Limited space toxic gas gradient detection system and method based on telescopic probe rod

Abstract

According to the limited space toxic gas gradient detection system and method based on the telescopic probe rod, an electric telescopic rod comprises a telescopic assembly, a cross-shaped support and an electric driving mechanism, and the telescopic assembly comprises a main rod body, a first-stage telescopic rod and a second-stage telescopic rod; the electric driving mechanism is installed in the main rod body and used for driving the second-stage telescopic rod and the first-stage telescopic rod to stretch and retract in the axial direction section by section. The cross-shaped bracket is mounted at the end part of the secondary telescopic rod; the plurality of integrated sensor modules are mounted at the lower end of the cross-shaped bracket at intervals; the method comprises the steps that detection operation is conducted on different detection planes in a staged mode according to the elongation step pitch, obtained detection data are sent to the data processing terminal, and the data processing terminal generates a three-dimensional gas concentration distribution model based on the detection data and generates an accurate vertical gradient distribution diagram in combination with obstacle coordinate constraint conditions. According to the system and the method, high-precision gradient detection operation of toxic gas in the vertical direction in a limited space can be automatically realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent detection of toxic gases, and specifically relates to a gradient detection system and method for toxic gases in confined spaces based on a telescopic probe rod. Background Art

[0002] In industries such as industrial and trade, chemical engineering, and municipal engineering, there are often confined spaces with complex working environments and poor ventilation. Toxic and harmful gases are likely to accumulate in such confined spaces, especially hydrogen sulfide. Due to its relatively high density, hydrogen sulfide gas accumulates at the bottom of the confined space and forms a concentration gradient distribution from top to bottom. In recent years, hydrogen sulfide poisoning accidents have occurred frequently. The main reason is that before entering the confined space, practitioners only perform single-point sampling and detection at the entrance or shallow layer positions, ignoring the gradient change of hydrogen sulfide concentration, and thus unable to accurately assess the risks in the deep high-concentration areas. Most of the existing gas detection devices are handheld single-point measurement equipment, lacking the ability to continuously detect in the vertical direction of the space. Moreover, the efficiency of manual sampling in high-risk areas is low, and there are great safety risks. The existing technologies can neither construct a gas concentration gradient distribution model nor delimit a safe operation restricted area based on real-time data, severely restricting the safety guarantee ability of confined space operations.

[0003] Since the traditional detection of toxic gases in confined spaces mainly relies on handheld single-point sampling equipment and cannot synchronously obtain gas concentration gradient data in the vertical direction, it leads to misjudgment of high-risk areas by operators. In the existing technologies, although some technologies have specifically proposed improvement schemes, there are still obvious deficiencies. For example, the insertion-type detector proposed in the existing technology has a telescopic function but lacks multi-dimensional scanning ability and does not integrate a space modeling module; the probe protection mechanism proposed in the existing technology optimizes the equipment safety but does not solve the demand for high-precision gradient detection in the vertical direction; the ventilation detection collaborative system proposed in the existing technology has an automatic control function, but the fixed sensor layout is difficult to adapt to the characteristics of complex spaces. These defects in the existing technologies make it difficult for existing equipment to accurately identify the concentration gradient changes of toxic gases such as hydrogen sulfide and oxygen in the vertical direction in confined spaces, easily leading to misjudgment of poisoning and asphyxiation safety risks. Therefore, there is an urgent need to develop a system and method that can efficiently, safely, and accurately detect the gradient distribution of toxic gases in confined spaces. Summary of the Invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention provides a limited space toxic gas gradient detection system and method based on a telescopic probe rod. The system has a simple structure, low manufacturing cost, high automation degree, high safety factor, and is convenient to carry and use. It can automatically achieve high-precision gradient detection of toxic gases in the vertical direction in a limited space, without requiring operators to personally enter high-risk areas to perform detection operations. It can solve the technical problem that traditional single-point detection cannot identify deep dangerous areas, and can significantly improve the efficiency and safety of toxic gas detection in a limited space; the method has a simple implementation process and high automation degree, and can achieve high-precision gradient detection of toxic gases in the vertical direction in a limited space, and can obtain a complete gas concentration gradient distribution model in the vertical direction.

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

[0006] The electric telescopic rod includes a telescopic component and an electric drive mechanism. The telescopic component includes a main rod body, a first-stage telescopic rod arranged inside the main rod body, and a second-stage telescopic rod arranged inside the first-stage telescopic rod; the electric drive mechanism is installed inside the main rod body and is connected to the first-stage telescopic rod and the second-stage telescopic rod through an internal linkage mechanism for driving the second-stage telescopic rod and the first-stage telescopic rod to extend and retract axially one by one.

[0007] The cross bracket is horizontally arranged, and an installation hole is provided at its center and is fixedly sleeved outside the end of the second-stage telescopic rod through the installation hole;

[0008] The number of the integrated sensor modules is 9. Among them, 4 integrated sensor modules are respectively 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 respectively fixedly installed below the middle sections of the 4 arms; the integrated sensor module includes a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, and an ultrasonic sensor;

[0009] The controller is respectively connected to 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 further includes a positioning module.

