total hydrocarbon concentration detection device. The portable non-methane total hydrocarbon concentration detector of the patent does not need to replace the sample gas used for front and rear detection operations, so that the detection result is not distorted, the detection accuracy is improved, the time consumption caused by the switching of two analyses is reduced, the detection efficiency is improved, and the volume and weight of the instrument are greatly reduced, which can be miniaturized and conveniently carried. However, the above two patents cannot detect the remaining components in the gas to be measured in terms of pertinence, portability and rapidity, which leads to the fact that the personnel cannot quickly and effectively perform the inspection work on the gas pipe network.

[0006] In addition, on the one hand, there are differences in the understanding of those skilled in the art; on the other hand, the inventors have studied a large number of literatures and patents when making the invention, but due to the limited space, all the details and contents are not listed in detail, which does not mean that the invention does not have these characteristics of the prior art, on the contrary, the invention has all the characteristics of the prior art, and the applicant reserves the right to add relevant prior art in the background art. SUMMARY

[0007] The prior art usually detects gas leakage of the gas pipe network by detecting methane, but since part of the city gas pipe network is in an oxygen-deficient environment, different concentrations of biogas may be produced, and the biogas also contains a large amount of methane, so that the staff cannot distinguish the cause of the fault in the gas pipe network. However, the difference between natural gas and biogas is that natural gas also contains ethane. For example, a large amount of gas containing methane but not containing ethane appears in the underground gas pipe network, indicating that biogas is produced under the long-term sedimentation in the underground gas pipe network, rather than leakage of the gas pipe network. On the basis of this, the present application is provided with a plurality of shunt channels, so that the detection tube can judge the plurality of components and concentrations in the gas to be detected, thereby quickly judging and giving the corresponding solution.

[0008] In view of the deficiencies of the prior art, the technical scheme of the present application provides a gas identification system based on an array gas sensor, comprising a detection tube. The detection tube at least comprises a gas sensor array, which is composed of a shunt channel and a plurality of sensors arranged in the shunt channel. The gas inlet of the detection tube is connected to at least two shunt channels through the tube body, so that the gas entering from the gas inlet is shunted into at least two streams. At least two shunt channels are provided with filter membranes and sensors based on a plurality of mixed components in the gas to realize the differentiation and concentration detection of the plurality of mixed components. Through the above method, the cause of the target gas can be distinguished, i.e. the target gas appears due to a certain fault in the gas pipe network. For example, a large amount of gas containing methane but not containing ethane appears in the underground gas pipe network, indicating that biogas is produced under the long-term sedimentation in the underground gas pipe network, rather than leakage of the gas pipe network. This rapid judgment method not only enables the gas pipe network dispatching center to select different safety plans according to the actual fault type, but also enables each component in the gas to be detected and determined in detail, thereby recording the gas changes of the entire city gas pipe network as a whole, preventing the accumulation of flammable gas, and ensuring safety. The present application measures each gas component in the target gas by the combination of a plurality of shunt channels, filter membranes and sensors, which not only serves for the inspection of the gas pipe network in normal times, but also can effectively detect dangerous environments such as sewage treatment plants, septic tanks, chemical enterprises, gas stations and dangerous goods warehouses, thereby preventing accidents and providing technical basis for accident handling.

[0009] According to a preferred embodiment, the shunt channel has a streamline structure to enable the gas to flow smoothly along the streamline structure, and the gas flow direction is fixed to enter the gas sensor array from the gas inlet, thereby increasing the gas detection amount.

[0010] According to a preferred embodiment, the at least two branch channels are connected into a single channel after the gas is branched at the gas inlet of the detection tube and after the filtered membrane and the sensor, so that the at least two streams of fluid are merged to concentrate the detected gas and discharge the gas out of the detection tube. The merging of the at least two streams of fluid can hinder the reverse flow of the gas along the detection tube. In this way, the gas to be detected is independently divided into two parts, and the components are detected respectively, so as to obtain the component types and concentrations in the gas to be detected.

[0011] According to a preferred embodiment, the branch channel comprises a branching end and a merging end, the branching end is an end that contacts the gas and branches the gas, and the merging end is an end that the gas leaves the branch channel and merges. The radius of curvature of the merging end is greater than the radius of curvature of the branching end. The branch channel not only provides a space for the branched gas to be detected respectively, but also forms a plurality of pressure zones for the gas flow path, so that the target gas flows out of the gas outlet by the resistance generated by the change of pressure difference, and the remaining gas is prevented from flowing into the gas outlet to interfere with the detection of the target gas, thereby ensuring the accuracy of the detection. The radius of curvature of the merging end is greater than the radius of curvature of the branching end, so that the gas overflowing from the gas outlet is reduced in power. The gas is separated by the plurality of pressure zones in the branch channel, so that the flow process of the gas is hindered under the action of the pressure gradient. The arrangement of the branch channel is beneficial to the unidirectional flow performance of the target gas. The branch channel blocks the reverse flow of the gas, and functions as a unidirectional valve for the gas flow. For example, when the gas has a reverse flow trend, the reverse gas is squeezed and hindered at the merging end due to the radius of curvature of the merging end being greater than the radius of curvature of the branching end, and even forms a vortex, so that the reverse gas cannot flow, and the reverse gas is prevented from flowing to the sensor, thereby reducing the accuracy of the concentration detection and even causing misjudgment.

