Tunnel construction gas detection device and use method thereof

Abstract

The invention discloses a tunnel construction gas detection device and a use method thereof, and relates to the technical field of tunnel construction safety detection. The device comprises a machine body, a gas detection unit is arranged in the machine body, a detection part in the gas detection unit is slidably arranged in a guide seat, a catalytic combustion sensor and an infrared gas sensor in the detection part are started in turn to detect gas, a moving part is arranged in the machine body, and the moving part is in driving connection with the detection part. The moving part is used for driving the detection part to move back and forth in the guide seat. According to the device, the catalytic combustion sensor and the infrared gas sensor are started in turn, the approximate gas leakage area is rapidly positioned by using the catalytic combustion sensor, and then the gas concentration is accurately measured by using the infrared gas sensor, so that the gas leakage point can be rapidly and accurately positioned, and the detection precision and efficiency are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction safety detection, and in particular to a tunnel construction gas detection device and a use method thereof. Background Art

[0002] During tunnel construction, complex geological conditions may generate various flammable gases, such as methane. Once these gases leak and reach a certain concentration, they can easily cause safety accidents such as explosions and fires, seriously threatening the lives of construction workers and project progress.

[0003] Existing detection devices present significant difficulties in locating gas leaks. Some devices can only detect the presence of gas but cannot pinpoint its exact location. Furthermore, existing tunnel construction gas detection equipment has a limited detection range and cannot cover the entire tunnel construction area. This results in gas leaks within the tunnel remaining undetected, presenting limitations.

[0004] The reason for this problem is that when a combustible gas leak is detected in the tunnel, construction workers need to spend a lot of time and energy to investigate because they cannot accurately know the location of the leak point. This not only delays the construction progress but also increases safety risks. Existing fixed gas detection devices are usually installed at specific locations in the tunnel and can only detect local areas around them, but cannot detect the entire tunnel. Although some other portable detection devices can be carried to different locations for detection, they require construction workers to frequently move the detection location, increasing the workload and difficulty of detection. Therefore, we propose a tunnel construction gas detection device and its use method to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention provides a tunnel construction gas detection device and its use method, which address the significant difficulties existing detection devices face in locating gas leaks. Some devices can only detect the presence of gas but cannot pinpoint the specific location of the leak. Furthermore, existing tunnel construction gas detection devices have a limited detection range and cannot cover the entire tunnel construction area. This results in gas leaks within the tunnel remaining undetected, creating limitations.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A tunnel construction gas detection device and a method of using the same, comprising a body, the body being assembled from a guide seat and a fixed column, the body being internally provided with a gas detection unit, the gas detection unit comprising a detection member and a moving member;

[0007] The detection member is slidably arranged inside the guide seat, and the detection member includes a catalytic combustion sensor, an infrared gas sensor and a processor;

[0008] The catalytic combustion sensor and the infrared gas sensor are activated in turn to detect gas. The catalytic combustion sensor is used to locate the approximate area of ​​gas leakage, and the infrared gas sensor is used to accurately measure gas concentration and transmit the data to the processor. The processor accurately locates the leakage point according to the step-by-step change of gas concentration and triggers the alarm unit.

[0009] The moving member is arranged inside the machine body, is drivingly connected to the detecting member, and is used to drive the detecting member to perform a reciprocating motion inside the guide seat.

[0010] Preferably, a protective shell is provided on the outer surface of the catalytic combustion sensor and the infrared gas sensor, and a heat insulation block is provided inside the protective shell, and the heat insulation block is used to separate the catalytic combustion sensor and the infrared gas sensor.

[0011] Preferably, a fixed block is provided on one side of the protective shell, an air pump is provided inside the fixed block, the top of the air pump is connected to an air intake pipe, the air intake pipe is respectively connected to the catalytic combustion sensor and the infrared gas sensor, and an electromagnetic valve is provided at the connection between the air intake pipe and the catalytic combustion sensor and the infrared gas sensor, and the electromagnetic valve is used to control the air pump to exhaust a certain sensor.

[0012] Preferably, a first air chamber is opened inside the catalytic combustion sensor, a first filter is provided at the bottom of the catalytic combustion sensor, an air permeable plate is provided above the first filter, and the air permeable plate is fixedly assembled to the inner wall of the first air chamber.

[0013] Preferably, a wire post is fixedly installed below the breathable plate, and the wire posts are symmetrically arranged. A ceramic post is arranged below the breathable plate, and wires are wound around the outer surfaces of the wire post and the ceramic post, and the wire post and the ceramic post are electrically connected through the wires.