[0011] Furthermore, in order to ensure the control accuracy during the telescopic process, and at the same time, in order to effectively ensure the service life of the electric telescopic rod, the electric drive mechanism is a stepping motor; the electric telescopic rod is made of carbon fiber composite material, and the corrosion resistance level is IP68; the telescopic accuracy of the electric telescopic rod is 0.1 m, and its telescopic accuracy error ≤ ±0.05 m.

[0012] Further, for facilitating the interactive communication with external devices and, at the same time, for facilitating the warning action in a timely manner when a dangerous situation is detected, a communication module and an alarm are further included. The communication module and the alarm are both installed on the electric telescopic rod and are both connected to the controller.

[0013] Further, for facilitating the interactive communication with the controller and, at the same time, for analyzing and processing the detection data sent by the controller, a data processing terminal is further included. The data processing terminal is installed in the control center and is connected to the controller by means of wireless communication or wired communication.

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

[0015] As a preference, the controller is a PLC controller.

[0016] In the present invention, a telescopic assembly with a multi-stage telescopic rod is used as the support body of the integrated sensor module. At the same time, an electric drive mechanism is used to drive the telescopic assembly to extend and retract, so that the downward probing depth of the integrated sensor module can be accurately controlled. Furthermore, detection operations at different depths can be realized in the vertical direction, and at the same time, the continuous detection ability in the vertical direction of the space is significantly improved. By installing a cross bracket at the lower end of the electric telescopic rod, and then installing a plurality of integrated sensor modules at intervals at the lower end of the cross bracket, it is convenient to effectively expand the coverage range of the detection area through the cross bracket. By integrating a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, and an ultrasonic sensor in the integrated sensor module, on the one hand, the hydrogen sulfide concentration and oxygen concentration at different depth detection planes can be synchronously detected. Thus, the hydrogen sulfide concentration and oxygen concentration data at each detection plane at different depths within the entire detection range can be comprehensively sensed. Furthermore, it is beneficial to use the detection data at each detection plane to construct a complete gas concentration gradient distribution model in the vertical direction, greatly improving the safety guarantee ability during the operation in a confined space. On the other hand, the initial probing depth can be detected through the laser ranging module, which is beneficial to preliminarily determine the elongation step distance according to the probing depth. At the same time, the obstacle data around each detection plane can be obtained through the ultrasonic sensor, which is beneficial to form the obstacle coordinate constraint conditions around the detection position according to the obstacle data around each detection plane. Further, after a three-dimensional gas concentration distribution model is constructed subsequently, an accurate vertical gradient distribution map can be generated in combination with the obstacle coordinate constraint conditions, so as to more effectively guide the subsequent probing actions of the personnel entering the detection operation environment, which is beneficial to ensuring the personal safety of the operating personnel.

[0017] The system has a simple structure, low manufacturing cost, high automation degree, high safety factor, and is convenient to carry and use. It can automatically achieve high-precision gradient detection of toxic gases in the vertical direction within a confined space, without the need for operating personnel to personally enter high-risk areas to perform detection operations, solving the technical problem that traditional single-point detection cannot identify deep dangerous areas, significantly improving the efficiency and safety of toxic gas detection in a confined space, and providing reliable safety guarantee for operating personnel.

[0018] The present invention also provides a method for detecting the gradient of toxic gases in a confined space based on a telescopic probe rod. Using a system for detecting the gradient of toxic gases in a confined space based on a telescopic probe rod, it includes the following steps:

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

[0020] Step 2: Use the laser ranging module in each integrated sensor module to collect the depth signal from the cross bracket to the bottom of the confined space in the initial state and send it to the controller; the controller obtains the corresponding depth data based on the depth signals sent by each integrated sensor module, and determines whether there are obstacles within the coverage of the cross bracket based on the obtained depth data. When there are obstacles, re-execute Step 1 to reselect the detection position. When there are no obstacles, based on the depth data in the current initial state, the detection range in the vertical direction is initially divided into multiple detection planes in the way of equal elongation step distance, and at the same time, the detection time required for each detection plane is determined;

[0021] Step 3: The controller controls the telescopic component to perform an elongation action in stages according to the elongation step distance and the detection time, so as to perform the detection operation on different detection planes section by section from top to bottom;

[0022] After the elongation action in each stage is completed, use the positioning module in each integrated sensor module to collect the spatial coordinate information of the current detection point in the current detection plane and send it to the controller. Use the ultrasonic sensor in each integrated sensor module to collect the obstacle signal around the current detection point in the current detection plane and send it to the controller. Use the hydrogen sulfide electrochemical sensor in each integrated sensor module to collect the hydrogen sulfide gas concentration signal of the current detection point in the current detection plane in real time and send it to the controller. Use the oxygen optical sensor in each integrated sensor module to collect the oxygen concentration signal of the current detection point in the current detection plane in real time and send it to the controller;

[0023] The controller obtains the obstacle data around the current detection point in the current detection plane based on the obstacle signal around the current detection point in the current detection plane, obtains the hydrogen sulfide gas concentration data of the current detection plane based on the hydrogen sulfide gas concentration signal of the current detection point in the current detection plane, obtains the oxygen concentration data of the current detection plane based on the oxygen concentration signal of the current detection point in the current detection plane, and records and stores the data;

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

[0025] After completing the detection operations for the detection range in the entire vertical direction, the controller sends the spatial coordinate information of each detection point in each detection plane, the obstacle data around each detection point in each detection plane, the hydrogen sulfide gas concentration data of each detection point in each detection plane, and the oxygen concentration data of each detection point in each detection plane to the data processing terminal located in the control center through the communication module.