[0012] According to a preferred embodiment, before the gas enters the branch channel, the detection tube is provided with at least a basic sensor for detecting the initial gas to obtain a basic response of the gas, and a gas pump is arranged after the first sensor to pump the initial gas. The gas pump can make the gas to be detected enter the detection tube under the pumping action, and can accelerate the flow rate of the gas in the detection tube, thereby forming a pressure difference to force the gas to enter the plurality of branch channels better.

[0013] According to a preferred embodiment, the at least two branch channels are provided with a first filter membrane, a second filter membrane, a first sensor and a second sensor, wherein the first filter membrane and the first sensor are arranged in one branch channel as a group, and the second filter membrane and the second sensor are arranged in another branch channel as a group. When the initial gas enters the at least two branch channels, the initial gas is branched into two streams of fluid to pass through the first filter membrane and the second filter membrane respectively, and flow to the first sensor and the second sensor respectively.

[0014] According to a preferred embodiment, the first filter membrane and / or the second filter membrane are based on the principle of homomiscibility to filter interfering gases present in the gas, so that the target gas 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 gases are at least composed of ethanol and / or water, and the target gas at least includes methane or ethane.

[0015] According to a preferred embodiment, the first sensor and the second sensor respectively obtain a first response and a second response based on the target gas, and the first response and the second response are subjected to a differential response comparison with the base response to calculate the type and concentration of each component in the gas.

[0016] According to a preferred embodiment, the probe pipe is provided with a gas outlet for discharging the gas, and the gas outlet is arranged at the end of the gas sensor array along the gas flow direction.

[0017] The present application also relates to a gas identification method based on an array gas sensor, wherein the probe pipe at least includes a gas sensor array, and the gas sensor array is composed of a plurality of shunt channels and a plurality of sensors, and the plurality of sensors are arranged in the shunt channels. The method at least includes: the gas inlet of the probe pipe is connected to the at least two shunt channels through the pipe body, so that the gas entering from the gas inlet is shunted into at least two streams. The at least two shunt channels are provided with filter membranes and sensors based on a plurality of mixed components in the gas to achieve the differentiation and concentration detection of the plurality of mixed components.

[0018] The beneficial technical effects of the present application are:

[0019] (1) The design scheme of the plurality of shunt channels, filter membranes and sensors of the present application can distinguish the cause of the target gas, i.e. the target gas due to a fault in the gas pipe network. For example, a large amount of gas containing methane but not containing ethane appears in the underground gas pipe network, which indicates that marsh gas is generated under the long-term sedimentation in the underground gas pipe network, rather than a leakage in the gas pipe network. This rapid judgment method not only enables the gas pipe network dispatching center to select different safety plans according to the actual fault type, but also enables the components in the gas to be detected and determined in detail, so as to record the gas changes in the entire city gas pipe network, prevent the accumulation of flammable gas, and ensure safety. The present application measures each gas component in the target gas through the combination differential response of the plurality of shunt channels, filter membranes and sensors, which is not only used for the routine inspection of the gas pipe network, but also can effectively detect dangerous environments such as sewage treatment plants, septic tanks, chemical enterprises, gas stations and dangerous goods warehouses, so as to prevent accidents and provide technical basis for accident handling.

[0020] (2) The shunt channel not only provides a space for detecting the gas separately after the gas is shunted, but also forms multiple pressure zones for the gas flow path, generates resistance by the change of pressure difference, and makes the target gas flow out of the gas outlet, preventing the remaining gas from flowing into the gas outlet and interfering with the detection of the target gas, thereby ensuring the accuracy of the detection. The curvature radius of the confluence end is greater than that of the shunt end, so that the gas overflowing from the gas outlet is reduced in power, and the gas is separated by multiple pressure zones in the shunt channel, so that the flow process of the gas is hindered under the action of the pressure gradient. The shunt channel is beneficial to the unidirectional flow performance of the target gas. The shunt channel blocks the reverse flow of the gas, and functions as a unidirectional valve for gas flow. For example, when the gas has a reverse flow trend, the reverse gas is squeezed and hindered at the confluence end due to the curvature radius of the confluence end being greater than that of the shunt end, and even forms a vortex, so that the reverse gas cannot flow, preventing the reverse gas from flowing to the sensor and causing the accuracy of the concentration detection to decrease, and even causing misjudgment. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic diagram of a preferred embodiment of the detection tube of the present application;

