A gas detection device and method in a shield tunnel

Abstract

The present invention belongs to the technical field of gas detection, and specifically relates to a gas detection device and method in a shield tunnel, including a detection platform. Installation platforms are fixedly connected to both side walls of the detection platform. Installation holes are formed on the surface of each installation platform, and external embedded screw rods can be fixedly embedded in the bottom or top of the tunnel through the installation holes. A gas detection seat is arranged above the detection platform. Symmetrically arranged air extraction pipes are installed on the lower end surface of the gas detection seat. An air extraction fan is rotatably arranged inside each air extraction pipe. The air extraction fan is connected to the output end of an external micro motor. The air extraction fan is used to quickly draw harmful gases with a specific gravity greater than that of air into the air extraction pipe. The micro motor drives the air extraction fan inside the air extraction pipe to rotate, so that the air extraction fan draws the harmful gases deposited near the tunnel ground into the air extraction pipe, and the gas detection seat detects and processes the toxic gases.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas detection, and specifically relates to a gas detection device and method in a shield tunnel. Background Art

[0002] The basic working principle of a shield machine is to excavate the soil while advancing forward along the tunnel axis. The cylindrical component of the shield machine, i.e., the shield, plays a role of temporarily supporting the unlined tunnel section excavated. Combustible gases and toxic and harmful gases are likely to be generated during tunnel construction, and these gases remain in the tunnel, posing a threat to the health and life safety of construction workers and may also cause significant losses to the project.

[0003] Some existing technologies have also proposed some solutions for tunnel gas detection. For example, a Chinese patent application with the publication number CN117248902A discloses an advanced detection device for harmful tunnel gases during drilling, including legs, a bracket, a water and gas separation box, a direction adjustment component, a drilling component, a gas detection component, and an internal auxiliary component. The water and gas separation box is fixedly arranged on the legs, the gas detection component is fixedly arranged on the water and gas separation box, the gas detection component is communicated with the water and gas separation box, and the internal auxiliary component is arranged inside the water and gas separation box. This invention belongs to the technical field of tunnel construction, specifically referring to an advanced detection device for harmful tunnel gases during drilling; it solves the problem that the existing advanced detection device for harmful tunnel gases during drilling on the market cannot automatically adjust the drill rod angle according to the deflection size of the drill rod.

[0004] Although the above technical solution solves the problem that the advanced detection device cannot automatically adjust the drill rod angle according to the deflection size of the drill rod, there are still other problems in actual use. For example, there are many types of gases during the construction of a shield tunnel, and these toxic gases include carbon monoxide, methane, hydrogen sulfide, sulfur dioxide, and dust particles, etc.

[0005] Some of these toxic gases have a specific gravity greater than that of air, and some have a specific gravity less than that of air. For example, harmful gases such as hydrogen sulfide are heavier than air, and these toxic gases with a specific gravity greater than that of air will deposit near the tunnel floor, making it more troublesome to detect these gases.

[0006] Therefore, the present invention provides a gas detection device and method in a shield tunnel. Summary of the Invention

[0007] In order to make up for the deficiencies of the existing technology and solve at least one technical problem proposed in the background art.

[0008] The technical solution adopted by the present invention to solve its technical problems is as follows: A gas detection device in a shield tunnel described in the present invention includes a detection platform. Installation platforms are fixedly connected to both side walls of the detection platform. Installation holes are formed on the surface of each installation platform. Through the installation holes, externally connected embedding screws can be fixedly embedded at the bottom or top of the tunnel. A gas detection seat is arranged above the detection platform. Symmetrically arranged air extraction pipes are installed on the lower end surface of the gas detection seat. An air extraction fan is rotatably arranged inside each air extraction pipe. The air extraction fan is connected to the output end of an externally connected micro motor. The air extraction fan is used to quickly extract harmful gases with a specific gravity greater than that of air into the air extraction pipe, so that the harmful gases can be detected in the first time.

[0009] Preferably, an L-shaped support rod is fixedly installed inside each air extraction pipe. The air extraction fan is rotatably arranged at the end of the L-shaped support rod. A circular filter plate is installed inside the air extraction pipe and on the side of the air extraction fan. The circular filter plate is used to block large dust particles in the tunnel.