[0026] Step 4: The data processing terminal summarizes the obstacle data around each detection point in each detection plane and the spatial coordinate information of each detection point in each detection plane received, and uses the built-in three-dimensional reconstruction module to generate the obstacle coordinate constraint conditions around the detection position. At the same time, the data processing terminal correspondingly summarizes the hydrogen sulfide gas concentration data and oxygen concentration data of each detection point in each detection plane received to obtain the toxic gas concentration distribution data at each detection point in different detection planes in the vertical direction. At the same time, based on the toxic gas concentration distribution data at each detection point in different detection planes, the built-in three-dimensional concentration distribution prediction module uses the interpolation algorithm to construct a three-dimensional gas concentration distribution model with a resolution less than or equal to 0.1 m in the vertical direction of the confined space, and combines the obstacle coordinate constraint conditions to generate an accurate vertical gradient distribution map in the three-dimensional gas concentration distribution model. At the same time, taking 19.5% oxygen concentration and 7 ppm hydrogen sulfide concentration as the critical values, the red area and the green area are marked in the vertical direction. When the oxygen concentration content in any area is lower than 19.5% or the hydrogen sulfide concentration is greater than 7 ppm, it is divided into the red restricted area and the red area is displayed in the three-dimensional gas concentration distribution model. At the same time, the area coordinates are marked in the red area. When the oxygen concentration content in any area is higher than or equal to 19.5% or the hydrogen sulfide concentration is lower than or equal to 7 ppm, it is divided into the green safety area and the green area is displayed in the three-dimensional gas concentration distribution model.

[0027] In order to achieve the vertical gradient detection of the toxic gas concentration and the precise division of the dangerous area, in Step 4, the interpolation algorithm is the Kriging interpolation algorithm, and in the process of constructing the three-dimensional gas concentration distribution model using the interpolation algorithm, the predicted concentration value C(Z0) at any position Z0 in the adjacent detection layers is calculated according to formula (1). pre ;

[0028]

[0029] In the formula, d(Z i ,Z0) is the vertical distance between the known point Z i and the interpolation point Z0, where Z i is the detection plane above the position where Z0 is located; is the known point Z iThe absolute value of the concentration gradient at the location; α is the gradient sensitivity coefficient, which is dynamically adjusted according to the hydrogen sulfide / oxygen concentration threshold. The traditional Kriging method relies on the semi-variogram to calculate weights. The present invention innovatively adjusts the gradient-sensitive weights and directly incorporates the influence of the concentration gradient through the attenuation term to simplify the calculation process and the amount of calculation, and improve the calculation efficiency. In the high-gradient area (such as near the toxic gas leakage point), the gradient term automatically reduces the weights of the points at a long distance and preferentially relies on the adjacent data, meeting the requirements of adaptive sampling and facilitating the acquisition of more accurate calculation results. At the same time, according to the continuous detection requirements in the spatial vertical direction, the present invention innovatively focuses in the vertical direction and only needs to calculate the vertical distance d(Z i , Z0), ignoring the horizontal direction differences, adapting to the vertical layer interpolation scenario, and at the same time, facilitating the further reduction of the calculation process and the amount of calculation, and further improving the calculation efficiency. Furthermore, the present invention innovatively adopts dynamic coefficient adaptation: the coefficient α can be adjusted according to the gradient thresholds of hydrogen sulfide (3 ppm / 0.5 m) or oxygen (5% VOL / 0.5 m) to achieve parametric adaptation, which is conducive to constructing a more accurate complete gas concentration gradient distribution model.

[0030] As a preference, in step three, when the oxygen concentration is lower than 19.5% or the hydrogen sulfide concentration is greater than 7 ppm, the controller controls the alarm to perform an audible and visual alarm action to effectively remind the relevant personnel.

[0031] The present invention overcomes the deficiencies of the prior art and provides a method for detecting the gradient of toxic gases in a confined space based on a telescopic probe. By electrically controlling the telescopic assembly to extend and retract in sections in the vertical direction, the method significantly improves the continuous detection ability in the vertical direction of the space. At the same time, it is not necessary for personnel to enter the high-risk area to perform detection operations in person, and the safety factor is high. By integrating a positioning module, a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, and an ultrasonic sensor in the integrated sensor module, the integrated sensor module can have multiple detection functions, and can conveniently collect the spatial coordinates, hydrogen sulfide gas concentration, oxygen gas concentration, depth data from the bottom, and obstacle data of different depth detection planes. Furthermore, it is beneficial to use the interpolation algorithm to construct a three-dimensional gas concentration distribution model with a resolution less than or equal to 0.1 m, and an accurate vertical gradient distribution map can be generated in combination with the obstacle coordinate constraint conditions. The interpolation algorithm can deduce continuous distribution data based on the discrete detection point data obtained from multiple detection planes. At the same time, when the change rate of hydrogen sulfide gas concentration data between adjacent detection planes > 3 ppm / 0.5 m or the oxygen concentration gradient difference > 5% VOL / 0.5 m, the subsequent elongation step distance is automatically modified to half of the previous elongation step distance. Thus, by dynamically adjusting the elongation step distance, the detection density in the abnormal area is significantly improved, the hydrogen sulfide accumulation at the bottom can be accurately captured, and the risk of the deep high-concentration area can be accurately evaluated. The problem of missed detection in the deep layer of traditional single-point detection is solved, and the accuracy of the three-dimensional gas concentration distribution model can be further improved. By introducing the obstacle coordinate constraint conditions, it can be ensured that the generated three-dimensional gas concentration distribution model is consistent with the actual situation inside the confined space, which is beneficial to guiding subsequent operations more safely and effectively. On this basis, with the oxygen concentration of 19.5% and the hydrogen sulfide concentration of 7 ppm as the critical values, a distribution map of the red restricted area and the green safe area in the vertical direction is automatically generated. By marking the concentration mutation area, the limitations of traditional modeling are effectively broken through, providing real-time visual decision support for the operators, which can effectively guide the actions of subsequent personnel during the detection operation, is beneficial to ensuring the safety of the operators, and can greatly reduce the accident risk in the subsequent operation process.

