Device and method for detecting gas in shield tunnel

Abstract

The invention belongs to the technical field of gas detection, and particularly relates to a device and method for detecting gas in a shield tunnel, the device comprises a detection platform, the two side walls of the detection platform are fixedly connected with mounting tables, the surface of each mounting table is provided with a mounting hole, and an external embedded screw can be fixedly embedded in the bottom or top of the tunnel through the mounting holes. A gas detection seat is arranged above the detection platform, symmetrically arranged exhaust pipes are mounted on the lower end surface of the gas detection seat, an exhaust fan is rotationally arranged in each exhaust pipe, and the exhaust fans are connected with the output end of an external micro motor; the air suction fan is used for sucking harmful gas with the specific gravity larger than that of air into the air suction pipe as soon as possible; and the micro motor drives the exhaust fan in the exhaust pipe to rotate, so that the exhaust fan sucks harmful gas deposited near the tunnel ground into the exhaust pipe, and the harmful gas is detected through the gas detection seat.

Description

Technical Field

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

[0002] The basic working principle of the shield machine is that the shield machine excavates the soil while advancing along the tunnel axis. The cylindrical component of the shield machine, the shield, plays a temporary support role for the excavated tunnel section that has not yet been lined. Tunnel construction is prone to produce flammable gases and toxic and harmful gases. These gases are retained 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] The prior art also proposes some solutions for tunnel gas detection. For example, a Chinese patent application with publication number CN117248902A discloses a tunnel harmful gas detection and advance detection device, including legs, brackets, water-gas separation box, direction adjustment components, drilling components, gas detection components and internal auxiliary components. The water-gas separation box is fixed on the legs, the gas detection component is fixed on the water-gas separation box, the gas detection component is connected to the water-gas separation box, and the internal auxiliary components are arranged in the water-gas separation box. This invention belongs to the field of tunnel construction technology, specifically refers to a tunnel harmful gas detection and advance detection device; it solves the problem that the tunnel harmful gas detection and advance detection device on the market cannot automatically adjust the drill rod angle according to the drill rod deflection size.

[0004] Although the above technical solution solves the problem that the advance detection device cannot automatically adjust the drill rod angle according to the drill rod deflection size, there are still other problems in specific use. For example, there are many types of gases in the shield tunnel construction process, and these toxic gases include carbon monoxide, methane, hydrogen sulfide, sulfur dioxide and dust particles; Some toxic gases have a specific gravity greater than that of air, while others have a specific gravity less than that of air. For example, harmful gases such as hydrogen sulfide are heavier than air. These toxic gases with a specific gravity greater than that of air will be deposited near the tunnel floor, making it more difficult to detect these gases.

[0005] To this end, the present invention provides a gas detection device and method in a shield tunnel. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0007] The technical solution adopted by the present invention to solve its technical problem is: a gas detection device in a shield tunnel described in the present invention includes a detection platform, both side walls of the detection platform are fixedly connected with a mounting platform, and the surface of each mounting platform is provided with a mounting hole, through which an external embedded screw can be fixedly embedded in the bottom or top of the tunnel, a gas detection seat is arranged above the detection platform, and the lower end surface of the gas detection seat is installed with symmetrically arranged exhaust pipes, and an exhaust fan is rotatably arranged inside each of the exhaust pipes, and the exhaust fan is connected to the output end of an external micro motor, and the exhaust fan is used to draw harmful gases with a specific gravity greater than that of air into the exhaust pipe as soon as possible, so that the harmful gases can be detected at the first time.

[0008] Preferably, an L-shaped support rod is fixedly installed inside each of the exhaust pipes, the exhaust fan is rotatably arranged at the end of the L-shaped support rod, and a circular filter plate is installed inside the exhaust pipe and on the side of the exhaust fan, and the circular filter plate is used to block large dust particles in the tunnel.

[0009] Preferably, a reciprocating screw is installed on the side of the exhaust fan away from the L-shaped support rod, and a cleaning unit is provided on the outer peripheral surface of the reciprocating screw. The cleaning unit is used to clean the inner wall of the exhaust pipe. The shape of the exhaust pipe is a large diameter at one end and a small diameter at the other end. The exhaust fan is arranged at the connection between the large diameter and the small diameter in the exhaust pipe.

[0010] Preferably, the cleaning unit includes a slider threaded on a reciprocating screw, four support rods are fixedly mounted on the outer circumference of the slider, cleaning rings are fixedly mounted on the ends of the four support rods, a cleaning sponge is sleeved on the outer surface of the cleaning ring, a cleaning portion of the cleaning ring is in contact with the inner wall of the exhaust pipe, two fixed shafts are installed on the inner wall of the cleaning ring, a cleaning shaft is rotatably mounted on the outer wall of the fixed shaft, and a cleaning sponge is sleeved on the outside of the cleaning shaft.

[0011] Preferably, the cleaning unit also includes a fixing ring fixedly installed on the end of the support rod away from the slider, a plurality of elastic rods arranged in a circular array are fixedly installed on the outer wall of the fixing ring, a telescopic spring is sleeved on the outer circumferential surface of each elastic rod, the cleaning ring is fixedly installed on the end of one group of the elastic rods, the outer wall of the cleaning ring is provided with rounded corners, and the reciprocating screw extends out of the outside of the exhaust pipe.

[0012] Preferably, a rectangular groove is opened above the detection platform, a fixed block is slidably provided on the groove wall of the rectangular groove, the exhaust pipe is connected to the side wall of the fixed block through a connecting 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, and a roller is provided at the contact position between the fixed block and the rectangular groove.