[0022] Figure 2 is a module flow chart of a preferred embodiment of a gas identification system based on an array gas sensor of the present application;

[0023] Figure 3 is a structural schematic diagram of a preferred embodiment of a gas sensor array of the present application;

[0024] Figure 4 is a structural schematic diagram of another preferred embodiment of a gas sensor array of the present application.

[0025] LIST OF REFERENCE NUMERALS

[0026] 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: gas outlet; 108: third sensor; 109: fourth sensor; 110: branch channel. DETAILED DESCRIPTION

[0027] The following will be described in detail with reference to the drawings.

[0028] Example 1

[0029] The present application relates to a gas identification system based on an array gas sensor, which comprises a detection tube 1. As shown in Figure 1As shown, the detection tube 1 at least comprises a gas sensor array 2, which is composed of a plurality of shunt channels 3 and a plurality of sensors arranged in the shunt channels 3. The gas inlet of the detection tube 1 is connected to at least two shunt channels 3 through the tube body, so that the gas entering from the gas inlet is shunted into at least two streams. At least two shunt channels 3 are provided with filter membranes and sensors based on a plurality of mixed components in the gas to realize the differentiation and concentration detection of the plurality of mixed components. A plurality of shunt channels 3 are arranged to divide the inside of the detection tube 1 into a plurality of detection spaces, and the target gas is detected in parallel to detect different types of components (such as methane and ethane) contained in the target gas. Through the above method, the cause of the target gas can be distinguished, that is, the target gas appears due to a fault in the gas pipe network. For example, a large amount of gas containing methane but not containing ethane appears in the underground gas pipe network, which indicates that biogas is generated under the long-term sedimentation in the underground gas pipe network, rather than a leakage in the gas pipe network. This rapid judgment method not only enables the gas pipe network dispatching center to select different safety plans according to the actual fault type, but also enables the components in the gas to be detected and determined in detail, thereby recording the gas changes in the entire city gas pipe network, preventing the accumulation of flammable gas, and ensuring safety. The present application measures each gas component in the target gas through the combination of a plurality of shunt channels 3, filter membranes and sensors, which is not only used for the inspection of the gas pipe network in normal times, but also can effectively detect dangerous environments such as sewage treatment plants, septic tanks, chemical enterprises, gas stations and dangerous goods warehouses, so as to prevent accidents and provide technical basis for accident handling.

[0030] According to a preferred embodiment, the shunt channel 3 has a streamlined structure to make the gas flow smoothly along the streamlined structure, and the direction of the gas flow is fixed to enter the gas sensor array 2 from the gas inlet, thereby increasing the gas detection amount.

[0031] According to a preferred embodiment, at least two shunt channels 3 are connected to a single channel after the gas is shunted at the gas inlet of the detection tube 1 and passes through the filter membrane and the sensor, so that at least two streams converge, thereby concentrating the detected gas out of the detection tube 1. The convergence process of the at least two streams can hinder the reverse flow of the gas along the detection tube 1. In this way, the to-be-detected gas is independently divided into two parts, and the components are detected respectively, so as to obtain the component types and concentrations in the to-be-detected gas.

[0032] According to a preferred embodiment, the shunt channel 3 comprises a shunt end and a converging end, the shunt end being an end that contacts the gas and shunts the gas, and the converging end being an end that converges the gas out of the shunt channel 3; wherein the radius of curvature of the converging end is greater than the radius of curvature of the shunt end. The shunt channel 3 not only provides a space for the shunted gas to be detected separately, but also forms a plurality of pressure zones for the gas flow path, so that the target gas flows out of the gas outlet 107 by the change of pressure difference to generate resistance, and the remaining gas is prevented from flowing into the gas outlet 107 to interfere with the detection of the target gas, thereby ensuring the accuracy of the detection. The radius of curvature of the converging end is greater than the radius of curvature of the shunt end, so that the gas overflowing from the gas outlet 107 is reduced in power, and the gas is separated by the plurality of pressure zones in the shunt channel 3, so that the gas flow is hindered under the action of the pressure gradient. The shunt channel 3 is beneficial to the unidirectional flow performance of the target gas. The radius of curvature of the shunt end is between 0.2 and 0.5 cm. The radius of curvature of the converging end is between 0.5 and 1 cm. Too large or too small radius of curvature will cause different inlet and outlet pressure drops when the gas flows into the shunt channel 3, which will cause the gas flow to be unstable. The shunt channel 3 blocks the reverse flow of the gas, and functions as a unidirectional valve for the gas flow. For example, when the gas has a reverse flow trend, the reverse gas is squeezed and hindered at the converging end due to the larger radius of curvature of the converging end than that of the shunt end, and even forms a vortex, so that the reverse gas cannot flow, preventing the reverse gas from flowing to the sensor and causing the concentration detection accuracy to decrease, and even causing misjudgment.