[0010] Preferably, a reciprocating lead screw is installed on the side of the air extraction fan away from the L-shaped support rod. A cleaning unit is arranged on the outer peripheral surface of the reciprocating lead screw. The cleaning unit is used to clean the inner wall of the air extraction pipe. The shape of the air extraction pipe is large in diameter at one end and small in diameter at the other end. The air extraction fan is arranged at the connection of the large diameter and small diameter of the air extraction pipe.

[0011] Preferably, the cleaning unit includes a slider threadedly arranged on the reciprocating lead screw. Four support rods are fixedly installed on the outer peripheral surface of the slider. Cleaning rings are fixedly installed at the ends of the four support rods. A cleaning sponge is sleeved on the outer surface of the cleaning ring. The cleaning part of the cleaning ring contacts the inner wall of the air extraction pipe. Two fixed shafts are installed on the inner wall of the cleaning ring. A cleaning shaft is rotatably arranged on the outer wall of the fixed shaft. A cleaning sponge is sleeved on the outside of the cleaning shaft.

[0012] Preferably, the cleaning unit further includes a fixed ring fixedly installed at the end of the support rod away from the slider. A plurality of elastic rods arranged in a circumferential array are fixedly installed on the outer wall of the fixed ring. A telescopic spring is sleeved on the outer peripheral surface of each elastic rod. The cleaning ring is fixedly installed at the end of one group of the elastic rods. A fillet is arranged on the outer wall of the cleaning ring. The reciprocating lead screw extends out of the outside of the air extraction pipe.

[0013] Preferably, a rectangular groove is formed above the detection platform. A fixed block is slidably arranged on the groove wall of the rectangular groove. The air extraction pipe is connected to the side wall of the fixed block through a connection unit. A reciprocating cylinder is fixedly installed at the edge of the detection platform. The telescopic end of the reciprocating cylinder is connected to the side wall of the fixed block. A roller is arranged at the contact position between the fixed block and the rectangular groove.

[0014] Preferably, the connecting unit includes a limiting frame slidably disposed on the side wall of the fixed block. There are two limiting frames, which are symmetrically arranged with respect to the fixed block. An annular clamping plate is fixedly installed on the side wall of each limiting frame, and the annular clamping plate is connected to the outer wall of the air extraction pipe.

[0015] Preferably, limiting grooves are formed on both side walls of the fixed block. The limiting frame is slidably disposed inside the limiting groove. An arc-shaped pressing plate I is fixedly connected to the bottom of the limiting frame. A plurality of arc-shaped pressing plates II are installed on the side wall of the detection platform. During the movement of the fixed block, the limiting frame and the arc-shaped pressing plate I on its side wall will be driven to move, and the arc-shaped end of the arc-shaped pressing plate I will contact the arc-shaped end of the arc-shaped pressing plate II.

[0016] Preferably, an elastic telescopic column is installed at the bottom of the limiting frame. A spring is sleeved on the outer surface of the elastic telescopic column. The bottom of the elastic telescopic column is connected to the end face of the bracket extended by the fixed block; during operation, when the limiting frame moves upward, the limiting frame will simultaneously pull the elastic telescopic column at its bottom. When the arc-shaped pressing plate I and the arc-shaped pressing plate II are separated, under the elastic force of the elastic telescopic column, the limiting frame will return to its initial position. Since there are multiple arc-shaped pressing plates II, when the arc-shaped pressing plates II at different positions contact the arc-shaped pressing plate I, the detection rate of the tunnel gas is greatly improved, which is beneficial to the excavation of the tunnel.

[0017] Preferably, a gas detection method in a shield tunnel, this detection method adopts the above-mentioned gas detection device in a shield tunnel, including the following steps:

[0018] S1. Place the detection platform at a suitable position in the tunnel, and fixedly install it in the installation hole through an externally connected embedded screw, and fixedly install this detection platform at a suitable place in the tunnel;

[0019] S2. Control the externally connected controller to make the micro motor drive the air extraction fan inside the air extraction pipe to rotate, so that the air extraction fan sucks the harmful gas deposited near the tunnel ground into the air extraction pipe, and the gas detection seat detects and processes the toxic gas, so that the toxic gas deposited on the ground can be quickly sucked into the gas detection seat.

