Flexible probe based limited space toxic gas gradient detection system and method

Abstract

A limited space toxic gas gradient detection system and method based on a telescopic probe rod, the system comprising: an electric telescopic rod including a telescopic assembly, a cross bracket and an electric drive mechanism, the telescopic assembly including a main rod body, a first telescopic rod and a second telescopic rod; the electric drive mechanism being installed inside the main rod body and used to drive the second and first telescopic rods to extend and retract along the axial direction; the cross bracket being installed at the end of the second telescopic rod, and a plurality of integrated sensor modules being installed at the lower end of the cross bracket at intervals; the method comprising: detecting different detection planes in stages according to the extension step distance, sending the obtained detection data to a data processing terminal, generating a three-dimensional gas concentration distribution model based on the detection data by the data processing terminal, and generating an accurate vertical gradient distribution map in combination with an obstacle coordinate constraint condition. The system and method can automatically realize high-precision gradient detection of toxic gas in the vertical direction in a limited space.

Description

Technical Field

[0001] This invention belongs to the field of intelligent detection technology of toxic gases, specifically a toxic gas gradient detection system and method in a confined space based on a retractable probe. Background Technology

[0002] In industries such as manufacturing, chemical engineering, and municipal engineering, confined spaces with complex working environments and poor ventilation are frequently encountered. These confined spaces are prone to accumulating toxic and harmful gases, especially hydrogen sulfide. Due to its high density, hydrogen sulfide gas tends to accumulate at the bottom of the confined space, forming a concentration gradient from top to bottom. In recent years, hydrogen sulfide poisoning accidents have occurred frequently, mainly because workers only perform single-point sampling at the entrance or shallow level before entering the confined space, ignoring the gradient changes in hydrogen sulfide concentration and thus failing to accurately assess the risk of deep, high-concentration areas. Existing gas detection devices are mostly handheld single-point measuring devices, lacking the ability to continuously detect vertically within the space. Furthermore, manual sampling in high-risk areas is inefficient and poses significant safety risks. Current technologies cannot construct gas concentration gradient distribution models or delineate safe work zones based on real-time data, severely restricting the safety assurance capabilities for confined space operations.

[0003] Traditional methods for detecting toxic gases in confined spaces primarily rely on handheld, single-point sampling devices, which cannot simultaneously acquire vertical gas concentration gradient data, leading to misjudgments of high-risk areas by operators. While some existing technologies have proposed improvements, significant shortcomings remain. For example, while existing insertable detectors offer telescopic capabilities, they lack multi-dimensional scanning and do not integrate a spatial modeling module; existing probe protection mechanisms optimize equipment safety but fail to address the need for high-precision vertical gradient detection; and existing ventilation detection systems, while offering automated control, suffer from fixed sensor layouts that are ill-suited to complex spatial conditions. These deficiencies make it difficult for current equipment to accurately identify vertical concentration gradient changes of toxic gases such as hydrogen sulfide and oxygen within confined spaces, easily leading to misjudgments of poisoning and asphyxiation risks. Therefore, there is an urgent need to develop a system and method capable of efficiently, safely, and accurately detecting the distribution of toxic gas gradients in confined spaces. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a confined space toxic gas gradient detection system and method based on a retractable probe. This system is simple in structure, low in manufacturing cost, highly automated, and has a high safety factor. It is also easy to carry and use. It can automatically perform high-precision gradient detection of toxic gases in the vertical direction within a confined space, eliminating the need for personnel to personally enter high-risk areas. This solves the technical problem of traditional single-point detection failing to identify deep hazardous areas and significantly improves the efficiency and safety of toxic gas detection in confined spaces. The method is simple to implement and highly automated, enabling high-precision gradient detection of toxic gases in the vertical direction within a confined space and obtaining a complete gas concentration gradient distribution model in the vertical direction.

[0005] To achieve the above objectives, the present invention provides a confined space toxic gas gradient detection system based on a telescopic probe, comprising an electric telescopic probe, a cross bracket, an integrated sensor module, and a controller;

[0006] The electric telescopic pole includes a telescopic assembly and an electric drive mechanism. The telescopic assembly includes a main pole body, a primary telescopic pole disposed within the main pole body, and a secondary telescopic pole disposed within the primary telescopic pole. The electric drive mechanism is installed inside the main pole body and is connected to the primary and secondary telescopic poles through an internal linkage mechanism. It is used to drive the secondary and primary telescopic poles to extend and retract axially section by section.

[0007] The cross bracket is horizontally arranged, with a mounting hole in its center, and is fixedly fitted onto the outer side of the end of the secondary telescopic rod through the mounting hole;

[0008] The number of integrated sensor modules is 9. Among them, 4 integrated sensor modules are fixedly installed below the four ends of the cross bracket, 1 integrated sensor module is fixedly installed below the center of the cross bracket, and 4 integrated sensor modules are fixedly installed below the middle section of the 4 support arms. The integrated sensor modules include a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, and an ultrasonic sensor.

[0009] The controller is connected to both the electric drive mechanism and the integrated sensor module.