[0033] According to a preferred embodiment, before the gas enters the shunt channel 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, and a gas pump 102 is arranged after the basic sensor 101 for pumping the initial gas. The gas pump 102 can make the gas to be detected enter the detection tube 1 under the action of the pump, and can accelerate the flow rate of the gas in the detection tube 1, thereby forming a pressure difference to force the gas to enter the plurality of shunt channels 3 better.

[0034] According to a preferred embodiment, the first filter membrane 105, the second filter membrane 106, the first sensor 103 and the second sensor 104 are arranged in the at least two branch channels 3, wherein the first filter membrane 105 and the first sensor 103 are arranged in one branch channel 3 as a group, and the second filter membrane 106 and the second sensor 104 are arranged in another branch channel 3 as a group. When the initial gas enters the at least two branch channels 3, the initial gas is branched into two streams 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 arranged as a methane sensor array, for example, a metal oxide base. The 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 the basic sensor 101, the first sensor 103 and the second sensor 104, wherein the basic sensor 101 is a far-end sensor, and the first sensor 103 and the second sensor 104 are near-end sensors, and the first filter membrane 105 and the second filter membrane 106 are dehumidifying membranes or VOC filter membranes. The difference between the responses of the first sensor 103 and the second sensor 104 and the basic sensor 101 is used to determine the type and concentration of the gas, and the air pump 102 can use a pump suction assembly to accelerate the flow rate of the gas. The first filter membrane 105 and the second filter membrane 106 are porous polar filter cotton (dehumidifying membranes or VOC filter membranes), according to the principle of "like dissolves like", and polar molecules are easily dissolved in polar solvents, and non-polar molecules are easily dissolved in non-polar solvents. The first filter membrane 105 and the second filter membrane 106 can use polar filter membranes, including PTFE membranes, to filter interfering gases such as ethanol and humidity, so as to ensure that the target gas is not affected. It should be noted that the application proposes the first filter membrane 105 and the second filter membrane 106 based on the principle of "like dissolves like" for the required functions in specific embodiments, but it does not mean that the application does not include other required principles that achieve the same effect. Various other solutions can be thought of under the inspiration of the corresponding functions of the application, and these solutions also belong to the disclosure range of the application and fall within the protection scope of the application.

[0035] 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 measured gas 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 gas is at least composed of ethanol and / or water, and the measured gas at least includes methane or ethane.

[0036] 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 measured gas, and the first response and the second response are compared with the basic response in a differential response to calculate the type and concentration of each component in the gas.

[0037] According to a preferred embodiment, the probe tube 1 is provided with a gas outlet 107 for discharging the gas, which is arranged at the end of the gas sensor array 2 along the gas flow direction.

[0038] According to a preferred embodiment, the part of the shunt channel 3 after the first sensor 103 and the second sensor 104 can be provided with a branch channel 110 for changing the pressure at the confluence end of the shunt channel 3. The gas after being detected by the first sensor 103 and the second sensor 104 needs to be discharged from the gas outlet 107 to avoid accumulation in the shunt channel 3, which affects the next detection. The curvature radius of the confluence end of the present application is arranged to discharge the gas in the shunt channel 3 as soon as possible, and the discharge way is to form a pressure difference to accelerate the gas flow rate, so that the gas is discharged from the gas outlet 107. However, the defect of this way is that the too fast gas flow rate will cause the pressure difference to increase, so that the first sensor 103 and the second sensor 104 are squeezed in the shunt channel 3, and even cause the shunt channel 3 to deform and break. For this, the present application is provided with a branch channel 110 at the confluence end. As shown in Figure 3 The plurality of branch channels 110 can be arc-shaped, Y-shaped, trapezoidal, or other shapes according to needs. The diameter of the branch channel 110 is one third to one ninth of the diameter of the shunt channel 3. 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 gas outlet 107 faster, and the gas pressure in the shunt channel 3 is reduced to prevent the shunt channel 3 from deforming and breaking, and to increase the service life of the shunt channel 3.