[0020] Preferably, the gas detection seat in step S2 includes a display and an alarm.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. An apparatus and method for gas detection in a shield tunnel according to the present invention suck harmful gases deposited near the tunnel floor into the inside of a suction pipe through a suction fan, and detect and process the toxic gases through a gas detection seat. With such a design, the toxic gases deposited on the ground can be quickly sucked into the gas detection seat, enabling the harmful gases to be detected immediately when leakage occurs, reducing the possibility of harmful gases entering the air with the wind and endangering the health of the staff, and improving the beneficial effects of subsequent excavation of the shield tunnel.

[0023] 2. An apparatus and method for gas detection in a shield tunnel according to the present invention, the slider will slowly drive the cleaning ring to disengage from the suction pipe. When the cleaning ring disengages from the suction pipe, the elastic rod in the compressed state will recover, driving the cleaning ring to vibrate by a certain amplitude, causing the dust and impurities adhered to the cleaning ring to shake off and fall outside the tunnel. When the reciprocating lead screw drives the slider to move again towards the inside of the suction pipe, since the outer wall of the cleaning ring is provided with a rounded corner, it can quickly enter the inside of the suction pipe, and the elastic rod is again in a compressed state, thus facilitating the subsequent cleaning of the inner wall of the suction pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] Figure 1 is a perspective view of the present invention;

[0026] Figure 2 is a partial structural schematic diagram of the suction pipe in the present invention;

[0027] Figure 3 is a partial structural schematic diagram of the fixing block in the present invention;

[0028] Figure 4 is a cross-sectional structural schematic diagram of the suction pipe in the present invention;

[0029] Figure 5 is a structural schematic diagram of the reciprocating lead screw in the present invention;

[0030] Figure 6 is a partial structural schematic diagram of the cleaning ring in the present invention;

[0031] Figure 7 is a structural schematic diagram of the cleaning shaft in the present invention;

[0032] Figure 8 is a side view structural schematic diagram of the present invention;

[0033] Figure 9 is a partial structural schematic diagram of the limiting frame in the present invention;

[0034] Figure 10 is a partial structural schematic diagram of the first arc-shaped pressing plate and the second arc-shaped pressing plate in the present invention;

[0035] Figure 11 This is the flowchart of the method in the present invention.

[0036] In the figure: 1. Detection platform; 2. Installation table; 201. Installation hole; 3. Gas detection seat; 4. Exhaust pipe; 401. L-shaped support rod; 5. Exhaust fan; 6. Circular filter plate; 7. Reciprocating lead screw; 8. Slide block; 9. Support rod; 10. Cleaning ring; 11. Fixed ring; 12. Elastic rod; 13. Rectangular groove; 14. Fixed block; 15. Reciprocating cylinder; 16. Limit frame; 161. Ring-shaped clamping plate; 17. Limit groove; 18. Arc-shaped pressing plate I; 19. Arc-shaped pressing plate II; 20. Elastic telescopic column. Detailed implementation manners

[0037] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific implementation manners.

[0038] As Figures 1 to 4 shown, a gas detection device in a shield tunnel according to an embodiment of the present invention includes a detection platform 1. Both side walls of the detection platform 1 are fixedly connected with installation tables 2. Each installation table 2 is provided with an installation hole 201 on its surface. An external embedded screw can be fixedly embedded in the bottom or top of the tunnel through the installation hole 201. A gas detection seat 3 is arranged above the detection platform 1. Symmetrically arranged exhaust pipes 4 are installed on the lower end surface of the gas detection seat 3. Each exhaust pipe 4 is rotatably provided with an exhaust fan 5 inside. The exhaust fan 5 is connected to the output end of an external micro motor. The exhaust fan 5 is used to quickly draw harmful gases with a specific gravity greater than that of air into the exhaust pipe 4, so that the harmful gases can be detected in the first time;

[0039] During operation, combustible gases and toxic and harmful gases will be generated during the construction of the shield tunnel. Some of these toxic gases have a specific gravity greater than that of air, and some have a specific gravity less than that of air. These toxic gases with a specific gravity greater than that of air will deposit near the tunnel floor, making it more troublesome to detect these gases. Therefore, this gas detection device can be used for detection;