[0010] Furthermore, in order to facilitate obtaining the spatial coordinate information of each detection plane, the integrated sensor module also includes a positioning module.

[0011] Furthermore, to ensure control precision during the telescopic process and to effectively ensure the service life of the electric telescopic pole, the electric drive mechanism is a stepper motor; the electric telescopic pole is made of carbon fiber composite material with a corrosion resistance rating of IP68; the telescopic accuracy of the electric telescopic pole is 0.1m, and its telescopic accuracy error is ≤±0.05m.

[0012] Furthermore, in order to facilitate interactive communication with external devices and to enable timely warning actions when dangerous situations are detected, a communication module and an alarm are also included. Both the communication module and the alarm are installed on the electric telescopic pole and are connected to the controller.

[0013] Furthermore, in order to facilitate interactive communication with the controller and to analyze and process the detection data sent by the controller, a data processing terminal is also included. The data processing terminal is installed in the control center and is connected to the controller via wireless or wired communication.

[0014] Furthermore, to ensure the detection accuracy of toxic gases, the hydrogen sulfide electrochemical sensor has a range of 0-100ppm and a response time of ≤5s, the oxygen optical sensor has a measurement accuracy of ±0.5%VOL, and to ensure the detection range, the laser ranging module has a measurement range of 0.1-20m.

[0015] As a preferred embodiment, the controller is a PLC controller.

[0016] In this invention, a telescopic assembly with multi-stage telescopic rods serves as the supporting body for the integrated sensor module. An electric drive mechanism drives the extension and retraction of the telescopic assembly, precisely controlling the depth of the integrated sensor module. This allows for detection operations at different depths in the vertical direction, significantly improving continuous detection capabilities in the vertical space. By installing a cross-shaped bracket at the lower end of the electric telescopic rod, and then spaced multiple integrated sensor modules at the lower end of the cross-shaped bracket, the detection area can be effectively expanded using the cross-shaped bracket. By integrating a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, and an ultrasonic sensor into the integrated sensor module, the concentrations of hydrogen sulfide and oxygen at different depths of the detection plane can be simultaneously detected. This allows for comprehensive perception of hydrogen sulfide and oxygen concentration data at various depths of the detection planes throughout the entire detection range. This facilitates the construction of a complete gas concentration gradient distribution model in the vertical direction using the detection data from each detection plane, greatly improving safety during operations in confined spaces. On the other hand, the initial detection depth can be detected by the laser ranging module, which is helpful to determine the extension step distance based on the detection depth. At the same time, obstacle data around each detection plane can be obtained by the ultrasonic sensor, which is helpful to form obstacle coordinate constraints around the detection position based on the obstacle data. Furthermore, after the three-dimensional gas concentration distribution model is constructed, the obstacle coordinate constraints can be combined to generate an accurate vertical gradient distribution map, which can more effectively guide the detection actions of subsequent personnel entering the detection operation environment and help ensure the personal safety of the operators.

[0017] The system is simple in structure, low in manufacturing cost, highly automated, and has a high safety factor. It is also easy to carry and use. It can automatically perform high-precision gradient detection of toxic gases in the vertical direction in confined spaces without requiring operators to personally enter high-risk areas to perform detection work. It solves the technical problem that traditional single-point detection cannot identify deep dangerous areas, significantly improves the efficiency and safety of toxic gas detection in confined spaces, and provides reliable safety protection for operators.

[0018] This invention also provides a method for detecting toxic gas gradients in a confined space based on a retractable probe, employing a system for detecting toxic gas gradients in a confined space based on a retractable probe, comprising the following steps:

[0019] Step 1: Select the detection position in the limited space to be detected, and fix the electric telescopic rod vertically at the top of the detection position. At the same time, ensure that the telescopic component is in the fully retracted state in the initial state.

[0020] Step 2: The laser ranging module in each integrated sensor module collects the depth signal from the cross brace to the bottom of the confined space in the initial state and sends it to the controller. The controller obtains the corresponding depth data based on the depth signal emitted by each integrated sensor module, and determines whether there are obstacles within the coverage area of ​​the cross brace based on the obtained depth data. If there are obstacles, Step 1 is executed again to reselect the detection position. If there are no obstacles, the vertical detection range is initially divided into multiple detection planes according to the current initial state depth data, and the detection time required for each detection plane is determined.

[0021] Step 3: The controller controls the telescopic components to extend in stages according to the extension step and detection time, so as to carry out the detection operation of different detection planes from top to bottom.

[0022] After each stage of the elongation action is completed, the spatial coordinate information of the current detection point on the current detection plane is collected by the positioning module in each integrated sensor module and sent to the controller. The ultrasonic sensor in each integrated sensor module collects the obstacle signal around the current detection point on the current detection plane and sends it to the controller. The hydrogen sulfide electrochemical sensor in each integrated sensor module collects the hydrogen sulfide gas concentration signal at the current detection point on the current detection plane in real time and sends it to the controller. The oxygen optical sensor in each integrated sensor module collects the oxygen concentration signal at the current detection point on the current detection plane in real time and sends it to the controller.