[0014] Preferably, a second air chamber is provided inside the infrared gas sensor, an air inlet is provided on one side of the infrared gas sensor, a second filter is fixedly installed inside the air inlet, a light-emitting component is provided at the lower end of the interior of the second air chamber, and a receiving component is provided at the upper end of the interior of the second air chamber.

[0015] Preferably, the moving part includes a servo motor, a driving sprocket, a connecting column, a driven sprocket, a supporting wheel and a rotating column;

[0016] The servo motor is fixedly assembled on one side of the guide seat; the driving sprocket is arranged at both ends of the guide seat; the connecting column is fixedly assembled inside the driving sprocket, and the connecting column and the servo motor are fixedly assembled; the driven sprocket is arranged at both ends of the other side of the guide seat; the supporting wheel is arranged between the driving sprocket and the driven sprocket; the rotating column is fixedly assembled inside the driven sprocket and the supporting wheel respectively, and the rotating column is rotatably connected to the guide seat.

[0017] Preferably, the moving member further comprises a chain, a fixed plate, a guide block, a guide groove and a pulley;

[0018] The chain is sleeved on the outer surfaces of the driving sprocket, the driven sprocket and the support wheel, and the chain is meshed with the driving sprocket, the driven sprocket and the support wheel; the fixed plate is fixedly assembled with the chain, and the fixed block is fixedly assembled at the bottom of the fixed plate; the guide block is fixedly assembled at both ends inside the guide seat; the guide groove is opened inside the guide block; the pulley is arranged at both ends of the bottom of the fixed plate, and the pulley is slidably connected inside the guide groove.

[0019] Preferably, the calculation model of the processor is as follows:

[0020] 1. Drive control model

[0021] Assume the tunnel length is L, the driving member motion speed function is:

[0022]

[0023]

[0024] Position function:

[0025]

[0026] Indicates that time t is in a specific detection stage;

[0027] V(t) is the velocity as a function of time;

[0028] V(0): speed in the initial detection phase;

[0029] V(1): speed of the precise detection stage;

[0030] dt is the differential symbol in calculus, representing an infinitesimal increment of time;

[0031] The position function x(t) is obtained by integrating the velocity function:

[0032]

[0033] dt: integral variable, representing a small change in time t;

[0034] dt is used in the integration to accumulate the change of acceleration over time, and finally obtain the position x(t) of the driving member.

[0035] 2. Dual Sensor Fusion Detection Model

[0036] 1. Rough detection stage (catalytic combustion type):

[0037]

[0038] 2. Precision detection stage (infrared sensor):

[0039]

[0040] G(x): output signal of the sensor at position x

[0041] K1: reflects the response intensity of the sensor to combustible gas and is related to the efficiency of the catalytic combustion reaction;

[0042] a: describes the exponential decay characteristics of gas concentration as it spreads from the leak point, which is related to the tunnel ventilation conditions;

[0043] ε1 ~ N(0, σ1²): measurement noise with mean 0 and variance Normal distribution;

[0044] H(x): output signal of the sensor at position x

[0045] K2: related to the infrared absorption cross section of gas molecules, which determines the selectivity of the sensor to specific gases;

[0046] : nonlinear saturation coefficient;

[0047] ε2 ~ N(0, σ2²): measurement noise, with mean 0 and variance Normal distribution;

[0048] 3. Leakage Area Location Algorithm

[0049] Based on the gradient ascent method:

[0050]

[0051] Define suspicious areas:

[0052] : The position corresponding to the maximum value of the catalytic combustion detector signal gradient;

[0053] : half width of the suspicious area;

[0054] Physical meaning;

[0055]

[0056]

[0057] 4. Concentration Field Reconstruction Model

[0058] Use Gaussian kernel density estimation:

[0059]

[0060] The concentration field was reconstructed by Gaussian kernel density estimation;

[0061] h: kernel function bandwidth

[0062] Controlling the smoothness of the concentration field requires satisfying the sampling theorem

[0063] Gaussian kernel function:

[0064] Function: Discrete infrared sensor measurement value Smooth interpolation to a continuous concentration field.

[0065] 5. Accurately locate the leakage point

[0066] Solve for the maximum concentration gradient:

[0067]

[0068] Leakage point:

[0069] Reconstructing the spatial gradient of the concentration field

[0070] Calculation method:

[0071]

[0072]

[0073] 6. Alarm triggering conditions

[0074] When satisfied:

[0075]

[0076] The alarm system is triggered

[0077] Model parameter optimization:

[0078]

[0079] C_threshold = 5%LEL: combustible gas concentration alarm threshold;

[0080] ∇C_threshold = 2%(LEL / m): Concentration gradient alarm threshold.