[0040] First, install the gas detection device of the present invention. Place the detection platform 1 at a suitable position in the tunnel, and fix it in the embedding installation hole 201 through an externally connected embedding screw, and fixedly install the detection platform 1 at a suitable place in the tunnel. Then, control the external controller to make the miniature motor drive the air extraction fan 5 inside the air extraction pipe 4 to rotate, so that the air extraction fan 5 sucks the harmful gas deposited near the tunnel floor into the air extraction pipe 4, and the gas detection seat 3 detects and processes the toxic gas. The method of the gas detection seat 3 detecting the gas in the tunnel is the prior art and will not be elaborated in the embodiments of the present invention. With such a design, the toxic gas deposited on the ground can be quickly sucked into the gas detection seat 3, so that the harmful gas can be detected immediately when it leaks, reducing the possibility of the harmful gas entering the air with the wind and endangering the health of the staff, and improving the beneficial effect of the subsequent excavation of the shield tunnel;

[0041] It should be noted that the suitable positions of the tunnel mentioned in the present invention are dangerous places where gas is likely to leak, such as the tunnel entrance, the middle of the tunnel, the tunnel bifurcation, and the blasting area;

[0042] It should also be noted that the gas detection device can also install the installation platform 2 and the detection platform 1 on the top of the tunnel through an externally connected embedding screw, so that the gas detection seat 3 can also detect the toxic gas with a specific gravity less than that of air, improving the practicability of the present invention.

[0043] As Figures 2 to 8 shown, an L-shaped support rod 401 is fixedly installed inside each air extraction pipe 4, the air extraction fan 5 is rotatably arranged at the end of the L-shaped support rod 401, and a circular filter plate 6 is installed inside the air extraction pipe 4 and on the side of the air extraction fan 5. The circular filter plate 6 is used to block large dust particles in the tunnel; during operation, after the detection platform 1 is installed and the air extraction pipe 4 intakes air, the circular filter plate 6 designed inside the air extraction pipe 4 can block some larger dust particles, preventing the dust particles from entering the gas detection seat 3 along the air extraction pipe 4 and affecting the use of the gas detection seat 3, and also avoiding the problem that larger dust particles touch the air extraction fan 5 and damage the air extraction fan 5.

[0044] A reciprocating screw rod 7 is installed on the side of the air extraction fan 5 away from the L-shaped support rod 401. A cleaning unit is arranged on the outer peripheral surface of the reciprocating screw rod 7. The cleaning unit is used to clean the inner wall of the air extraction pipe 4. The shape of the air extraction pipe 4 is large in diameter at one end and small in diameter at the other end. The air extraction fan 5 is arranged at the connection of the large diameter and the small diameter in the air extraction pipe 4;

[0045] During operation, when the exhaust fan 5 is operating normally, the exhaust fan 5 will drive the reciprocating screw rod 7 at its end to rotate simultaneously. The reciprocating screw rod 7 will drive the cleaning unit connected to it to operate. The cleaning unit can not only sweep away the dust particles blocked at the front end of the exhaust pipe 4, that is, in front of the circular filter plate 6, but also dehumidify the front end of the exhaust pipe 4 to avoid the problem that excessive moisture affects the normal detection of the gas detection seat 3.

[0046] The cleaning unit includes a slider 8 threadedly arranged on the reciprocating screw rod 7. Four support rods 9 are fixedly installed on the outer peripheral surface of the slider 8. Cleaning rings 10 are fixedly installed at the ends of the four support rods 9. The cleaning parts of the cleaning rings 10 are in contact with the inner wall of the exhaust pipe 4. During operation, when the reciprocating screw rod 7 rotates, the reciprocating screw rod 7 will drive the slider 8 threadedly connected to it to move simultaneously. The slider 8 will drive the four support rods 9 connected to it to move. The four support rods 9 drive the cleaning rings 10 to move synchronously, so that the cleaning rings 10 move outward along the inner wall of the exhaust pipe 4. Then the cleaning rings 10 will sweep away the dust particles blocked in front of the circular filter plate 6 to avoid the problem that too many particles affect the air extraction effect of the exhaust pipe 4 and improve the detection effect of harmful gases.

[0047] Two fixed shafts 101 are installed on the inner wall of the cleaning ring 10. A cleaning shaft 102 is rotatably arranged on the outer wall of the fixed shaft 101. A cleaning sponge is sleeved outside the cleaning shaft 102.