[0023] The controller obtains obstacle data around the current detection point on the current detection plane based on obstacle signals, hydrogen sulfide gas concentration data on the current detection plane based on hydrogen sulfide gas concentration signals at the current detection point, and oxygen concentration data on the current detection plane based on oxygen concentration signals at the current detection point, and records and stores the data.

[0024] After completing the detection work on two detection planes, compare the hydrogen sulfide gas concentration data and oxygen concentration data of the vertical corresponding detection points on the two adjacent detection planes. When the change rate of hydrogen sulfide gas concentration data is >3ppm / 0.5m or the difference in oxygen concentration gradient is >5%VOL / 0.5m, modify the extension step distance in the subsequent stage to half of the previous extension step distance; otherwise, do not modify the extension step distance.

[0025] After completing the detection operation across the entire vertical detection range, the controller transmits the spatial coordinates of each detection point on each detection plane, obstacle data around each detection point on each detection plane, hydrogen sulfide gas concentration data at each detection point on each detection plane, and oxygen concentration data at each detection point on each detection plane to the data processing terminal located in the control center via the communication module.

[0026] Step 4: The data processing terminal summarizes the obstacle data and spatial coordinate information of each detection point on each detection plane, and uses the built-in 3D reconstruction module to generate obstacle coordinate constraints around the detection location. Simultaneously, the data processing terminal summarizes the hydrogen sulfide and oxygen concentration data of each detection point on each detection plane, obtaining the toxic gas concentration distribution data at each detection point in the vertical direction of different detection planes. Based on this toxic gas concentration distribution data, the built-in 3D concentration distribution prediction module uses an interpolation algorithm to construct a 3D concentration distribution prediction system with a resolution of less than or equal to 0.1m in the vertical direction of a limited space. A three-dimensional gas concentration distribution model is constructed, and an accurate vertical gradient distribution map is generated within the model, incorporating obstacle coordinate constraints. Simultaneously, using 19.5% oxygen concentration and 7 ppm hydrogen sulfide concentration as critical values, red and green regions are marked vertically. When the oxygen concentration in any region is below 19.5% or the hydrogen sulfide concentration is above 7 ppm, it is designated as a red restricted area and displayed as such in the three-dimensional gas concentration distribution model, with its coordinates marked. Conversely, when the oxygen concentration in any region is equal to or higher than 19.5% or the hydrogen sulfide concentration is equal to or lower than 7 ppm, it is designated as a green safe zone and displayed as such in the three-dimensional gas concentration distribution model.

[0027] In order to achieve vertical gradient detection of toxic gas concentration and accurate delineation of hazardous areas, in step four, the interpolation algorithm is the Kriging interpolation algorithm. In the process of constructing a three-dimensional gas concentration distribution model using the interpolation algorithm, the predicted concentration value C(Z0) at any position Z0 in the adjacent detection layer is calculated according to formula (1). pre ;

[0028]

[0029] In the formula, d(Z) i Z0) is a known point Z i The perpendicular distance between the point and the point to be interpolated Z0, where Z is the perpendicular distance between the point and the point to be interpolated. i The detection plane above the location of Z0; Given point Z iThe absolute value of the concentration gradient at a given point; α is the gradient sensitivity coefficient, dynamically adjusted based on the hydrogen sulfide / oxygen concentration threshold. Traditional Kriging methods rely on semivariograms to calculate weights; this invention innovatively adjusts the gradient sensitivity weights through a decay term. This invention directly incorporates the influence of concentration gradients, simplifying the calculation process and reducing computational load, thus improving computational efficiency. In high gradient regions (such as near toxic gas leak points), the gradient term automatically reduces the weight of distant points, prioritizing neighboring data, meeting the requirements of adaptive sampling and facilitating more accurate calculation results. Furthermore, based on the need for continuous detection in the vertical direction, this invention innovatively focuses on the vertical direction, requiring only the calculation of the vertical distance d(Z). i The method (Z0) ignores horizontal differences, adapts to vertical layer interpolation scenarios, and further reduces the computational process and workload, thus improving computational efficiency. Furthermore, this invention innovatively employs dynamic coefficient adaptation: coefficient α can be adjusted according to the gradient threshold of hydrogen sulfide (3ppm / 0.5m) or oxygen (5% VOL / 0.5m), achieving parameterized adaptation and facilitating the construction of a more accurate complete gas concentration gradient distribution model.

[0030] As a preferred embodiment, in step three, when the oxygen concentration is below 19.5% or the hydrogen sulfide concentration is above 7 ppm, the controller activates the alarm to trigger an audible and visual alarm, effectively alerting relevant personnel.