[0081] Preferably, the method comprises the following steps:

[0082] Step 1: Start the catalytic combustion sensor, drive it to move back and forth inside the guide seat through the moving part, and detect the combustible gas in real time;

[0083] Step 2: The catalytic combustion sensor detects the combustible gas leak and locates the approximate area of ​​the gas leak;

[0084] Step 3: Switch to the infrared gas sensor. When the moving part is in the gas leakage area, the infrared gas sensor will continue to detect the concentration of the leaked gas and transmit the real-time data to the processor.

[0085] Step 4: The processor accurately locates the leakage point according to the change in gas leakage concentration and triggers the alarm device.

[0086] The present invention discloses a tunnel construction gas detection device and a method of using the same, which have the following beneficial effects:

[0087] 1. The device uses the catalytic combustion sensor and the infrared gas sensor to start up in turn. It first uses the catalytic combustion sensor to quickly locate the approximate area of ​​gas leakage, and then uses the infrared gas sensor to accurately measure the gas concentration. It can quickly and accurately locate the gas leakage point, thereby improving detection accuracy and efficiency.

[0088] 2. The device can effectively protect the catalytic combustion sensor and infrared gas sensor by setting up a protective shell and a heat insulation block, avoiding them from being affected by the external environment and extending the service life of the sensor.

[0089] 3. Through the setting of the moving parts, the device can drive the detection part to move back and forth inside the guide seat, thereby expanding the detection range, improving the comprehensiveness of the detection, and meeting the needs of users. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0091] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0092] Figure 2 This is a schematic diagram of the side structure of the machine body of the present invention;

[0093] Figure 3 This is a schematic diagram of the structure of the moving part of the present invention;

[0094] Figure 4 This is a schematic diagram of the fixed block structure of the present invention;

[0095] Figure 5 This is a schematic diagram of the internal structure of the fixed block of the present invention;

[0096] Figure 6 Schematic diagram of the internal structure of the first air chamber and the second air chamber of the present invention;

[0097] Figure 7 This is a schematic structural diagram of the catalytic combustion sensor of the present invention;

[0098] Figure 8 This is a schematic diagram of the sensor detection process of the present invention;

[0099] Figure 9 This is a flow chart for accurately locating leakage points in the present invention.

[0100] In the figure: 1. body; 11. guide seat; 12. fixed column; 2. gas detection unit; 21. catalytic combustion sensor; 211. first air chamber; 212. first filter; 213. breathable plate; 214. wire column; 215. ceramic column; 216. wire; 22. infrared gas sensor; 221. second air chamber; 222. air inlet; 223. second filter; 224. light-emitting element; 225. receiving element; 23. moving element; 231. servo motor; 232. driving sprocket; 233. connecting column; 234. driven sprocket; 235. supporting wheel; 236. rotating column; 237. chain; 238. fixed plate; 239. guide block; 240. guide groove; 241. pulley; 24. fixed block; 25. vacuum pump; 26. suction pipe; 27. protective shell; 28. insulation block. DETAILED DESCRIPTION

[0101] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0102] The present invention addresses the significant difficulties existing detection devices face in locating gas leaks by providing a tunnel construction gas detection device and its use method. Some devices can only detect the presence of gas but cannot pinpoint the specific location of the leak. Furthermore, existing tunnel construction gas detection devices have a limited detection range and cannot cover the entire tunnel construction area. This results in gas leaks within the tunnel remaining undetected, creating a significant limitation.

[0103] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0104] The embodiment of the present invention discloses a tunnel construction gas detection device and a use method thereof.

[0105] Example 1:

[0106] The embodiment of the present invention discloses a tunnel construction gas detection device and its use method. Figure 1-3 As shown, the machine body 1 is composed of a guide base 11 and a fixed column 12. A gas detection unit 2 is provided inside the machine body 1. The gas detection unit 2 includes a detection part and a moving part 23.

[0107] The detection component is slidably arranged inside the guide seat 11, and the detection component includes a catalytic combustion sensor 21, an infrared gas sensor 22 and a processor;

[0108] The catalytic combustion sensor 21 and the infrared gas sensor 22 are activated in turn to detect gas. The catalytic combustion sensor 21 is used to locate the approximate area of ​​gas leakage, and the infrared gas sensor 22 is used to accurately measure the gas concentration and transmit the data to the processor. The processor accurately locates the leakage point according to the step-by-step change of gas concentration and triggers the alarm unit.

[0109] The moving member 23 is disposed inside the machine body 1 . The moving member 23 is drivingly connected to the detecting member. The moving member 23 is used to drive the detecting member to perform a reciprocating motion inside the guide seat 11 .