[0039] According to a preferred embodiment, the first sensor 103 and the second sensor 104 can be arranged at the connection point of the shunt end and the confluence end. Since the curvature radius of the shunt end is small, when the gas reaches the connection point, the flow rate of the gas reaches the lowest point, and arranging the sensor at the lowest point of the gas flow rate is beneficial to improve the accuracy of the gas component detection. Preferably, a third sensor 108 and a fourth sensor 109 can also be arranged at the entrance of the shunt end of the shunt channel 3. Figure 4As shown, the flow rate of the gas at the entrance of the shunt end of the shunt passage 3 is not weakened by the pressure difference, that is, the gas still maintains the maximum flow rate without being hindered by the curvature radius of the shunt end. At this point, the third sensor 108 and the fourth sensor 109 are arranged to serve as a control group of the first sensor 103 and the second sensor 104. By detecting the concentration of the gas at different flow rates, the control group data is obtained. The data can be used to determine whether the first sensor 103 and the second sensor 104 have a detection failure. That is, the gas data detected by the first sensor 103 and the second sensor 104 should be consistent with the gas data detected by the third sensor 108 and the fourth sensor 109, or within the error tolerance 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 accelerated to detect the gas at different flow rates and determine whether there is a detection failure caused by too low gas flow rate or blockage. The acceleration of the gas flow rate can be achieved by increasing the power of the gas pump 102. After the initial flow rate of the gas is increased, the flow rate entering the shunt passage 3 is increased, 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.

[0040] According to a preferred embodiment, the plurality of sensors are also arranged to calibrate the detected gas composition and concentration data. For example, when only part of the methane in the gas pipe network leaks out, it is possible that only a single sensor or not all sensors detect that the gas contains methane, while the remaining sensors do not detect that the gas contains methane. In this case, the master control unit 5 re-collects and detects the gas through the plurality of sensors to calibrate the methane concentration or warning detected at the previous time to prevent false detection. If the sensor also detects methane, it is determined that the methane concentration or warning at the previous time is the initial time. If the sensor does not detect methane, it is determined that the methane concentration or warning at the previous time is false. During the second detection process, after the sensor detects methane, the master control unit 5 records the detection time point and the detected concentration of each sensor in the time axis. The methane time point detected at the previous time is set as the initial time, and the methane concentration detected at the previous time is the initial concentration, so that the master control unit 5 not only issues a warning for the methane leakage, but also issues a corresponding warning for the concentration change of the methane and the time change of the methane leakage in combination with the time axis, and provides it to the gas pipe network dispatching center to enable the gas pipe network dispatching center to make targeted deployment and propose corresponding solutions. Preferably, the power circuit supplies power to the master control unit 5. Alternatively, the power circuit charges the battery assembly, and the battery assembly supplies power to the master control unit 5.

[0041] According to a preferred embodiment, the main control unit 5 can control the detection frequency of each sensor according to the gas flow rate in the shunt channel 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 adopt cross-detection mode to cover the detection of the measured gas. The purpose of such arrangement is that the multi-time point cover detection can reduce the invalid data measured by multiple sensors, and the cross-detection mode can cover the time axis so that the main control unit 5 can monitor the real-time data of the gas pipe network and transmit it to the gas pipe network dispatching center. The cover detection mode makes the detection data of the gas pipe network perfect, and the detection times of a single sensor are detected, thereby extending the service life of the sensor. The prior art often uses a single resistance sensor measurement method to detect methane concentration, but in the inspection work, the sensor needs to be used frequently to undertake a large amount of detection work. The high frequency of use leads to high time and low efficiency of the sensor, resulting in short service life. The cover cross-detection mode adopted by the present application can effectively solve the problem of short service life of the sensor, and the mode reduces the collection of invalid data, and can also cover the detection time axis, which is low in cost and improves the detection accuracy and detection efficiency. 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 improvement can be adaptively adjusted according to needs, and details are not repeated. The present application also relates to a gas identification method based on an array gas sensor, wherein the detection pipe 1 at least comprises a gas sensor array 2, and the gas sensor array 2 is composed of a shunt channel 3 and a plurality of sensors. In the case that the plurality of sensors are arranged in the shunt channel 3, the method at least comprises: the gas inlet of the detection pipe 1 is connected to at least two shunt channels 3 through the pipe body, so that the gas entering from the gas inlet is shunted into at least two streams. At least two shunt channels 3 are provided with filter membranes and sensors based on a plurality of mixed components in the gas to realize the differentiation and concentration detection of the plurality of mixed components.

[0042] Embodiment 2

[0043] This embodiment is further and / or supplementary to the above embodiments, and repeated contents are not described again.