[0031] This invention overcomes the shortcomings of existing technologies and provides a method for detecting toxic gas gradients in confined spaces based on a retractable probe. This method significantly improves continuous vertical detection capabilities by electrically controlling segmented retractable components. Furthermore, it eliminates the need for personnel to manually enter high-risk areas for detection, resulting in a high safety factor. By integrating a positioning module, a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, and an ultrasonic sensor into the integrated sensor module, multiple detection functions are achieved. This allows for convenient acquisition of spatial coordinates of different depth detection planes, hydrogen sulfide gas concentration, oxygen gas concentration, depth data from the bottom, and obstacle data. This facilitates the construction of a three-dimensional gas concentration distribution model with a resolution of ≤0.1m using interpolation algorithms, and the generation of accurate vertical gradient distribution maps can be achieved by combining obstacle coordinate constraints. The interpolation algorithm can derive continuous distribution data from discrete detection point data across multiple detection planes. Simultaneously, when the rate of change of hydrogen sulfide gas concentration data on adjacent detection planes exceeds 3 ppm / 0.5 m or the oxygen concentration gradient difference exceeds 5% VOL / 0.5 m, the subsequent extension step distance is automatically adjusted to half of the previous extension step distance. This dynamic adjustment of the extension step distance significantly improves the detection density of abnormal areas, accurately capturing the accumulation of hydrogen sulfide at the bottom and accurately assessing the risk of deep high-concentration areas. This solves the problem of missed detections in deep areas caused by traditional single-point detection and further improves the accuracy of the three-dimensional gas concentration distribution model. The introduction of obstacle coordinate constraints ensures that the generated three-dimensional gas concentration distribution model is consistent with the actual situation within the confined space, facilitating safer and more effective guidance for subsequent operations. Based on this, using oxygen concentration of 19.5% and hydrogen sulfide concentration of 7ppm as critical values, a vertical distribution map of red restricted areas and green safe areas is automatically generated. By marking areas of sudden concentration changes, the limitations of traditional modeling are effectively overcome, providing real-time visual decision support for operators. This can effectively guide the actions of subsequent personnel entering the detection operation, help ensure the safety of operators, and significantly reduce the risk of accidents in subsequent operations.

[0032] This method is simple to implement and highly automated. It innovatively achieves high-precision gradient detection of toxic gases in the vertical direction within a confined space, and can obtain a complete gas concentration gradient distribution model in the vertical direction. It solves the technical problem that traditional single-point detection cannot accurately identify gas accumulation in deep dangerous areas, and significantly improves the efficiency, accuracy and safety of toxic gas detection in confined spaces, providing reliable safety protection for operators. Attached Figure Description

[0033] Figure 1This is a schematic diagram illustrating the use of an electric telescopic rod to detect the concentration of toxic gases in a confined space in this invention.

[0034] Figure 2 This is a schematic diagram of the control section in this invention;

[0035] Figure 3 This is a schematic diagram of the fully retracted state of the electric telescopic rod in this invention;

[0036] Figure 4 This is a schematic diagram of the electric telescopic rod in its fully extended state according to the present invention;

[0037] Figure 5 This is a schematic diagram of the integrated sensor module in this invention;

[0038] Figure 6 A schematic diagram illustrating the method for determining the critical values ​​of hydrogen sulfide and oxygen concentrations when defining the red and green regions in the vertical direction of a finite space.

[0039] In the diagram: 1. Electric telescopic pole; 1-1. Main pole body; 1-2. First-stage telescopic pole; 1-3. Second-stage telescopic pole; 2. Integrated sensor module; 2-1. Hydrogen sulfide electrochemical sensor; 2-2. Oxygen optical sensor; 2-3. Laser ranging module; 2-4. Ultrasonic sensor; 2-5. Positioning module; 3. Limited space; 4. Cross bracket. Detailed Implementation

[0040] The invention will now be further described with reference to the accompanying drawings.

[0041] like Figures 1 to 5 As shown, the present invention provides a toxic gas gradient detection system in a confined space based on a telescopic probe, including an electric telescopic probe 1, a cross bracket 4, an integrated sensor module 2, and a controller;

[0042] The electric telescopic pole 1 includes a telescopic assembly and an electric drive mechanism. The telescopic assembly includes a main pole body 1-1, a primary telescopic pole 1-2 disposed within the main pole body 1, and a secondary telescopic pole 1-3 disposed within the primary telescopic pole 1-2. The electric drive mechanism is installed inside the main pole body 1-1 and is connected to the primary telescopic pole 1-2 and the secondary telescopic pole 1-3 through an internal linkage mechanism. It is used to drive the secondary telescopic pole 1-3 and the primary telescopic pole 1-2 to extend and retract axially section by section. The primary telescopic pole 1-2 can only move axially relative to the main pole body 1 and will not rotate radially, and the secondary telescopic pole 1-3 can only move axially relative to the primary telescopic pole 1-2 and will not rotate radially.

[0043] The cross bracket 4 is horizontally arranged, with a mounting hole in its center, and is fixedly fitted onto the outer side of the ends of the secondary telescopic rod 1-3 through the mounting hole;

[0044] The number of integrated sensor modules 2 is 9, of which 4 integrated sensor modules 2 are fixedly installed below the four ends of the cross bracket 4, 1 integrated sensor module 2 is fixedly installed below the center of the cross bracket 4, and 4 integrated sensor modules 2 are fixedly installed below the middle section of the 4 support arms; the integrated sensor modules 2 include hydrogen sulfide electrochemical sensor 2-1, oxygen optical sensor 2-2, laser ranging module 2-3 and ultrasonic sensor 2-4;

[0045] The controller is connected to the electric drive mechanism and the integrated sensor module 2, respectively.