[0110] The moving member 23 includes a servo motor 231, a driving sprocket 232, a connecting column 233, a driven sprocket 234, a supporting wheel 235 and a rotating column 236;

[0111] The servo motor 231 is fixedly assembled on one side of the guide seat 11; the driving sprocket 232 is arranged at both ends of the guide seat 11; the connecting column 233 is fixedly assembled inside the driving sprocket 232, and the connecting column 233 is fixedly assembled with the servo motor 231; the driven sprocket 234 is arranged at both ends of the other side of the guide seat 11; the support wheel 235 is arranged between the driving sprocket 232 and the driven sprocket 234; the rotating column 236 is fixedly assembled inside the driven sprocket 234 and the support wheel 235 respectively, and the rotating column 236 is rotatably connected to the guide seat 11. The moving part 23 also includes a chain 237, a fixed plate 238, Guide block 239, guide groove 240 and pulley 241; chain 237 is sleeved on the outer surfaces of driving sprocket 232, driven sprocket 234 and support wheel 235, and chain 237 is engaged with driving sprocket 232, driven sprocket 234 and support wheel 235; fixed plate 238 is fixedly assembled with chain 237, and fixed block 24 is fixedly assembled at the bottom of fixed plate 238; guide block 239 is fixedly assembled at both ends inside guide seat 11; guide groove 240 is opened inside guide block 239; pulley 241 is arranged at both ends of the bottom of fixed plate 238, and pulley 241 is slidably connected inside guide groove 240.

[0112] In this embodiment, the guide seat 11 and the fixed column 12 are assembled into the body 1, the fixed column 12 is connected to the top of the tunnel, the gas detection unit 2 is installed inside the body 1, and the catalytic combustion sensor 21, the infrared gas sensor 22 and the processor are installed inside the protective shell 27 to form a detection component. The servo motor 231 is fixed to one side of the inside of the guide seat 11, and the driving sprocket 232, the driven sprocket 234, the support wheel 235 and the chain 237 are installed. The fixed plate 238 is fixed to the chain 237, and then the fixed block 24 is fixed to the bottom of the fixed plate 238. The vacuum pump 25, the suction pipe 26 and the solenoid valve are installed to complete the assembly of the device. The operating principle of the moving part 23 is as follows: the length of the corresponding guide seat 11 is spliced ​​according to the length of the tunnel, the length of the chain 237 is selected according to the length of the guide seat 11, and the servo motor 231 is started, and the servo motor 231 begins to operate. The servo motor 231 drives the connecting column 233 to rotate, thereby causing the driving sprocket 232 to start rotating. The rotation of the driving sprocket 232 is transmitted to the driven sprocket 234 and the support wheel 235 through the chain 237. Since the chain 237 is engaged with each sprocket and the support wheel 235, the entire transmission system starts working. The movement of the chain 237 drives the fixed plate 238 fixedly assembled with it to move. Since the driving sprockets 232, the driven sprockets 234 and the support wheels 235 at both ends are of the same size, the chains 237 at both ends can move synchronously, thereby ensuring that the fixed plate 238 will not be offset. During the detection process, according to different detection requirements and detection stages, the processor will adjust the speed of the servo motor 231 according to the preset drive control model, thereby changing the movement speed of the detection component. When the catalytic combustion sensor 21 is initially located in the approximate area of ​​​​gas leakage, the processor will reduce the speed of the servo motor 231, so that the detection component moves at a slower speed in this area, so that the infrared gas sensor 22 can measure the gas concentration more accurately. When the detection task is completed, that is, the processor accurately locates the gas leakage point according to the data of the infrared gas sensor 22 and triggers the alarm device, it sends a stop signal to the servo motor 231, the servo motor 231 stops running, and the drive component stops working.

[0113] Example 2:

[0114] The embodiment of the present invention discloses a tunnel construction gas detection device and its use method. Figure 1 、 4 , 5, 6, 7, including a body 1, the body 1 is assembled from a guide base 11 and a fixed column 12, the interior of the body 1 is provided with a gas detection unit 2, the gas detection unit 2 includes a detection member and a moving member 23;

[0115] The detection component is slidably arranged inside the guide seat 11, and the detection component includes a catalytic combustion sensor 21, an infrared gas sensor 22 and a processor;

[0116] The catalytic combustion sensor 21 and the infrared gas sensor 22 are activated in turn to detect gas. The catalytic combustion sensor 21 is used to locate the approximate area of ​​gas leakage, and the infrared gas sensor 22 is used to accurately measure the gas concentration and transmit the data to the processor. The processor accurately locates the leakage point according to the step-by-step change of gas concentration and triggers the alarm unit.