[0032] The implementation process of this method is simple and has a high degree of automation. It innovatively realizes the high-precision gradient detection operation of toxic gases in the vertical direction in a confined space, can obtain a complete gas concentration gradient distribution model in the vertical direction, solves the technical problem that traditional single-point detection cannot accurately identify the gas accumulation situation in the deep dangerous area, significantly improves the efficiency, accuracy, and safety of toxic gas detection in a confined space, and provides reliable safety guarantee for the operators. Description of the Drawings

[0033] Figure 1Schematic diagram of the state for detecting the concentration of toxic gases in a confined space by using an electric telescopic rod in the present invention;

[0034] Figure 2 Principle block diagram of the control part in the present invention;

[0035] Figure 3 Schematic structural diagram of the fully retracted state of the electric telescopic rod in the present invention;

[0036] Figure 4 Schematic structural diagram of the fully extended state of the electric telescopic rod in the present invention;

[0037] Figure 5 Schematic structural diagram of the integrated sensor module in the present invention;

[0038] Figure 6 Schematic diagram of the method for obtaining the critical values of hydrogen sulfide and oxygen concentrations when demarcating the red and green areas in the vertical direction of a confined space.

[0039] In the figure: 1. Electric telescopic rod, 1-1. Main rod body, 1-2. First-stage telescopic rod, 1-3. Second-stage telescopic rod; 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. Confined space; 4. Cross bracket. Specific implementation manners

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

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

[0042] The electric telescopic rod 1 includes a telescopic assembly and an electric drive mechanism. The telescopic assembly includes a main rod body 1-1, a first-stage telescopic rod 1-2 arranged in the main rod body 1, and a second-stage telescopic rod 1-3 arranged in the first-stage telescopic rod 1-2; the electric drive mechanism is installed inside the main rod body 1-1 and is connected to the first-stage telescopic rod 1-2 and the second-stage telescopic rod 1-3 through an internal linkage mechanism for driving the second-stage telescopic rod 1-3 and the first-stage telescopic rod 1-2 to perform elongation and retraction actions axially in sequence; wherein, the first-stage telescopic rod 1-2 can only move axially relative to the main rod body 1 and will not rotate radially, and the second-stage telescopic rod 1-3 can only move axially relative to the first-stage telescopic rod 1-2 and will not rotate radially;

[0043] The cross support 4 is horizontally arranged, and an installation hole is provided at its center. The cross support 4 is fixedly sleeved outside the end of the secondary telescopic rod 1-3 through the installation hole.

[0044] The number of the integrated sensor modules 2 is nine. Among them, four integrated sensor modules 2 are respectively and fixedly installed below the four ends of the cross support 4, one integrated sensor module 2 is fixedly installed below the center of the cross support 4, and four integrated sensor modules 2 are respectively and fixedly installed below the middle sections of the four arms; the integrated sensor module 2 includes a hydrogen sulfide electrochemical sensor 2-1, an oxygen optical sensor 2-2, a laser ranging module 2-3, and a ultrasonic sensor 2-4.

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

[0046] In order to facilitate obtaining the spatial coordinate information of each detection plane, the integrated sensor module 2 further includes a positioning module 2-5.

[0047] In order to ensure the control accuracy during the telescopic process and, at the same time, to effectively ensure the service life of the electric telescopic rod, the electric drive mechanism is a stepping motor; the electric telescopic rod 1 is made of carbon fiber composite material, and the corrosion resistance level is IP68; the telescopic accuracy of the electric telescopic rod 1 is 0.1 m, and its telescopic accuracy error ≤ ±0.05 m. The electric telescopic rod in the present invention can adopt the electric telescopic rod in the prior art.

[0048] In order to facilitate the interaction and communication with external devices and, at the same time, to facilitate the warning action in time when a dangerous situation is found, a communication module and an alarm are further included. The communication module and the alarm are both installed on the electric telescopic rod 1 and are both connected to the controller. As a preference, a power supply module is further included, and the power supply module is used for power supply.

[0049] In order to facilitate the interaction and communication with the controller and, at the same time, to analyze and process the detection data sent by the controller, a data processing terminal is further included. The data processing terminal is installed in the control center and is connected to the controller by means of wireless communication or wired communication.