[0046] To facilitate obtaining spatial coordinate information of each detection plane, the integrated sensor module 2 also includes positioning modules 2-5.

[0047] To ensure control precision during the telescopic process and to effectively ensure the service life of the electric telescopic pole, the electric drive mechanism is a stepper motor; the electric telescopic pole 1 is made of carbon fiber composite material with a corrosion resistance rating of IP68; the telescopic accuracy of the electric telescopic pole 1 is 0.1m, and its telescopic accuracy error is ≤±0.05m. The electric telescopic pole in this invention can be an existing electric telescopic pole.

[0048] To facilitate communication with external devices and to enable timely warning actions in case of danger, a communication module and an alarm are included. Both the communication module and the alarm are mounted on the electric telescopic pole 1 and connected to the controller. Preferably, a power supply module is also included for supplying electricity.

[0049] To facilitate interactive communication with the controller and to analyze and process the detection data sent by the controller, a data processing terminal is also included. The data processing terminal is installed in the control center and is connected to the controller via wireless or wired communication.

[0050] To ensure the detection accuracy of toxic gases, the hydrogen sulfide electrochemical sensor 2-1 has a range of 0-100ppm and a response time of ≤5s. The oxygen optical sensor 2-2 has a measurement accuracy of ±0.5%VOL. To ensure the detection range, the laser ranging module 2-3 has a measurement range of 0.1-20m.

[0051] As a preferred embodiment, the controller is a PLC controller.

[0052] In this invention, a telescopic assembly with multi-stage telescopic rods serves as the supporting body for the integrated sensor module. An electric drive mechanism drives the extension and retraction of the telescopic assembly, precisely controlling the depth of the integrated sensor module. This allows for detection operations at different depths in the vertical direction, significantly improving continuous detection capabilities in the vertical space. By installing a cross-shaped bracket at the lower end of the electric telescopic rod, and then spaced multiple integrated sensor modules at the lower end of the cross-shaped bracket, the detection area can be effectively expanded using the cross-shaped bracket. By integrating a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, and an ultrasonic sensor into the integrated sensor module, the concentrations of hydrogen sulfide and oxygen at different depths of the detection plane can be simultaneously detected. This allows for comprehensive perception of hydrogen sulfide and oxygen concentration data at various depths of the detection planes throughout the entire detection range. This facilitates the construction of a complete gas concentration gradient distribution model in the vertical direction using the detection data from each detection plane, greatly improving safety during operations in confined spaces. On the other hand, the initial detection depth can be detected by the laser ranging module, which is helpful to determine the extension step distance based on the detection depth. At the same time, obstacle data around each detection plane can be obtained by the ultrasonic sensor, which is helpful to form obstacle coordinate constraints around the detection position based on the obstacle data. Furthermore, after the three-dimensional gas concentration distribution model is constructed, the obstacle coordinate constraints can be combined to generate an accurate vertical gradient distribution map, which can more effectively guide the detection actions of subsequent personnel entering the detection operation environment and help ensure the personal safety of the operators.

[0053] The system is simple in structure, low in manufacturing cost, highly automated, and has a high safety factor. It is also easy to carry and use. It can automatically perform high-precision gradient detection of toxic gases in the vertical direction in confined spaces without requiring operators to personally enter high-risk areas to perform detection work. It solves the technical problem that traditional single-point detection cannot identify deep dangerous areas, significantly improves the efficiency and safety of toxic gas detection in confined spaces, and provides reliable safety protection for operators.

[0054] This invention also provides a method for detecting toxic gas gradients in a confined space based on a retractable probe, employing a system for detecting toxic gas gradients in a confined space based on a retractable probe, comprising the following steps:

[0055] Step 1: Select the detection position in the limited space 3 to be detected, and fix the electric telescopic rod 1 vertically at the top of the detection position. At the same time, ensure that the telescopic component is in the fully retracted state in the initial state.

[0056] Step 2: The laser ranging module 2-3 in each integrated sensor module 2 collects the depth signal from the cross bracket 4 to the bottom of the confined space 3 in the initial state and sends it to the controller. The controller obtains the corresponding depth data based on the depth signal emitted by each integrated sensor module 2, and determines whether there are obstacles within the coverage area of ​​the cross bracket 4 based on the obtained depth data. If there are obstacles, Step 1 is executed again to reselect the detection position. If there are no obstacles, the vertical detection range is initially divided into multiple detection planes according to the current initial state depth data in the form of equal extension step distance. For example, from top to bottom, they can be horizontal detection plane A, horizontal detection plane B, horizontal detection plane C, horizontal detection plane D, horizontal detection plane E, horizontal detection plane F and horizontal detection plane G. At the same time, the detection time required for each detection plane is determined.

[0057] Step 3: The controller controls the telescopic components to extend in stages according to the extension step and detection time, so as to perform detection operations on different detection planes (A horizontal detection plane, B horizontal detection plane, C horizontal detection plane, D horizontal detection plane, E horizontal detection plane, F horizontal detection plane and G horizontal detection plane) from top to bottom.