[0044] According to a preferred embodiment, the comparison of the differential responses is at least performed by the processing module. For example, the processing module is configured to compare the differential responses of the first sensor 103 and the second sensor 104, and the differential responses of the third sensor 108 and the fourth sensor 109. Figure 2As shown, the gas sensor array 2 sends the measured gas component concentration to the signal processing circuit 4 of the processing module by A / D sampling, and the signal processing circuit 4 is connected to the master control unit 5. The master control unit 5 judges the type of gas and whether the methane and / or ethane gas concentration in the gas exceeds the safety threshold by comparing the difference between the first response and the second response with the base response. Since the filter membrane is arranged between the sensors, the differential response characteristics of the sensors can reflect the type of gas.

[0045] According to a preferred embodiment, the differential response judgment process for methane is as follows: when the data disturbance causes the response of the base sensor 101 and the first sensor 103 to be th, th is the response value of the sensor, reflecting the size of the detection signal of the sensor. When the base 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, but does not contain methane gas; when the base response is greater than th, the first response is greater than th, and the base 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 whether it exceeds the safety threshold is judged; when the base response is greater than th, the first response is greater than th, and the base response is greater than 1.2-5 times the first response, then the gas contains non-polar interference gas. Assuming that the data disturbance causes the response to be th. When the base response is greater than th, and the first response is less than th, the target gas is high-humidity water molecules or other polar molecules blocked by the filter membrane, and the processing module does not perform the concentration conversion algorithm to judge the methane gas concentration; the base response is greater than th, the first response is greater than th, and (1.2-5) times the first response is greater than the base response, which is greater than 0.8 times the first response, the target gas contains methane gas, and the methane gas concentration is judged according to the concentration conversion algorithm, and whether it exceeds the safety threshold is judged to determine whether to alarm; the base response is greater than th, the first response is greater than th, and the base response is greater than (1.2-5) times the first response, the target gas still contains non-polar interference gas, and the ratio of the base response to the first response is calculated according to the machine learning algorithm to calculate the types and concentrations of various mixed gases. Similarly, the differential response process for ethane can be performed by replacing different filter membranes and sensors, which will not be described here. It can be understood that for the remaining gas components that need to be detected, the same can be achieved by replacing the filter membrane and the sensor. In the present application, the first filter membrane 105 and the first sensor 103 can be configured as a first component detection structure for detecting the methane component in the gas, and the second filter membrane 106 and the second sensor 104 can be configured as a second component detection structure for detecting the ethane component in the gas. The gas is split at the split end, so that the gas entering the first component detection structure and the second component detection mechanism is the same, and there is no detection error. If the sensor is placed in the same gas flow channel at the same time, the measured components and concentrations will be affected by each other, and the interference gas affecting the detection of methane is different from the interference gas affecting the detection of ethane, and different filter membranes (i.e. the first filter membrane 105 and the second filter membrane 106) are required to filter them respectively. If only one gas flow channel is provided, the detection of methane and ethane will be affected by the interference gas, resulting in reduced detection accuracy, and even false detection. Therefore, the present application provides a plurality of split channels 3 and different component detection structures therein to separate the components and concentrations in the gas to be detected. It should be noted that the above base response refers to the sensor response threshold value caused by the methane concentration that needs to be alarmed.The above 1.2-5 is a range showing the required response for the specific embodiments of the present application, and does not represent a range that does not include the remaining required responses that achieve the same effect.

[0046] The prior art for the detection of flammable gas generally uses a catalytic type flammable gas detector, mainly using the heat effect principle of catalytic combustion. The sensor in the catalytic type flammable gas detector can measure the gas by using the resistance change of the heated refractory metal platinum wire under certain temperature conditions. However, the defects of the prior art are that the combustion values of different gases are different, the sensor measures the resistance change caused by combustion rather than the concentration change, so the readings of different gases may be different even at the same concentration. It has no selectivity within the gas range, and the sensor is easily affected by the compounds in the gas, resulting in reduced service life. The detector also has many shortcomings such as high working temperature, inability to use in anoxic environment, etc.

[0047] Unlike the prior art which detects by resistance change, the present application adopts a combination of several shunt channels 3, filter membranes and sensor differential response mode, which quantitatively measures the response value of the gas in the sensor by differential comparison, and the response value is proportional to the concentration of the components, so as to obtain the concentration of each gas component 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 concentration measured by the combustion value is disturbed by the mixed gas, so that the detector has no selectivity, and the detection method will not generate heat to cause the service life of the detector to decrease. The portable way makes the device can be used in various complex environments. For example, when inspecting the underground gas pipeline network of the city, the oxygen content is low in a narrow environment, which causes the problem of not being able to burn. The detection method not only detects the methane leaked by the gas pipeline network, but also detects the remaining gas components by setting different filter membranes and sensors, such as detecting ethane, so as to distinguish the various mixed components in the target gas.