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

[0051] As a preference, the controller is a PLC controller.

[0052] In the present invention, a telescopic assembly with a multi-stage telescopic rod is adopted as the support body of the integrated sensor module. At the same time, an electric drive mechanism is used to drive the telescopic assembly to extend and retract, so that the downward penetration depth of the integrated sensor module can be accurately controlled. Furthermore, detection operations at different depths can be achieved in the vertical direction, and at the same time, the continuous detection ability in the vertical direction of space is significantly improved. By installing a cross bracket at the lower end of the electric telescopic rod, and then installing a plurality of integrated sensor modules at intervals at the lower end of the cross bracket, it is convenient to effectively expand the coverage range of the detection area through the cross bracket. By integrating a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, and an ultrasonic sensor in the integrated sensor module, on the one hand, the hydrogen sulfide concentration and oxygen concentration at different depth detection planes can be synchronously detected. Thus, the hydrogen sulfide concentration and oxygen concentration data at each detection plane at different depths within the entire detection range can be comprehensively sensed. Furthermore, it is beneficial to construct a complete gas concentration gradient distribution model in the vertical direction by using the detection data at each detection plane, greatly improving the safety guarantee ability during the operation in a confined space. On the other hand, the initial detection depth can be detected through the laser ranging module, which is beneficial to preliminarily determine the elongation step distance according to the detection depth. At the same time, the obstacle data around each detection plane can be obtained through the ultrasonic sensor, which is beneficial to form the obstacle coordinate constraint conditions around the detection position according to the obstacle data around each detection plane. Further, after constructing a three-dimensional gas concentration distribution model subsequently, an accurate vertical gradient distribution map can be generated in combination with the obstacle coordinate constraint conditions, so as to more effectively guide the subsequent detection actions of personnel entering the detection operation environment and be beneficial to ensuring the personal safety of the operators.

[0053] The system has a simple structure, low manufacturing cost, high automation degree, high safety factor, and is convenient to carry and use. It can automatically achieve high-precision gradient detection of toxic gases in the vertical direction within a confined space, without the need for operators to personally enter high-risk areas to perform detection operations, solving the technical problem that traditional single-point detection cannot identify deep dangerous areas, significantly improving the efficiency and safety of toxic gas detection in confined spaces, and providing reliable safety guarantees for operators.

[0054] The present invention also provides a method for detecting the gradient of toxic gases in a confined space based on a telescopic probe rod. By using a system for detecting the gradient of toxic gases in a confined space based on a telescopic probe rod, the method includes the following steps:

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

[0056] Step 2: Use the laser ranging module 2-3 in each integrated sensor module 2 to collect the depth signal from the cross bracket 4 to the bottom of the confined space 3 in the initial state and send it to the controller; the controller obtains the corresponding depth data based on the depth signals sent by each integrated sensor module 2, and determines whether there are obstacles within the coverage range of the cross bracket 4 based on the obtained depth data. When there are obstacles, re-execute Step 1 to re-select the detection position. When there are no obstacles, based on the depth data in the current initial state, the detection range in the vertical direction is initially divided into multiple detection planes in the way of equal elongation step distance. For example, it can be the 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 in sequence. At the same time, determine the detection time required for each detection plane;

[0057] Step 3: The controller controls the telescopic assembly to perform an elongation action in stages according to the elongation step distance and the 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) section by section from top to bottom;

[0058] After the elongation action in each stage is completed, use the positioning module 2-5 in each integrated sensor module 2 to collect the spatial coordinate information of the current detection point in the current detection plane and send it to the controller, use the ultrasonic sensor 2-4 in each integrated sensor module 2 to collect the obstacle signal around the current detection point in the current detection plane and send it to the controller, use the hydrogen sulfide electrochemistry sensor 2-1 in each integrated sensor module 2 to collect the hydrogen sulfide gas concentration signal of the current detection point in the current detection plane in real time and send it to the controller, and use the oxygen optical sensor 2-2 in each integrated sensor module 2 to collect the oxygen concentration signal of the current detection point in the current detection plane in real time and send it to the controller;

[0059] The controller obtains the obstacle data around the current detection point in the current detection plane based on the obstacle signal around the current detection point in the current detection plane, obtains the hydrogen sulfide gas concentration data of the current detection plane based on the hydrogen sulfide gas concentration signal of the current detection point in the current detection plane, obtains the oxygen concentration data of the current detection plane based on the oxygen concentration signal of the current detection point in the current detection plane, and records and stores the data;

[0060] After the detection operations on two detection planes are completed, the hydrogen sulfide gas concentration data and oxygen concentration data of the vertically corresponding detection points between two adjacent detection planes are compared. When the change rate of the hydrogen sulfide gas concentration data > 3 ppm / 0.5 m or the oxygen concentration gradient difference > 5% VOL / 0.5 m, the elongation step distance in the subsequent stage is modified to half of the previous elongation step distance. Thus, the sampling density of the abnormal area can be effectively increased, which is beneficial to ensuring a more accurate three-dimensional gas concentration distribution model. Otherwise, the elongation step distance is not modified;