[0058] After each stage of elongation, the spatial coordinate information of the current detection point on the current detection plane is collected by the positioning module 2-5 in each integrated sensor module 2 and sent to the controller. The ultrasonic sensor 2-4 in each integrated sensor module 2 is collected by the obstacle signal around the current detection point on the current detection plane and sent to the controller. The hydrogen sulfide electrochemical sensor 2-1 in each integrated sensor module 2 is collected in real time by the hydrogen sulfide gas concentration signal at the current detection point on the current detection plane and sent to the controller. The oxygen optical sensor 2-2 in each integrated sensor module 2 is collected in real time by the oxygen concentration signal at the current detection point on the current detection plane and sent to the controller.

[0059] The controller obtains obstacle data around the current detection point on the current detection plane based on obstacle signals, hydrogen sulfide gas concentration data on the current detection plane based on hydrogen sulfide gas concentration signals at the current detection point, and oxygen concentration data on the current detection plane based on oxygen concentration signals at the current detection point, and records and stores the data.

[0060] After completing the detection work on two detection planes, the hydrogen sulfide gas concentration data and oxygen concentration data of the vertical corresponding detection points of the two adjacent detection planes are compared. When the change rate of hydrogen sulfide gas concentration data is >3ppm / 0.5m or the difference in oxygen concentration gradient is >5%VOL / 0.5m, the extension step size in the subsequent stage is modified to half of the previous extension step size. This can effectively increase the sampling density of the abnormal area and help ensure a more accurate three-dimensional gas concentration distribution model. Otherwise, the extension step size is not modified.

[0061] After completing the detection operation of the entire vertical detection range, the controller sends the spatial coordinate information of each detection point on each detection plane, the obstacle data around each detection point on each detection plane, the hydrogen sulfide gas concentration data of each detection point on each detection plane, and the oxygen concentration data of each detection point on each detection plane to the data processing terminal located in the control center through the communication module.

[0062] Step 4: The data processing terminal summarizes the obstacle data and spatial coordinate information of each detection point on each detection plane, and uses the built-in 3D reconstruction module to generate obstacle coordinate constraints around the detection location. Simultaneously, the data processing terminal summarizes the hydrogen sulfide and oxygen concentration data of each detection point on each detection plane, obtaining the toxic gas concentration distribution data at each detection point in the vertical direction of different detection planes. Based on this toxic gas concentration distribution data, the built-in 3D concentration distribution prediction module uses an interpolation algorithm to construct a 3D gas concentration distribution model with a resolution of less than or equal to 0.1m (preferably 0.05m) in the vertical direction of a finite space. In conjunction with obstacle coordinate constraints, an accurate vertical gradient distribution map is generated in the 3D gas concentration distribution model. Simultaneously, using 19.5% oxygen concentration and 7ppm hydrogen sulfide concentration as critical values, red and green areas are marked vertically. When the oxygen concentration in any area is below 19.5% or the hydrogen sulfide concentration is above 7ppm, it is designated as a red restricted area (high-concentration hydrogen sulfide restricted area, low-oxygen restricted area), and displayed as a red area in the 3D gas concentration distribution model, with its coordinates marked. When the oxygen concentration in any area is above or equal to 19.5% or the hydrogen sulfide concentration is below or equal to 7ppm, it is designated as a green safe area (safe working area), and displayed as a green area in the 3D gas concentration distribution model. The specific division method is as follows: Figure 6 As shown.

[0063] In order to achieve vertical gradient detection of toxic gas concentration and accurate delineation of hazardous areas, in step four, the interpolation algorithm is the Kriging interpolation algorithm. In the process of constructing a three-dimensional gas concentration distribution model using the interpolation algorithm, the predicted concentration value C(Z0) at any position Z0 in the adjacent detection layer is calculated according to formula (1). pre ;

[0064]

[0065] In the formula, d(Z) i Z0) is a known point Z i The perpendicular distance between the point and the point to be interpolated Z0, where Z is the perpendicular distance between the point and the point to be interpolated. i The detection plane above the location of Z0; Given point Z i The absolute value of the concentration gradient at a given point; α is the gradient sensitivity coefficient, dynamically adjusted according to the hydrogen sulfide / oxygen concentration thresholds. Preferably, the gradient sensitivity coefficient for hydrogen sulfide is 0.5, and the gradient sensitivity coefficient for oxygen is 0.3. Traditional Kriging methods rely on semi-variograms to calculate weights. This invention innovatively adjusts the gradient sensitivity weights through a decay term. This invention directly incorporates the influence of concentration gradients, simplifying the calculation process and reducing computational load, thus improving computational efficiency. In high gradient regions (such as near toxic gas leak points), the gradient term automatically reduces the weight of distant points, prioritizing neighboring data, meeting the requirements of adaptive sampling and facilitating more accurate calculation results. Furthermore, based on the need for continuous detection in the vertical direction, this invention innovatively focuses on the vertical direction, requiring only the calculation of the vertical distance d(Z). i The method (Z0) ignores horizontal differences, adapts to vertical layer interpolation scenarios, and further reduces the computational process and workload, thus improving computational efficiency. Furthermore, this invention innovatively employs dynamic coefficient adaptation: coefficient α can be adjusted according to the gradient threshold of hydrogen sulfide (3ppm / 0.5m) or oxygen (5% VOL / 0.5m), achieving parameterized adaptation and facilitating the construction of a more accurate complete gas concentration gradient distribution model.