[0117] The moving member 23 is disposed inside the machine body 1 . The moving member 23 is drivingly connected to the detecting member. The moving member 23 is used to drive the detecting member to perform a reciprocating motion inside the guide seat 11 .

[0118] The outer surface of the catalytic combustion sensor 21 and the infrared gas sensor 22 is provided with a protective shell 27, and the interior of the protective shell 27 is provided with an insulation block 28. The insulation block 28 is used to separate the catalytic combustion sensor 21 and the infrared gas sensor 22. A fixed block 24 is provided on one side of the protective shell 27, and an air pump 25 is provided inside the fixed block 24. The top of the air pump 25 is connected with an intake pipe 26, and the intake pipe 26 is respectively connected to the catalytic combustion sensor 21 and the infrared gas sensor 22. An electromagnetic valve is provided at the connection between the intake pipe 26 and the catalytic combustion sensor 21 and the infrared gas sensor 22. The electromagnetic valve is used to control the air pump 25 to exhaust a certain sensor. The interior of the catalytic combustion sensor 21 is provided with a first air chamber 211, and the bottom of the catalytic combustion sensor 21 is provided with a first air chamber 212. A filter 212, a breathable plate 213 is provided above the first filter 212, the breathable plate 213 is fixedly assembled to the inner wall of the first air chamber 211, a wire post 214 is fixedly assembled below the breathable plate 213, the wire post 214 is symmetrically arranged, a ceramic post 215 is provided below the breathable plate 213, a wire 216 is wound around the outer surface of the wire post 214 and the ceramic post 215, and the wire post 214 and the ceramic post 215 are electrically connected through the wire 216, a second air chamber 221 is provided inside the infrared gas sensor 22, an air inlet 222 is provided on one side of the infrared gas sensor 22, a second filter 223 is fixedly assembled inside the air inlet 222, a light-emitting component 224 is provided at the lower end of the second air chamber 221, and a receiving component 225 is provided at the upper end of the second air chamber 221.

[0119] In this embodiment, the detection element operates as follows: at the start of detection, the catalytic combustion sensor 21 is first activated. An air pump 25 extracts gas from the tunnel through an air intake pipe 26, and a solenoid valve controls the entry of the gas into the catalytic combustion sensor 21. After the gas passes through a first filter 212 to remove dust and other impurities, it enters the first air chamber 211. Within the first air chamber 211, the gas comes into contact with a wire 216 below the air permeable plate 213. The catalyst on the wire 216 causes the combustible gas to undergo a combustion reaction. The presence of the combustible gas is detected based on changes in the heat generated by the combustion. The catalytic combustion sensor 21 transmits the detected gas data to a processor, which analyzes the data in real time. When the combustible gas concentration is detected to exceed a set threshold, a gas leak is determined to exist, and the approximate area of ​​the gas leak is preliminarily located based on the position information of the sensor within the guide seat 11. Once the catalytic combustion sensor 21 locates the approximate area of ​​the gas leak, the processor controls the solenoid valve to stop pumping gas to the catalytic combustion sensor 21 and prepares to switch to the infrared gas sensor 22 for more accurate detection. The processor controls the solenoid valve to open the channel between the intake pipe 26 and the infrared gas sensor 22, and the air pump 25 draws the gas into the second air chamber 221 through the air inlet 222 and the second filter 223. Within the second air chamber 221, the light-emitting element 224 emits infrared light of a specific wavelength. When specific components in the gas absorb the infrared light, the intensity of the infrared light received by the receiving element 225 changes. The gas concentration is accurately measured based on this change, and the infrared gas sensor 22 transmits the accurately measured gas concentration data to the processor in real time. Simultaneously, the detector, driven by a driver, moves slowly across the leak area, continuously collecting gas concentration data at different locations. The processor, based on the received data on the gradual changes in gas concentration, uses a pre-set calculation model to precisely locate the leak. Once the leak is located, the processor triggers the alarm unit to sound an alarm, prompting construction personnel to take appropriate measures.

[0120] Example 3:

[0121] The embodiment of the present invention discloses a tunnel construction gas detection device and its use method. Figure 1 、 8 9, comprising a body 1, the body 1 is assembled from a guide base 11 and a fixed column 12, a gas detection unit 2 is provided inside the body 1, and the gas detection unit 2 includes a detection member and a moving member 23;

[0122] The detection component is slidably arranged inside the guide seat 11, and the detection component includes a catalytic combustion sensor 21, an infrared gas sensor 22 and a processor;

[0123] The catalytic combustion sensor 21 and the infrared gas sensor 22 are activated in turn to detect gas. The catalytic combustion sensor 21 is used to locate the approximate area of ​​gas leakage, and the infrared gas sensor 22 is used to accurately measure the gas concentration and transmit the data to the processor. The processor accurately locates the leakage point according to the step-by-step change of gas concentration and triggers the alarm unit.