[0061] After the detection operations within the detection range in the entire vertical direction are completed, 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 around each detection point on each detection plane and the spatial coordinate information of each detection point on each detection plane received, and uses the built-in three-dimensional reconstruction module to generate the obstacle coordinate constraint conditions around the detection position. At the same time, the data processing terminal correspondingly summarizes the hydrogen sulfide gas concentration data and oxygen concentration data of each detection point on each detection plane received to obtain the toxic gas concentration distribution data of each detection point in different detection planes in the vertical direction. At the same time, based on the toxic gas concentration distribution data of each detection point in different detection planes, the built-in three-dimensional concentration distribution prediction module uses the interpolation algorithm to construct a three-dimensional gas concentration distribution model with a resolution less than or equal to 0.1 m (preferably 0.05 m) in the vertical direction of the confined space 3, and generates an accurate vertical gradient distribution map in the three-dimensional gas concentration distribution model in combination with the obstacle coordinate constraint conditions; At the same time, taking 19.5% oxygen concentration and 7 ppm hydrogen sulfide concentration as the critical values, the red area and the green area are marked in the vertical direction. When the oxygen concentration content in any area is lower than 19.5% or the hydrogen sulfide concentration is greater than 7 ppm, it is classified as a red restricted area (high-concentration hydrogen sulfide restricted area, low-oxygen restricted area), and the red area is displayed in the three-dimensional gas concentration distribution model. At the same time, the area coordinates are marked in the red area. When the oxygen concentration content in any area is higher than or equal to 19.5% or the hydrogen sulfide concentration is lower than or equal to 7 ppm, it is classified as a green safety area (safe operation area), and the green area is displayed in the three-dimensional gas concentration distribution model. The specific classification method is as Figure 6 shown.

[0063] In order to achieve the vertical gradient detection of the concentration of toxic gases and the precise division of dangerous areas, in Step 4, the interpolation algorithm is the Kriging interpolation algorithm. During the process of constructing the three-dimensional gas concentration distribution model using the interpolation algorithm, the predicted concentration value C(Z0) at any position Z0 in adjacent detection levels is calculated according to formula (1). pre ;

[0064]

[0065] In the formula, d(Z i ,Z0) is the vertical distance between the known point Z i and the point to be interpolated Z0, where Z i is the detection plane above the position where Z0 is located; is the absolute value of the concentration gradient at the known point Z i ; α is the gradient sensitivity coefficient, which is dynamically adjusted according to the hydrogen sulfide / oxygen concentration threshold. Preferably, the gradient sensitivity coefficient of hydrogen sulfide is 0.5, and the gradient sensitivity coefficient of oxygen is 0.3. The traditional Kriging method relies on the semi-variogram to calculate the weights. The present invention innovatively adjusts the gradient sensitivity weights and directly incorporates the influence of the concentration gradient through the attenuation term , simplifies the calculation process and the amount of calculation, and improves the calculation efficiency. In high-gradient regions (such as near the toxic gas leakage point), the gradient term automatically reduces the weights of distant points and preferentially relies on adjacent data, meeting the requirements of adaptive sampling and facilitating the acquisition of more accurate calculation results. At the same time, according to the continuous detection requirements in the spatial vertical direction, the present invention innovatively focuses in the vertical direction and only needs to calculate the vertical distance d(Z i ,Z0), ignoring the horizontal direction differences, adapting to the vertical layer interpolation scenario, and at the same time, facilitating further reduction of the calculation process and the amount of calculation, and further improving the calculation efficiency. Moreover, the present invention innovatively adopts dynamic coefficient adaptation: the coefficient α can be adjusted according to the gradient thresholds of hydrogen sulfide (3 ppm / 0.5 m) or oxygen (5% VOL / 0.5 m) to achieve parametric adaptation, which is beneficial to constructing a more accurate complete gas concentration gradient distribution model.

[0066] As a preference, in Step 3, when the oxygen concentration is lower than 19.5% or the hydrogen sulfide concentration is greater than 7 ppm, the controller controls the alarm to perform an audible and visual alarm action to effectively remind relevant personnel.

[0067] The present invention overcomes the deficiencies of the prior art and provides a method for detecting the gradient of toxic gases in a confined space based on a telescopic probe. By telescopically extending and retracting the telescopic component in sections in the vertical direction through electric control, the continuous detection ability in the vertical direction of the space is significantly improved. At the same time, there is no need for personnel to personally enter high-risk areas to perform detection operations, and the safety factor is high. By integrating a positioning module, a hydrogen sulfide electrochemical sensor, an oxygen optical sensor, a laser ranging module, and an ultrasonic sensor in the integrated sensor module, the integrated sensor module can have multiple detection functions, and can conveniently collect the spatial coordinates, hydrogen sulfide gas concentration, oxygen gas concentration, depth data from the bottom, and obstacle data of different depth detection planes. Furthermore, it is beneficial to use an interpolation algorithm to construct a three-dimensional gas concentration distribution model with a resolution less than or equal to 0.1 m, and an accurate vertical gradient distribution map can be generated in combination with the obstacle coordinate constraint conditions. The interpolation algorithm can be used to deduce continuous distribution data based on the discrete detection point data obtained from multiple detection planes. At the same time, when the change rate of the hydrogen sulfide gas concentration data between adjacent detection planes > 3 ppm / 0.5 m or the oxygen concentration gradient difference > 5% VOL / 0.5 m, the subsequent elongation step distance is automatically modified to half of the previous elongation step distance. Thus, by dynamically adjusting the elongation step distance, the detection density in the abnormal area is significantly improved, the accumulation of hydrogen sulfide at the bottom can be accurately captured, and the risk of high-concentration areas in the deep part can be accurately evaluated. The problem of deep undetected leakage in traditional single-point detection is solved, and the accuracy of the three-dimensional gas concentration distribution model can be further improved. By introducing the obstacle coordinate constraint conditions, it can be ensured that the generated three-dimensional gas concentration distribution model is consistent with the actual situation inside the confined space, which is beneficial to guiding subsequent operations more safely and effectively. On this basis, taking the oxygen concentration of 19.5% and the hydrogen sulfide concentration of 7 ppm as the critical values, a distribution map of the red restricted area and the green safety area in the vertical direction is automatically generated. By marking the concentration mutation area, the limitations of traditional modeling are effectively broken through, providing real-time visual decision support for the operators, which can effectively guide the actions of subsequent personnel during the detection operation, is beneficial to ensuring the safety of the operators, and can greatly reduce the accident risk during the subsequent operation process.