[0048] It should be noted that as shown in the attached Figure 7 When the cleaning ring 10 moves along the inner wall of the exhaust pipe 4 and cleans the inner wall of the exhaust pipe 4, at this time, the cleaning shaft 102 and the cleaning sponge on its outer surface are in contact with the inner wall of the exhaust pipe 4. And when the cleaning shaft 102 moves in contact with the inner wall of the exhaust pipe 4, the cleaning shaft 102 itself will rotate at a certain angle, so as to improve the cleaning effect of the particles on the inner wall of the exhaust pipe 4, and can adsorb the water droplets condensed on the inner wall of the exhaust pipe 4 to avoid the problem that the water droplets condensed on the inner wall of the exhaust pipe 4 flow along its inner wall to the side of the gas detection seat 3, resulting in problems with the normal use of the gas detection seat 3.

[0049] As Figures 4 to 9As shown, the cleaning unit further includes a fixing ring 11 fixedly installed at the end of the support rod 9 away from the slider 8. A plurality of elastic rods 12 arranged in a circumferential array are fixedly installed on the outer wall of the fixing ring 11. A telescopic spring is sleeved on the outer peripheral surface of each elastic rod 12. The cleaning ring 10 is fixedly installed at the end of one group of the elastic rods 12. The outer wall of the cleaning ring 10 is provided with a rounded corner. The reciprocating lead screw 7 extends out of the outer side of the air extraction pipe 4. During operation, when the cleaning ring 10 moves on the inner wall of the air extraction pipe 4, all the elastic rods 12 connected to the cleaning ring 10 will be in a compressed state. When the slider 8 moves forward under the rotation of the reciprocating lead screw 7, and since the reciprocating lead screw 7 extends out of the outer side of the air extraction pipe 4, the slider 8 will slowly drive the cleaning ring 10 to separate from the air extraction pipe 4. When the cleaning ring 10 separates from the air extraction pipe 4, the elastic rods 12 in the compressed state will recover, driving the cleaning ring 10 to vibrate by a certain amplitude, so that the dust and impurities adhered to the cleaning ring 10 will fall off and drop outside the tunnel. When the reciprocating lead screw 7 drives the slider 8 to move again towards the inside of the air extraction pipe 4, due to the rounded corner provided on the outer wall of the cleaning ring 10, it can enter the inside of the air extraction pipe 4 as soon as possible, and the elastic rods 12 will be in a compressed state again, which is convenient for subsequent continuous cleaning of the inner wall of the air extraction pipe 4.

[0050] Specifically, when the air flow velocity in the tunnel is low, it may cause a decrease in the mixing and diffusion efficiency of harmful gases in the tunnel and a decrease in the detection efficiency. Therefore, the present invention further proposes the following embodiments; a rectangular groove 13 is opened above the detection platform 1. A fixing block 14 is slidably arranged on the groove wall of the rectangular groove 13. The air extraction pipe 4 is connected to the side wall of the fixing block 14 through a connecting unit. A reciprocating cylinder 15 is fixedly installed at the edge of the detection platform 1. The telescopic end of the reciprocating cylinder 15 is connected to the side wall of the fixing block 14. A roller is arranged at the contact position between the fixing block 14 and the rectangular groove 13.

[0051] During specific operation, after the detection platform 1 is installed inside the tunnel, the telescopic end of the reciprocating cylinder 15 can be controlled to move, so that the telescopic end of the reciprocating cylinder 15 drives the fixing block 14, the air extraction pipe 4 and the gas detection seat 3 to move synchronously, changing the air extraction position of the air extraction pipe 4 and increasing the air extraction range of the air extraction pipe 4, thus solving the problem that some toxic gases deposited on the ground are difficult to be detected when the gas flow velocity is low.

[0052] The connecting unit includes a limiting frame 16 slidably arranged on the side wall of the fixed block 14. There are two limiting frames 16, which are symmetrically arranged relative to the fixed block 14. An annular clamping plate 161 is fixedly installed on the side wall of each limiting frame 16, and the annular clamping plate 161 is connected to the outer wall of the air extraction pipe 4. During operation, when the fixed block 14 moves inside the rectangular groove 13, the fixed block 14 will drive the two side limiting frames 16, the annular clamping plates 161 and the air extraction pipe 4 to move simultaneously, and the air extraction pipe 4 drives the gas detection seat 3 to move synchronously, thus improving the detection speed of the gas in the tunnel.