[0048] The prior art for detecting gas leakage of the gas pipeline network generally uses the method of detecting methane, but since part of the city gas pipeline network is in anoxic environment, different concentrations of biogas may be produced, and biogas also contains a large amount of methane, so that the workers cannot distinguish the cause of the fault in the gas pipeline network. However, the difference between natural gas and biogas is that natural gas also contains ethane components. For example, a large amount of gas containing methane but not containing ethane appears in the underground gas pipeline network, indicating that biogas is produced under the long-term sedimentation effect in the underground gas pipeline network, rather than leakage of the gas pipeline network. On this basis, the present application provides several shunt channels 3, so that the detection tube 1 can judge the various components and concentrations in the gas to be measured, so as to quickly judge and give the corresponding solution.

[0049] According to a preferred embodiment, as shown in Figure 2 The processing module is also provided with a communication interface circuit 6 for connecting with the smart device, so that the host unit 5 interacts with the smart device. The data interaction includes sensor calibration, sensor fault self-checking and methane concentration data storage, etc., to realize real-time recording and intelligent alarm through the smart device. As shown in Figure 2 The battery assembly charges the smart device.

[0050] According to a preferred embodiment, the detection tube 1 and the gas sensor array 2 of the present application can be connected to a mobile phone through a mobile phone charging port for charging or data transmission, realizing portable outdoor gas pipe 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 application also includes an alarm instrument, which includes the following functions: data storage function, alarm function, battery under-voltage prompt, wireless communication mode and sampling probe. The alarm instrument can also use a mobile phone module to realize sensor calibration, sensor fault self-checking and intelligent alarm function. The communication mode of the alarm instrument: through the mobile phone (such as Type-C port) through the protocol for data transmission; through the Bluetooth module for communication, cooperating with the mobile phone program or WeChat applet for data transmission. The alarm instrument can be developed and set through the 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 MongoDB, SQL and Oracle tools. The positioning function of the alarm instrument can be used for GPS positioning, realizing inspection live, real-time track, track playback, device power management, pipeline management, pipe network drawing, third-party monitoring, device management, account management and attendance photographing, etc.

[0051] Example 3

[0052] This embodiment is a further and / or supplement to the above-mentioned embodiments, and the repeated contents will not be described again.

[0053] According to a preferred embodiment, the detection tube 1 is a single tube and is internally provided with a methane sensor array, for example, a metal oxide-based, which removes the influence of humidity, ethanol and other interfering gases.

[0054] According to a preferred embodiment, the detection tube 1 is a single tube and is internally provided with a basic sensor 101, a first sensor 103 and a second sensor 104, which are far and near, respectively, and are separated by a first filter membrane 105 and a second filter membrane 106, for example, a dehumidifying membrane or a VOC filter membrane, to determine the gas type and concentration by using the differential response of the three sensors. A pump 102 can be used at the tail end to accelerate the gas flow rate.

[0055] According to a preferred embodiment, the 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.

[0056] According to a preferred embodiment, the detection tube 1 is a single tube, which is internally provided with a methane sensor array and a chromatographic column, and the methane sensor is located at the tail end of the chromatographic column. The chromatographic column can separate different gases according to the boiling point, polarity and adsorption performance of the flowing components, or determine the type of gas by the time of gas flow.

[0057] According to a preferred embodiment, the detection tube 1 is a single tube, which is internally provided with a far-two-close basic sensor 101, a first sensor 103 and a second sensor 104, and a chromatographic column. 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 tail end of the chromatographic column. The first sensor 103 and the second sensor 104 further determine the type of gas.

[0058] According to a preferred embodiment, the detection tube 1 is a three-section single tube, which is internally provided with a far-two-close basic sensor 101, a first sensor 103 and a second sensor 104. The first section is internally provided with the basic sensor 101, the third section is internally provided with the first sensor 103 and the second sensor 104, and the second section is a first filter membrane 105 and a second filter membrane 106. The second section is a consumable. According to the response of the basic sensor 101, the first sensor 103 and the second sensor 104, it is determined whether the second section needs to be replaced. The three-section detection tube 1 is connected by threads. When the second section tube containing the filter membrane has a problem, the threads are turned off for replacement. Specifically, when the first section internal basic sensor 101 has a response, but the first sensor 103 and / or the second sensor 104 have no response, the device gives an alarm signal, and the second section tube needs to be replaced. Alternatively, an alcohol gas test can be performed, and the device working mode is changed to test mode. When the test results show that the basic sensor 101, the first sensor 103 and the second sensor 104 all have responses, the test indicates that the second section tube needs to be replaced.