[0068] The implementation process of this method is simple and has a high degree of automation. It innovatively realizes the high-precision gradient detection operation of toxic gases in the vertical direction in a confined space, can obtain a complete gas concentration gradient distribution model in the vertical direction, solves the technical problem that traditional single-point detection cannot accurately identify the gas accumulation situation in deep dangerous areas, significantly improves the efficiency, accuracy, and safety of toxic gas detection in confined spaces, and provides reliable safety guarantees for the operators.

Claims

1. A limited space toxic gas gradient detection system based on a telescopic probe rod, comprising an electric telescopic rod (1), characterized in that, It also includes a cross bracket (4), an integrated sensor module (2) and a controller; The electric telescopic rod (1) includes a telescopic component and an electric drive mechanism. The telescopic component includes a main rod body (1-1), a first-stage telescopic rod (1-2) arranged inside the main rod body (1), and a second-stage telescopic rod (1-3) arranged inside the first-stage telescopic rod (1-2); The electric drive mechanism is installed inside the main rod body (1-1) and is connected to the first-stage telescopic rod (1-2) and the second-stage telescopic rod (1-3) through an internal linkage mechanism, and is used to drive the second-stage telescopic rod (1-3) and the first-stage telescopic rod (1-2) to perform axial extension and retraction actions one by one; The cross bracket (4) is horizontally arranged, and an installation hole is opened in the center thereof, and it is fixedly sleeved outside the end of the second-stage telescopic rod (1-3) through the installation hole; The number of the integrated sensor modules (2) is 9. Among them, 4 integrated sensor modules (2) are respectively 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 respectively fixedly installed below the middle sections of the 4 arms; The integrated sensor module (2) includes a hydrogen sulfide electrochemical sensor (2-1), an oxygen optical sensor (2-2), a laser ranging module (2-3) and an ultrasonic sensor (2-4); The controller is respectively connected to the electric drive mechanism and the integrated sensor module (2).

2. The limited space toxic gas gradient detection system based on a telescopic probe rod according to claim 1, wherein, The integrated sensor module (2) also includes a positioning module (2-5).

3. A limited space toxic gas gradient detection system based on a telescopic probe rod according to claim 1, characterized in that, The electric drive mechanism is a stepping motor; the electric telescopic rod (1) is made of carbon fiber composite material, and the corrosion resistance level is IP68; the telescopic accuracy of the electric telescopic rod (1) is 0.1 m, and its telescopic accuracy error ≤ ±0.05 m.

4. A gradient detection system for toxic gases in a confined space based on a telescopic probe rod according to claim 1, characterized in that It also includes a communication module and an alarm. The communication module and the alarm are both installed on the electric telescopic rod (1) and are both connected to the controller.

5. The limited space toxic gas gradient detection system based on a telescopic probe rod according to claim 1, wherein It also includes a data processing terminal. The data processing terminal is installed in the control center and is connected to the controller by means of wireless communication or wired communication.

6. The limited space toxic gas gradient detection system based on a telescopic probe rod according to claim 1, characterized in that, The measurement range of the hydrogen sulfide electrochemical sensor (2-1) is 0-100 ppm, the response time ≤ 5 s, the measurement accuracy of the oxygen optical sensor (2-2) is ±0.5%VOL, and the measurement range of the laser ranging module (2-3) is 0.1-20 m.

7. A limited space toxic gas gradient detection system based on a telescopic probe rod according to claim 1, characterized in that, The controller is a PLC controller.