[0066] As a preferred embodiment, in step three, when the oxygen concentration is below 19.5% or the hydrogen sulfide concentration is above 7 ppm, the controller activates the alarm to trigger an audible and visual alarm, effectively alerting relevant personnel.

[0067] This invention overcomes the shortcomings of existing technologies and provides a method for detecting toxic gas gradients in confined spaces based on a retractable probe. This method significantly improves continuous vertical detection capabilities by electrically controlling segmented retractable components. Furthermore, it eliminates the need for personnel to manually enter high-risk areas for detection, resulting in a high safety factor. By integrating a positioning module, a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, and an ultrasonic sensor into the integrated sensor module, multiple detection functions are achieved. This allows for convenient acquisition of spatial coordinates of different depth detection planes, hydrogen sulfide gas concentration, oxygen gas concentration, depth data from the bottom, and obstacle data. This facilitates the construction of a three-dimensional gas concentration distribution model with a resolution of ≤0.1m using interpolation algorithms, and the generation of accurate vertical gradient distribution maps can be achieved by combining obstacle coordinate constraints. The interpolation algorithm can derive continuous distribution data from discrete detection point data across multiple detection planes. Simultaneously, when the rate of change of hydrogen sulfide gas concentration data on adjacent detection planes exceeds 3 ppm / 0.5 m or the oxygen concentration gradient difference exceeds 5% VOL / 0.5 m, the subsequent extension step distance is automatically adjusted to half of the previous extension step distance. This dynamic adjustment of the extension step distance significantly improves the detection density of abnormal areas, accurately capturing the accumulation of hydrogen sulfide at the bottom and accurately assessing the risk of deep high-concentration areas. This solves the problem of missed detections in deep areas caused by traditional single-point detection and further improves the accuracy of the three-dimensional gas concentration distribution model. The introduction of obstacle coordinate constraints ensures that the generated three-dimensional gas concentration distribution model is consistent with the actual situation within the confined space, facilitating safer and more effective guidance for subsequent operations. Based on this, using oxygen concentration of 19.5% and hydrogen sulfide concentration of 7ppm as critical values, a vertical distribution map of red restricted areas and green safe areas is automatically generated. By marking areas of sudden concentration changes, the limitations of traditional modeling are effectively overcome, providing real-time visual decision support for operators. This can effectively guide the actions of subsequent personnel entering the detection operation, help ensure the safety of operators, and significantly reduce the risk of accidents in subsequent operations.

[0068] This method is simple to implement and highly automated. It innovatively achieves high-precision gradient detection of toxic gases in the vertical direction within a confined space, and can obtain a complete gas concentration gradient distribution model in the vertical direction. It solves the technical problem that traditional single-point detection cannot accurately identify gas accumulation in deep dangerous areas, and significantly improves the efficiency, accuracy and safety of toxic gas detection in confined spaces, providing reliable safety protection for operators.