[0053] As Figures 6 to 9 As shown in the figure, limiting grooves 17 are formed on both side walls of the fixed block 14. The limiting frame 16 is slidably arranged inside the limiting grooves 17. An arc-shaped pressing plate one 18 is fixedly connected to the bottom of the limiting frame 16. A plurality of arc-shaped pressing plates two 19 are installed on the side wall of the detection platform 1. During the movement of the fixed block 14, it will drive the limiting frame 16 and the arc-shaped pressing plate one 18 on its side wall to move, and the arc-shaped end of the arc-shaped pressing plate one 18 will contact the arc-shaped end of the arc-shaped pressing plate two 19.

[0054] During operation, when the fixed block 14 drives the limiting frame 16, the annular clamping plate 161, the air extraction pipe 4 and the gas detection seat 3 to move synchronously, the arc-shaped pressing plate one 18 at the bottom of the limiting frame 16 will contact the arc-shaped end of the arc-shaped pressing plate two 19 on the side wall of the detection platform 1, so that the arc-shaped end of the arc-shaped pressing plate two 19 presses the arc-shaped pressing plate one 18 to a certain extent, and the arc-shaped pressing plate one 18 drives the limiting frame 16, the annular clamping plate 161, the air extraction pipe 4 and the gas detection seat 3 to move upward, thus further improving the air extraction range of the gas and the detection speed of the gas.

[0055] An elastic telescopic column 20 is installed at the bottom of the limiting frame 16. A spring is sleeved on the outer surface of the elastic telescopic column 20. The bottom of the elastic telescopic column 20 is connected to the end face of the extended bracket of the fixed block 14. During operation, when the limiting frame 16 moves upward, the limiting frame 16 will simultaneously pull the elastic telescopic column 20 at its bottom. When the arc-shaped pressing plate one 18 and the arc-shaped pressing plate two 19 are separated, under the elastic force of the elastic telescopic column 20, the limiting frame 16 will return to its initial position. Since there are multiple arc-shaped pressing plates two 19, when the arc-shaped pressing plates two 19 at different positions contact the arc-shaped pressing plate one 18, the detection rate of the tunnel gas is greatly improved, which is beneficial to the excavation of the tunnel.

[0056] As Figure 11 As shown in the figure, a method for detecting gas in a shield tunnel. This detection method uses the above-mentioned gas detection device for a shield tunnel, and includes the following steps:

[0057] S1. Place the detection platform 1 at a suitable position in the tunnel, fix it in the embedded installation hole 201 through an externally connected embedded screw, and fixedly install this detection platform 1 at a suitable place in the tunnel;

[0058] S2. Control the externally connected controller to make the micro-motor drive the air extraction fan 5 inside the air extraction pipe 4 to rotate, so that the air extraction fan 5 sucks the harmful gases deposited near the tunnel floor into the air extraction pipe 4, and the gas detection seat 3 detects and processes the toxic gases. In this way, the toxic gases deposited on the ground can be quickly sucked into the gas detection seat 3.

[0059] The gas detection seat 3 in the step S2 includes a display and an alarm.

[0060] During operation, place the detection platform 1 at a suitable position in the tunnel, fix it in the embedded installation hole 201 through an externally connected embedded screw, and fixedly install this detection platform 1 at a suitable place in the tunnel. Then control the externally connected controller to make the micro-motor drive the air extraction fan 5 inside the air extraction pipe 4 to rotate, so that the air extraction fan 5 sucks the harmful gases deposited near the tunnel floor into the air extraction pipe 4, and the gas detection seat 3 detects and processes the toxic gases. With such a design, the toxic gases deposited on the ground can be quickly sucked into the gas detection seat 3, enabling the harmful gases to be detected immediately when leakage occurs, reducing the possibility of harmful gases entering the air with the wind and endangering the health of the staff, and improving the beneficial effect of the subsequent excavation of the shield tunnel; after the detection platform 1 is installed, and when air enters the air extraction pipe 4, the circular filter plate 6 designed inside the air extraction pipe 4 can block some larger dust particles, preventing the dust particles from entering the gas detection seat 3 along the air extraction pipe 4 and affecting the use of the gas detection seat 3, and also avoiding the problem that larger dust particles touch the air extraction fan 5 and damage the air extraction fan 5;