[0059] Throughout the specification, the features introduced by "preferably" are only optional, and should not be understood as necessarily provided. Therefore, the applicant reserves the right to abandon or delete the relevant preferred features at any time.

[0060] It should be noted that the above specific embodiments are exemplary, and those skilled in the art can think of various solutions inspired by the disclosure of the present application, and these solutions also belong to the disclosed scope of the present application and fall within the protection scope of the present application. Those skilled in the art should understand that the specification and drawings of the present application are illustrative and do not constitute a limitation on the claims. The protection scope of the present application is defined by the claims and their equivalents.

Claims

1. A split flow path structure for concentration detection, characterized by, A plurality of sensors are arranged in the shunt channels (3), and the shunt channels (3) and the plurality of sensors form a gas sensor array (2), The gas inlet of the detection tube (1) is connected to at least two shunt channels (3) through the tube body, and the at least two shunt channels (3) shunt the gas at the gas inlet of the detection tube (1); At least two shunt channels (3) are provided with a first filter membrane (105), a second filter membrane (106), a first sensor (103) and a second sensor (104), wherein 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), When the initial gas enters the at least two shunt channels (3), the initial gas is shunted into two streams to pass through the first filter membrane (105) and the second filter membrane (106) respectively, and flows to the first sensor (103) and the second sensor (104) respectively, so as to realize the differentiation and concentration detection of a plurality of mixed components.

2. The flow channel structure according to claim 1, wherein The first filter membrane (105) and / or the second filter membrane (106) are based on the principle of homomiscibility to filter interfering gases present in the gas, so that the to-be-detected gas in the gas passes through the first filter membrane (105) and / or the second filter membrane (106) in the at least two shunt channels (3) to reach the first sensor (103) and / or the second sensor (104).

3. The flow channel structure according to claim 1 or 2, wherein The gas sensor array (2) sends the measured gas component concentration to the signal processing circuit (4) of the processing module through A / D sampling, and the signal processing circuit (4) is connected to the main control unit (5); The main control unit (5) compares the difference between the first response and the second response with the base response to determine the type of gas and whether the concentration of methane and / or ethane gas in the gas exceeds the safety threshold.

4. The flow conduit structure according to any one of claims 1 to 3, wherein The shunt channel (3) includes a shunt end and a confluence end, the shunt end is an end that contacts the gas and shunts the gas, and the confluence end is an end that the gas leaves the shunt channel (3) and converges, and the convergence process of the at least two streams can hinder the reverse flow of the gas along the detection tube (1).

5. The flow conduit structure according to any one of claims 1 to 4, wherein The detection tube (1) is provided with a gas outlet (107) for discharging the gas, and the gas outlet (107) is arranged at the end of the gas sensor array (2) in the gas flow direction.

6. The shunt channel structure according to any one of claims 1 to 5, wherein, The curvature radius of the confluence end of the at least two shunt channels (3) is greater than that of the shunt end, so as to form a plurality of pressure zones for the gas flow path, and the resistance is generated by the change of pressure difference to make the target gas flow out of the gas outlet (107); Wherein, the reverse gas is squeezed and hindered at the confluence end, and even forms a vortex, so that the reverse gas cannot flow.

7. The flow conduit structure of any one of claims 1 to 6, wherein The curvature radius of the shunt end of the shunt channel (3) is between 0.2 and 0.5 cm; The curvature radius of the confluence end of the shunt channel (3) is between 0.5 and 1 cm.

8. The flow conduit structure of any one of claims 1 to 7, wherein The part of the shunt channel (3) after the first sensor (103) and the second sensor (104) is provided with a branch channel (110) for changing the pressure of the confluence end of the shunt channel (3); The branch channel (110) is used for changing the pressure difference of the shunt channel (3), so that the gas can flow out of the gas outlet (107) more quickly, and the gas pressure in the shunt channel (3) is reduced.

9. The flow conduit structure of any one of claims 1 to 8, wherein, The diameter of the branch channel (110) is one third to one ninth of the diameter of the shunt channel (3).

10. A concentration detection method for a concentration detection flow path structure, characterized by, The method comprises: The gas inlet of the detection tube (1) is connected with at least two shunt channels (3) through the tube body, and the at least two shunt channels (3) shunt the gas at the gas inlet of the detection tube (1); When the initial gas enters the at least two shunt channels (3), the initial gas is shunted into two flows 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, so as to realize the differentiation and concentration detection of several mixed components; Wherein, a plurality of sensors are arranged in the shunt channel (3), and the shunt channel (3) and the plurality of sensors constitute a gas sensor array (2), The first filter membrane (105), the second filter membrane (106), the first sensor (103) and the second sensor (104) are arranged in the at least two shunt channels (3), wherein 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).

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