[0124] The moving member 23 is disposed inside the machine body 1 . The moving member 23 is drivingly connected to the detecting member. The moving member 23 is used to drive the detecting member to perform a reciprocating motion inside the guide seat 11 .

[0125] The computational model of the processor is as follows;

[0126] 1. Drive control model

[0127] Assume the tunnel length is L, the driving member motion speed function is:

[0128]

[0129]

[0130] Position function:

[0131]

[0132] Indicates that time t is in a specific detection stage;

[0133] V(t) is the velocity as a function of time;

[0134] V(0): speed in the initial detection phase;

[0135] V(1): speed of the precise detection stage;

[0136] dt is the differential symbol in calculus, representing an infinitesimal increment of time;

[0137] The position function x(t) is obtained by integrating the velocity function:

[0138]

[0139] dt: integral variable, representing a small change in time t;

[0140] dt is used in the integration to accumulate the change of acceleration over time, and finally obtain the position x(t) of the driving member.

[0141] 2. Dual Sensor Fusion Detection Model

[0142] 1. Rough detection stage (catalytic combustion type):

[0143]

[0144] 2. Precision detection stage (infrared sensor):

[0145]

[0146] G(x): output signal of the sensor at position x

[0147] K1: reflects the response intensity of the sensor to combustible gas and is related to the efficiency of the catalytic combustion reaction;

[0148] a: describes the exponential decay characteristics of gas concentration as it spreads from the leak point, which is related to the tunnel ventilation conditions;

[0149] ε1 ~ N(0, σ1²): measurement noise with mean 0 and variance Normal distribution;

[0150] H(x): output signal of the sensor at position x

[0151] K2: related to the infrared absorption cross section of gas molecules, which determines the selectivity of the sensor to specific gases;

[0152] : nonlinear saturation coefficient;

[0153] ε2 ~ N(0, σ2²): measurement noise, with mean 0 and variance Normal distribution;

[0154] 3. Leakage Area Location Algorithm

[0155] Based on the gradient ascent method:

[0156]

[0157] Define suspicious areas:

[0158] : The position corresponding to the maximum value of the catalytic combustion detector signal gradient;

[0159] : half width of the suspicious area;

[0160] Physical meaning;

[0161]

[0162]

[0163] 4. Concentration Field Reconstruction Model

[0164] Use Gaussian kernel density estimation:

[0165]

[0166] The concentration field was reconstructed by Gaussian kernel density estimation;

[0167] h: kernel function bandwidth

[0168] Controlling the smoothness of the concentration field requires satisfying the sampling theorem

[0169] Gaussian kernel function:

[0170] Function: Discrete infrared sensor measurement value Smooth interpolation to a continuous concentration field.

[0171] 5. Accurately locate the leakage point

[0172] Solve for the maximum concentration gradient:

[0173]

[0174] Leakage point:

[0175] Reconstructing the spatial gradient of the concentration field

[0176] Calculation method:

[0177]

[0178]

[0179] 6. Alarm triggering conditions

[0180] When satisfied:

[0181]

[0182] The alarm system is triggered

[0183] Model parameter optimization:

[0184]

[0185] C_threshold = 5%LEL: combustible gas concentration alarm threshold;

[0186] ∇C_threshold = 2%(LEL / m): Concentration gradient alarm threshold.

[0187] Step 1: Start the catalytic combustion sensor 21, drive it to move back and forth inside the guide seat 11 through the moving part 23, and detect the combustible gas in real time; Step 2: The catalytic combustion sensor 21 detects the combustible gas leakage and locates the approximate area of ​​the gas leakage; Step 3: Switch to the infrared gas sensor 22, and reduce the speed of the moving part 23 in the gas leakage area. At the same time, the infrared gas sensor 22 continues to detect the concentration of the leaked gas and transmits the real-time data to the inside of the processor; Step 4: The processor accurately locates the leakage point according to the change in the gas leakage concentration and triggers the alarm device.