[0061] When the air extraction fan 5 is working normally, the air extraction fan 5 will drive the reciprocating lead screw 7 at its end to rotate at the same time. The reciprocating lead screw 7 will drive the cleaning unit connected to it to operate. The cleaning unit can not only sweep away the dust particles blocked in front of the circular filter plate 6 at the front end of the air extraction pipe 4, but also dehumidify the front end of the air extraction pipe 4 to avoid the problem that excessive moisture affects the normal detection of the gas detection seat 3; when the reciprocating lead screw 7 rotates, the reciprocating lead screw 7 will drive the slider 8 arranged in a threaded manner with it to move at the same time. The slider 8 will drive the four support rods 9 connected to it to move. The four support rods 9 drive the cleaning ring 10 to move synchronously, so that the cleaning ring 10 moves outward along the inner wall of the air extraction pipe 4. Then the cleaning ring 10 will sweep away the dust particles blocked in front of the circular filter plate 6, preventing too many particles from affecting the air extraction effect of the air extraction pipe 4 and improving the detection effect of harmful gases;

[0062] When the cleaning ring 10 moves on the inner wall of the suction pipe 4, all the elastic rods 12 connected to the cleaning ring 10 will be in a compressed state. When the slider 8 moves forward under the rotation of the reciprocating screw rod 7, and since the reciprocating screw rod 7 extends outside the suction pipe 4, the slider 8 will slowly drive the cleaning ring 10 to separate from the suction pipe 4. When the cleaning ring 10 separates from the suction pipe 4, the elastic rods 12 in the compressed state will recover, driving the cleaning ring 10 to vibrate by a certain amplitude, so that the dust and impurities adhered to the cleaning ring 10 will fall off and drop outside the tunnel. When the reciprocating screw rod 7 drives the slider 8 to move again towards the inside of the suction pipe 4, because the outer wall of the cleaning ring 10 is provided with a rounded corner, it can enter the inside of the suction pipe 4 as soon as possible, and the elastic rods 12 will be in a compressed state again, which is convenient for subsequent continuous cleaning of the inner wall of the suction pipe 4;

[0063] Control the movement of the telescopic end of the reciprocating cylinder 15, so that the telescopic end of the reciprocating cylinder 15 drives the fixed block 14, the suction pipe 4 and the gas detection seat 3 to move synchronously, changing the suction position of the suction pipe 4 and increasing the suction range of the suction pipe 4, so as to solve the problem that some toxic gases deposited on the ground are difficult to be detected when the gas flow rate is low; when the fixed block 14 drives the limit frame 16, the annular clamping plate 161, the suction pipe 4 and the gas detection seat 3 to move synchronously, the arc-shaped pressing plate one 18 at the bottom of the limit frame 16 will contact the arc-shaped end of the arc-shaped pressing plate two 19 on the side wall of the detection platform 1, so that the arc-shaped end of the arc-shaped pressing plate two 19 presses the arc-shaped pressing plate one 18 to a certain extent, driving the limit frame 16, the annular clamping plate 161, the suction pipe 4 and the gas detection seat 3 to move upward, which can further increase the suction range of the gas and improve the gas detection speed.