8. A method for detecting the gradient of toxic gases in a confined space based on a telescopic probe rod, which uses a system for detecting the gradient of toxic gases in a confined space based on a telescopic probe rod as described in claim 3, characterized in that, It includes the following steps: Step 1: Select a detection position in the confined space (3) to be detected, and vertically fix the electric telescopic rod (1) at the top of the detection position. At the same time, ensure that the telescopic component is in a fully retracted state in the initial state; Step 2: Use the laser ranging module (2-3) in each integrated sensor module (2) to collect the depth signal from the cross bracket (4) to the bottom of the confined space (3) in the initial state and send it to the controller; the controller obtains the corresponding depth data based on the depth signals sent by each integrated sensor module (2), and determines whether there are obstacles within the coverage range of the cross bracket (4) based on the obtained depth data. When there are obstacles, re-execute Step 1 to re-select the detection position. When there are no obstacles, based on the depth data in the current initial state, the detection range in the vertical direction is initially divided into multiple detection planes in the manner of equal elongation step distances, and at the same time, the detection time required for each detection plane is determined; Step 3: The controller controls the telescopic assembly to perform an elongation action in stages according to the elongation step distance and the detection time, so as to perform the detection operations on different detection planes one by one from top to bottom; After the elongation action in each stage is completed, use the positioning module (2-5) in each integrated sensor module (2) to collect the spatial coordinate information of the current detection point in the current detection plane and send it to the controller. Use the ultrasonic sensor (2-4) in each integrated sensor module (2) to collect the obstacle signals around the current detection point in the current detection plane and send it to the controller. Use the hydrogen sulfide electrochemical sensor (2-1) in each integrated sensor module (2) to collect the hydrogen sulfide gas concentration signal of the current detection point in the current detection plane in real time and send it to the controller. Use the oxygen optical sensor (2-2) in each integrated sensor module (2) to collect the oxygen concentration signal of the current detection point in the current detection plane in real time and send it to the controller; The controller obtains the obstacle data around the current detection point in the current detection plane based on the obstacle signals around the current detection point in the current detection plane, obtains the hydrogen sulfide gas concentration data of the current detection point in the current detection plane based on the hydrogen sulfide gas concentration signal of the current detection point in the current detection plane, obtains the oxygen concentration data of the current detection point in the current detection plane based on the oxygen concentration signal of the current detection point in the current detection plane, and records and stores the data; After the detection operations on two detection planes are completed, compare the hydrogen sulfide gas concentration data and the oxygen concentration data of the vertically corresponding detection points of two adjacent detection planes. When the change rate of the hydrogen sulfide gas concentration data > 3 ppm / 0.5 m or the oxygen concentration gradient difference > 5% VOL / 0.5 m, modify the elongation step distance in the subsequent stage to half of the previous elongation step distance; otherwise, do not modify the elongation step distance; After the detection operations on the entire detection range in the vertical direction are completed, the controller sends the spatial coordinate information of each detection point in each detection plane, the obstacle data around each detection point in each detection plane, the hydrogen sulfide gas concentration data of each detection point in each detection plane, and the oxygen concentration data of each detection point in each detection plane to the data processing terminal located in the control center through the communication module Step 4: The data processing terminal aggregates the obstacle data around each detection point of each detection plane and the spatial coordinate information of each detection point of each detection plane it receives, and uses the built-in three-dimensional reconstruction module to generate the obstacle coordinate constraint conditions around the detection position. At the same time, the data processing terminal correspondingly aggregates the hydrogen sulfide gas concentration data and oxygen concentration data of each detection point of each detection plane it receives to obtain the toxic gas concentration distribution data of each detection point in different detection planes in the vertical direction. At the same time, based on the toxic gas concentration distribution data of each detection point in different detection planes, the built-in three-dimensional concentration distribution prediction module uses the interpolation algorithm to construct a three-dimensional gas concentration distribution model with a resolution less than or equal to 0.1 m in the vertical direction of the confined space (3), and generates an accurate vertical gradient distribution map in the three-dimensional gas concentration distribution model in combination with the obstacle coordinate constraint conditions. At the same time, taking 19.5% oxygen concentration and 7 ppm hydrogen sulfide concentration as the critical values, the red area and green area are marked in the vertical direction. When the oxygen concentration content in any area is lower than 19.5% or the hydrogen sulfide concentration is greater than 7 ppm, it is classified as a red restricted area and the red area is displayed in the three-dimensional gas concentration distribution model. At the same time, the area coordinates are marked in the red area. When the oxygen concentration content in any area is higher than or equal to 19.5% or the hydrogen sulfide concentration is lower than or equal to 7 ppm, it is classified as a green safety area and the green area is displayed in the three-dimensional gas concentration distribution model.

9. A method for detecting the gradient of toxic gases in a confined space based on a telescopic probe rod according to claim 8, characterized in that In step four, the interpolation algorithm is the Kriging interpolation algorithm, and in the process of constructing the three-dimensional gas concentration distribution model using the interpolation algorithm, the predicted concentration value C(Z0) at any position Z0 in adjacent detection levels is calculated according to formula (1). pre ; Where, d(Z i , Z0) is the vertical distance between the known point Z i and the point Z0 to be interpolated, where Z i is the detection plane above the position where Z0 is located; |▽C i | is the absolute value of the concentration gradient at the known point Z i ; α is the gradient sensitivity coefficient, which is dynamically adjusted according to the hydrogen sulfide / oxygen concentration threshold.

10. A method for detecting the gradient of toxic gases in a confined space based on a telescopic probe rod according to claim 8 or 9, characterized in that, In Step 3, when the oxygen concentration content is lower than 19.5% or the hydrogen sulfide concentration is greater than 7 ppm, the controller controls the alarm to perform an audible and visual alarm action to effectively remind the relevant personnel.

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