[0188] In this embodiment, if no gas leaks occur during the detection process of the catalytic combustion sensor 21, the movable member 23 drives the catalytic combustion sensor 21 to continue detection. Once it is found that the combustible gas in the air exceeds the preset alarm value, the movable member 23 reduces the detection speed and locates the approximate area. The device switches to the infrared gas sensor 22 for more accurate detection. The infrared gas sensor 22 collects gas concentration data at different locations and transmits the data in real time to the processor. The processor uses a preset calculation model based on the received gas concentration step change data to accurately locate the gas leak point. Once the leak point is determined, the processor triggers the alarm unit to sound an alarm, reminding the construction personnel to take appropriate measures to meet the user's needs.

[0189] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A tunnel construction gas detection device, comprising a body (1), wherein the body (1) is assembled from a guide seat (11) and a fixed column (12), characterized in that: A gas detection unit (2) is provided inside the body (1), and the gas detection unit (2) comprises: A detection member is slidably disposed inside the guide seat (11), the detection member comprising a catalytic combustion sensor (21), an infrared gas sensor (22) and a processor; The catalytic combustion sensor (21) and the infrared gas sensor (22) are activated in turn to detect gas. The catalytic combustion sensor (21) is used to locate the approximate area of ​​gas leakage, and the infrared gas sensor (22) is used to accurately measure gas concentration and transmit the data to the processor. The processor accurately locates the leakage point according to the step-by-step change of gas concentration and triggers the alarm unit. A moving member (23) is arranged inside the machine body (1), and the moving member (23) is drivingly connected to the detection member. The moving member (23) is used to drive the detection member to move back and forth inside the guide seat (11).

2. A tunnel construction gas detection device according to claim 1, characterized in that: The outer surfaces of the catalytic combustion sensor (21) and the infrared gas sensor (22) are provided with a protective shell (27), and the interior of the protective shell (27) is provided with a heat insulation block (28), and the heat insulation block (28) is used to separate the catalytic combustion sensor (21) and the infrared gas sensor (22).

3. A tunnel construction gas detection device according to claim 2, characterized in that: A fixing block (24) is provided on one side of the protective shell (27), an air pump (25) is provided inside the fixing block (24), the top of the air pump (25) is connected to an air intake pipe (26), the air intake pipe (26) is respectively connected to the catalytic combustion sensor (21) and the infrared gas sensor (22), and an electromagnetic valve is provided at the connection between the air intake pipe (26) and the catalytic combustion sensor (21) and the infrared gas sensor (22), and the electromagnetic valve is used to control the air pump (25) to exhaust air from a certain sensor.

4. The tunnel construction gas detection device according to claim 1, characterized in that: A first air chamber (211) is provided inside the catalytic combustion sensor (21), a first filter (212) is provided at the bottom of the catalytic combustion sensor (21), an air permeable plate (213) is provided above the first filter (212), and the air permeable plate (213) is fixedly assembled with the inner wall of the first air chamber (211).

5. A tunnel construction gas detection device according to claim 4, characterized in that: A wire post (214) is fixedly mounted below the air permeable plate (213), and the wire posts (214) are symmetrically arranged. A ceramic post (215) is arranged below the air permeable plate (213), and a wire (216) is wound around the outer surfaces of the wire post (214) and the ceramic post (215). The wire post (214) and the ceramic post (215) are electrically connected via the wire (216).

6. The tunnel construction gas detection device according to claim 1, characterized in that: A second air chamber (221) is provided inside the infrared gas sensor (22), an air inlet (222) is provided on one side of the infrared gas sensor (22), a second filter (223) is fixedly mounted inside the air inlet (222), a light emitting component (224) is provided at the lower end of the second air chamber (221), and a receiving component (225) is provided at the upper end of the second air chamber (221).

7. The tunnel construction gas detection device according to claim 1, characterized in that: The moving member (23) includes: A servo motor (231) is fixedly mounted on one side of the guide seat (11); A driving sprocket (232) is provided at both ends of the guide seat (11); A connecting column (233) is fixedly assembled inside the driving sprocket (232), and the connecting column (233) is fixedly assembled with the servo motor (231); A driven sprocket (234) is provided at both ends of the other side of the guide seat (11); a supporting wheel (235) disposed between the driving sprocket (232) and the driven sprocket (234); The rotating column (236) is fixedly assembled inside the driven sprocket (234) and the supporting wheel (235), and the rotating column (236) is rotatably connected to the guide seat (11).