[0064] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A gas detection device in a shield tunnel, comprising a detection platform (1), characterized in that: Both side walls of the detection platform (1) are fixedly connected with mounting platforms (2). Each mounting platform (2) has a mounting hole (201) on its surface. Through the mounting hole (201), an external embedded screw can be fixedly embedded in the bottom or top of the tunnel. Above the detection platform (1), there is a gas detection seat (3). The lower end surface of the gas detection seat (3) is equipped with symmetrically arranged air extraction pipes (4). Inside each air extraction pipe (4), an air extraction fan (5) is rotatably arranged. The air extraction fan (5) is connected to the output end of an external micro motor. The air extraction fan (5) is used to quickly draw harmful gases with a specific gravity greater than that of air into the air extraction pipe (4). Inside each air extraction pipe (4), an L-shaped support rod (401) is fixedly installed. The air extraction fan (5) is rotatably arranged at the end of the L-shaped support rod (401). Inside the air extraction pipe (4) and on the side of the air extraction fan (5), a circular filter plate (6) is installed. The circular filter plate (6) is used to block large dust particles in the tunnel. On the side of the air extraction fan (5) away from the L-shaped support rod (401), a reciprocating lead screw (7) is installed. A cleaning unit is arranged on the outer peripheral surface of the reciprocating lead screw (7). The cleaning unit is used to clean the inner wall of the air extraction pipe (4). The air extraction pipe (4) is shaped with a large diameter at one end and a small diameter at the other end. The air extraction fan (5) is arranged at the connection of the large diameter and the small diameter in the air extraction pipe (4). The cleaning unit includes a slider (8) threadedly arranged on the reciprocating lead screw (7). Four support rods (9) are fixedly installed on the outer peripheral surface of the slider (8). Cleaning rings (10) are fixedly installed at the ends of the four support rods (9). A cleaning sponge is sleeved on the outer surface of the cleaning ring (10). The cleaning part of the cleaning ring (10) contacts the inner wall of the air extraction pipe (4). Two fixed shafts (101) are installed on the inner wall of the cleaning ring (10). A cleaning shaft (102) is rotatably arranged on the outer wall of the fixed shaft (101). A cleaning sponge is sleeved on the outside of the cleaning shaft (102). The cleaning unit further includes a fixed ring (11) fixedly installed at the end of the support rod (9) away from the slider (8). A plurality of elastic rods (12) arranged in a circumferential array are fixedly installed on the outer wall of the fixed ring (11). A telescopic spring is sleeved on the outer peripheral surface of each elastic rod (12). The cleaning ring (10) is fixedly installed at the end of one group of the elastic rods (12). The outer wall of the cleaning ring (10) is provided with a rounded corner. The reciprocating lead screw (7) extends out of the outside of the air extraction pipe (4).

2. The gas detection device in a shield tunnel according to claim 1, wherein: Above the detection platform (1), a rectangular groove (13) is formed. A fixing block (14) is slidably arranged on the groove wall of the rectangular groove (13). The air extraction pipe (4) is connected to the side wall of the fixing block (14) through a connecting unit. At the edge of the detection platform (1), a reciprocating cylinder (15) is fixedly installed. The telescopic end of the reciprocating cylinder (15) is connected to the side wall of the fixing block (14). At the contact position between the fixing block (14) and the rectangular groove (13), rollers are arranged.

3. The gas detection device in a shield tunnel according to claim 2, wherein: The connecting unit includes a limiting frame (16) slidably arranged on the side wall of the fixing block (14). There are two limiting frames (16), which are symmetrically arranged relative to the fixing block (14). On the side wall of each limiting frame (16), an annular clamping plate (161) is fixedly installed. The annular clamping plate (161) is connected to the outer wall of the air extraction pipe (4).

4. The gas detection device in a shield tunnel according to claim 3, characterized in that: Limiting grooves (17) are formed on both side walls of the fixing block (14). The limiting frame (16) is slidably arranged inside the limiting grooves (17). An arc-shaped pressing plate I (18) is fixedly connected to the bottom of the limiting frame (16). A plurality of arc-shaped pressing plates II (19) are installed on the side wall of the detection platform (1). During the movement of the fixing block (14), the limiting frame (16) and the arc-shaped pressing plate I (18) on its side wall will be driven to move, and the arc-shaped end of the arc-shaped pressing plate I (18) will contact the arc-shaped end of the arc-shaped pressing plate II (19). An elastic telescopic column (20) is installed at the bottom of the limiting frame (16). A spring is sleeved on the outer surface of the elastic telescopic column (20). The bottom of the elastic telescopic column (20) is connected to the end face of the extended bracket of the fixing block (14).

5. A method for gas detection in a shield tunnel, the detection method using a gas detection device in a shield tunnel according to any one of claims 1-4, characterized in that: It includes the following steps: S1. Place the detection platform (1) at a suitable position in the tunnel, and fixedly install it in the installation hole (201) through an externally connected embedded screw, and fixedly install the detection platform (1) at a suitable place in the tunnel. S2. Control the externally connected controller to make the micro motor drive the air extraction fan (5) inside the air extraction pipe (4) to rotate, so that the air extraction fan (5) sucks the harmful gases deposited near the tunnel ground into the air extraction pipe (4), and the gas detection seat (3) detects and processes the toxic gases. In this way, the toxic gases deposited on the ground can be quickly sucked into the gas detection seat (3).

6. The method for detecting gas in a shield tunnel according to claim 5, characterized in that: The gas detection seat (3) in step S2 includes a display and an alarm.

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