Claims

1. A method for detecting toxic gas gradients in a confined space based on a telescopic probe, comprising a system for detecting toxic gas gradients in a confined space based on a telescopic probe, the system including an electric telescopic probe, a cross bracket, an integrated sensor module, and a controller. The electric telescopic probe includes a telescopic assembly and an electric drive mechanism. The telescopic assembly includes a main body, a primary telescopic probe housed within the main body, and a secondary telescopic probe housed within the primary telescopic probe. The electric drive mechanism is installed inside the main body and connected to the primary and secondary telescopic probes via an internal linkage mechanism. The cross bracket is horizontally positioned with a central mounting hole, and is fixedly fitted onto the outer side of the end of the secondary telescopic probe through the mounting hole. The integrated sensor module includes a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, an ultrasonic sensor, and a positioning module. The number of integrated sensor modules is nine. Four integrated sensor modules are fixedly installed below the four ends of the cross bracket, one integrated sensor module is fixedly installed below the center of the cross bracket, and four integrated sensor modules are fixedly installed below the middle sections of the four support arms; the controller is connected to the electric drive mechanism and the integrated sensor modules respectively. Its characteristic is that it includes the following steps: Step 1: Select the detection position in the limited space to be detected, and fix the electric telescopic rod vertically at the top of the detection position. At the same time, ensure that the telescopic component is in the fully retracted state in the initial state. Step 2: The laser ranging module in each integrated sensor module collects the depth signal from the cross brace to the bottom of the confined space in the initial state and sends it to the controller. The controller obtains the corresponding depth data based on the depth signal emitted by each integrated sensor module, and determines whether there are obstacles within the coverage area of ​​the cross brace based on the obtained depth data. If there are obstacles, Step 1 is executed again to reselect the detection position. If there are no obstacles, the vertical detection range is initially divided into multiple detection planes according to the current initial state depth data, and the detection time required for each detection plane is determined. Step 3: The controller controls the telescopic components to extend in stages according to the extension step and detection time, so as to carry out the detection operation of different detection planes from top to bottom. After each stage of the elongation action is completed, the spatial coordinate information of the current detection point on the current detection plane is collected by the positioning module in each integrated sensor module and sent to the controller. The ultrasonic sensor in each integrated sensor module collects the obstacle signal around the current detection point on the current detection plane and sends it to the controller. The hydrogen sulfide electrochemical sensor in each integrated sensor module collects the hydrogen sulfide gas concentration signal at the current detection point on the current detection plane in real time and sends it to the controller. The oxygen optical sensor in each integrated sensor module collects the oxygen concentration signal at the current detection point on the current detection plane in real time and sends it to the controller. The controller obtains obstacle data around the current detection point on the current detection plane based on obstacle signals, hydrogen sulfide gas concentration data at the current detection point on the current detection plane based on hydrogen sulfide gas concentration signals, and oxygen concentration data at the current detection point on the current detection plane based on oxygen concentration signals, and records and stores the data. After completing the detection work on two detection planes, compare the hydrogen sulfide gas concentration data and oxygen concentration data at the vertical corresponding detection points of the two adjacent detection planes. When the change rate of hydrogen sulfide gas concentration data is >3ppm / 0.5m or the difference in oxygen concentration gradient is >5%VOL / 0.5m, modify the extension step distance in the subsequent stage to half of the previous extension step distance; otherwise, do not modify the extension step distance. After completing the detection operation of the entire vertical detection range, the controller sends the spatial coordinate information of each detection point on each detection plane, the obstacle data around each detection point on each detection plane, the hydrogen sulfide gas concentration data of each detection point on each detection plane, and the oxygen concentration data of each detection point on each detection plane to the data processing terminal located in the control center through the communication module. Step 4: The data processing terminal summarizes the obstacle data and spatial coordinate information of each detection point on each detection plane, and uses the built-in three-dimensional reconstruction module to generate obstacle coordinate constraints around the detection position. At the same time, the data processing terminal summarizes the hydrogen sulfide gas concentration data and oxygen concentration data of each detection point on each detection plane, and obtains the toxic gas concentration distribution data of each detection point on different detection planes in the vertical direction. Based on the toxic gas concentration distribution data of each detection point on different detection planes, the built-in three-dimensional concentration distribution prediction module uses the Kriging interpolation algorithm to construct a three-dimensional gas concentration distribution model with a resolution of less than or equal to 0.1m in the vertical direction of a limited space. In the process of constructing the three-dimensional gas concentration distribution model, the predicted concentration value at any position Z0 in the adjacent detection plane is calculated according to formula (1). The system generates an accurate vertical gradient distribution map in the three-dimensional gas concentration distribution model by combining obstacle coordinate constraints. Simultaneously, using 19.5% oxygen concentration and 7ppm hydrogen sulfide concentration as critical values, red and green areas are marked in the vertical direction. When the oxygen concentration in any area is below 19.5% or the hydrogen sulfide concentration is above 7ppm, it is designated as a red restricted area and displayed as such in the three-dimensional gas concentration distribution model. The coordinates of the red areas are also marked. When the oxygen concentration in any area is above or equal to 19.5% or the hydrogen sulfide concentration is below or equal to 7ppm, it is designated as a green safe area and displayed as such in the three-dimensional gas concentration distribution model. （1）； In the formula, For known points Location and interpolation point The vertical distance at point, where, for The detection plane above the location; Given point Z i The absolute value of the concentration gradient at that location; This is a gradient sensitivity coefficient, dynamically adjusted based on hydrogen sulfide / oxygen concentration thresholds.

2. The method for detecting toxic gas gradients in a confined space based on a retractable probe according to claim 1, characterized in that, In step three, when the oxygen concentration is below 19.5% or the hydrogen sulfide concentration is above 7 ppm, the controller activates the alarm to trigger an audible and visual alarm, effectively alerting relevant personnel.

3. The method for detecting toxic gas gradients in a confined space based on a retractable probe according to claim 1, characterized in that, The electric drive mechanism is a stepper motor; the electric telescopic rod is made of carbon fiber composite material with a corrosion resistance rating of IP68; the telescopic accuracy of the electric telescopic rod is 0.1m, and its telescopic accuracy error is ≤±0.05m.

4. The method for detecting toxic gas gradients in a confined space based on a retractable probe according to claim 1, characterized in that, It also includes a communication module and an alarm, both of which are mounted on the electric telescopic pole and connected to the controller.

5. The method for detecting toxic gas gradients in a confined space based on a retractable probe according to claim 1, characterized in that, It also includes a data processing terminal, which is installed in the control center and connected to the controller via wireless or wired communication.

6. The method for detecting toxic gas gradients in a confined space based on a retractable probe according to claim 1, characterized in that, The hydrogen sulfide electrochemical sensor has a measurement range of 0-100ppm and a response time of ≤5s. The oxygen optical sensor has a measurement accuracy of ±0.5%VOL. The laser ranging module has a measurement range of 0.1-20m.

7. The method for detecting toxic gas gradients in a confined space based on a retractable probe according to claim 1, characterized in that, The controller is a PLC controller.

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