8. The tunnel construction gas detection device according to claim 7, characterized in that: The moving member (23) further comprises: a chain (237) sleeved on the outer surfaces of the driving sprocket (232), the driven sprocket (234) and the support wheel (235), wherein the chain (237) is meshed with the driving sprocket (232), the driven sprocket (234) and the support wheel (235); A fixed plate (238) is fixedly assembled with the chain (237), and the detection member is fixedly assembled at the bottom of the fixed plate (238); Guide blocks (239) are fixedly mounted at both ends of the guide seat (11); A guide groove (240) is provided inside the guide block (239); Pulleys (241) are provided at both ends of the bottom of the fixing plate (238), and the pulleys (241) are slidably connected to the inside of the guide groove (240).

9. The tunnel construction gas detection device according to claim 1, characterized in that: The computing model of the processor is as follows; 1. Drive control model Assume the tunnel length is L, the driving member motion speed function is: v(t)={v0, when t∈preliminary detection stage; v 1， When t∈precision detection stage}(v1 <v0) Position function: x(t) = ∫v(t)dt t∈The symbol∈ means "belongs to" Indicates that time t is in a specific detection stage; V(t) is the velocity as a function of time; V(0): velocity during the initial detection phase; V(1): speed of the precise detection stage; dt is the differential symbol in calculus, representing an infinitesimal increment of time; The position function x(t) is obtained by integrating the velocity function: dt: integral variable, representing a small change in time t; dt is used in the integration to accumulate the change of acceleration over time, and finally obtain the position x(t) of the driving part.

1. Rough detection stage (catalytic combustion type): G(x)=k1.C(x).e^(-ax)+ε1(k1 is the sensitivity coefficient, ε1~N(0,σ1 2 )) 2. Precision detection stage (infrared sensor): H(x)=k2.C(x) / (1+β.C(x))+ε2(ε2~N(0,σ2 2 ),σ2 2 <σ1 2 ) G(x): output signal of the sensor at position x K1: reflects the response intensity of the sensor to combustible gas and is related to the efficiency of the catalytic combustion reaction; a: describes the exponential decay characteristics of gas concentration as it spreads from the leak point, which is related to the tunnel ventilation conditions; ε1~N(0,σ1 2 ): measurement noise, with mean 0 and variance Normal distribution; H(x): output signal of the sensor at position x K2: related to the infrared absorption cross section of gas molecules, which determines the selectivity of the sensor to specific gases; β: nonlinear saturation coefficient; ε2~N(0,σ2 2 ): measurement noise, with mean 0 and variance Normal distribution; 3. Leakage Area Location Algorithm Based on the gradient ascent method: Define suspicious areas: The position corresponding to the maximum value of the catalytic combustion detector signal gradient; Δx=3σ x : half width of the suspicious area; Physical meaning; σ x yes Positioning uncertainty (standard deviation) is determined by sensor noise and velocity error. 3σ is selected. x Indicates the suspicious area Ω is delineated with a 99.7% confidence interval (3σ principle) 4. Concentration Field Reconstruction Model Use Gaussian kernel density estimation: The concentration field was reconstructed by Gaussian kernel density estimation; h: kernel function bandwidth Control the smoothness of the concentration field, which must satisfy the sampling theorem h<0.5 v1 .t sample (e.g. h = 0.2m) Gaussian kernel function: Function: To convert the discrete infrared sensor measurement value H(x i ) is smoothly interpolated into a continuous concentration field.

5. Accurately locate the leak point Solve for the maximum concentration gradient: Leak point: Reconstructing the spatial gradient of the concentration field Calculation method: The severity of the change in reaction concentration. x * : Exact location of the leak Determination method: That is, the point where the absolute value of the gradient is the largest is the leakage source.

6. Alarm triggering conditions When satisfied: Make and The alarm system is triggered Model parameter optimization:

1. Speed ​​parameters: v0 = 1.5 m / s, v1 = 0.3 m / s (based on sensor response time) 2. Core bandwidth: h = 0.2m (satisfies Nyquist sampling theorem) 3.Threshold setting: C_threshold=5%LEL, C_threshold=5%LEL: combustible gas concentration alarm threshold; Concentration gradient alarm threshold.

10. A method for using a tunnel construction gas detection device, the tunnel construction gas detection device according to claim 1-9, characterized in that: The following steps are included: Step 1: Start the catalytic combustion sensor (21), drive it to move back and forth inside the guide seat (11) through the moving part (23), and detect the combustible gas in real time; Step 2: The catalytic combustion sensor (21) detects the leakage of combustible gas and locates the approximate area of ​​the gas leakage; Step 3: Switch to the infrared gas sensor (22), and when the moving part (23) reduces its speed in the gas leakage area, the infrared gas sensor (22) continues to detect the concentration of the leaked gas and transmits the real-time data to the inside of the processor; Step 4: The processor accurately locates the leakage point according to the change in gas leakage concentration and triggers the alarm device.

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