[0013] Preferably, the connecting unit includes a limit frame slidably arranged on the side wall of the fixed block, two limit frames are arranged symmetrically with respect to the fixed block, and the side wall of each limit frame is fixedly installed with an annular clamping plate, and the annular clamping plate is connected to the outer wall of the exhaust pipe.

[0014] Preferably, both side walls of the fixed block are provided with limiting grooves, the limiting frame is slidably arranged inside the limiting grooves, an arc-shaped pressure plate 1 is fixedly connected to the bottom of the limiting frame, and a plurality of arc-shaped pressure plates 2 are installed on the side walls of the detection platform. When the fixed block moves, the limiting frame and the arc-shaped pressure plate 1 on its side walls will be driven to move, and the arc-shaped end of the arc-shaped pressure plate 1 will contact the arc-shaped end of the arc-shaped pressure plate 2.

[0015] Preferably, an elastic telescopic column is installed at the bottom of the limit frame, a spring is sleeved on the outer surface of the elastic telescopic column, and the bottom of the elastic telescopic column is connected to the end face of the bracket extended from the fixed block; when working, when the limit frame moves upward, the limit frame will simultaneously pull the elastic telescopic column at its bottom, and when the arc pressure plate 1 and the arc pressure plate 2 are separated, the limit frame will return to its initial position under the elastic force of the elastic telescopic column. Since multiple arc pressure plates 2 are provided, the arc pressure plates 2 and 1 at different positions are in contact with each other, which greatly improves the detection rate of tunnel gas and is beneficial to tunnel excavation.

[0016] Preferably, a method for detecting gas in a shield tunnel, the method using the above-mentioned gas detection device in a shield tunnel, comprises the following steps: S1. Place the detection platform at a suitable position in the tunnel, and fix it into the installation hole through an external embedded screw, and fix the detection platform at a suitable position in the tunnel; S2. Control the external controller so that the micro motor drives the exhaust fan inside the exhaust pipe to rotate, so that the exhaust fan draws the harmful gas deposited near the tunnel ground into the exhaust pipe, and detects and processes the toxic gas through the gas detection seat, so that the toxic gas deposited on the ground can be drawn into the gas detection seat as soon as possible.

[0017] Preferably, the gas detection seat in step S2 includes a display and an alarm.

[0018] The beneficial effects of the present invention are as follows: 1. The gas detection device and method in a shield tunnel described in the present invention draws harmful gases deposited near the tunnel ground into the exhaust pipe through an exhaust fan, and detects and processes the toxic gases through a gas detection seat. With such a design, the toxic gases deposited on the ground can be drawn into the gas detection seat as quickly as possible, so that the harmful gases can be detected at the first time when leakage occurs, reducing the possibility of harmful gases entering the air with the wind and endangering the health of workers, and improving the beneficial effects of subsequent excavation of the shield tunnel.

[0019] 2. The gas detection device and method in a shield tunnel described in the present invention can slowly drive the cleaning ring to separate from the exhaust pipe through the slider. When the cleaning ring is separated from the exhaust pipe, the elastic rod in the compressed state recovers, which can drive the cleaning ring to vibrate with a certain amplitude, so that the dust and impurities adhered to the cleaning ring are shaken off and fall to the outside of the tunnel. When the reciprocating screw drives the slider to move closer to the inside of the exhaust pipe again, since the outer wall of the cleaning ring is provided with rounded corners, it can enter the inside of the exhaust pipe as soon as possible and make the elastic rod compressed again, which can facilitate the subsequent cleaning of the inner wall of the exhaust pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] Figure 1 is a stereogram of the present invention; Figure 2 It is a partial structural schematic diagram of the air extraction pipe in the present invention; Figure 3 It is a partial structural schematic diagram of the fixed block in the present invention; Figure 4 It is a schematic diagram of the cross-sectional structure of the air extraction pipe in the present invention; Figure 5 It is a schematic diagram of the reciprocating screw structure in the present invention; Figure 6 It is a partial structural schematic diagram of the cleaning ring in the present invention; Figure 7 It is a schematic diagram of the cleaning shaft structure in the present invention; Figure 8 It is a side view structural schematic diagram of the present invention; Fig. 9 It is a partial structural schematic diagram of the limiting frame in the present invention; Fig.10 It is a partial structural schematic diagram of the arc-shaped pressing plate 1 and the arc-shaped pressing plate 2 in the present invention; Fig.11 It is a flow chart of the method in the present invention.

[0022] In the figure: 1. detection platform; 2. mounting table; 201. mounting hole; 3. gas detection seat; 4. exhaust pipe; 401. L-shaped support rod; 5. exhaust fan; 6. circular filter plate; 7. reciprocating screw rod; 8. slider; 9. support rod; 10. cleaning ring; 11. fixing ring; 12. elastic rod; 13. rectangular groove; 14. fixing block; 15. reciprocating cylinder; 16. limiting frame; 161. annular clamping plate; 17. limiting groove; 18. arc pressure plate one; 19. arc pressure plate two; 20. elastic telescopic column. DETAILED DESCRIPTION

[0023] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0024] like Figures 1 to 4 As shown, a gas detection device in a shield tunnel described in an embodiment of the present invention comprises a detection platform 1, both side walls of the detection platform 1 are fixedly connected with mounting platforms 2, and the surface of each mounting platform 2 is provided with mounting holes 201, through which an external embedded screw can be fixedly embedded in the bottom or top of the tunnel, a gas detection seat 3 is arranged above the detection platform 1, and a symmetrically arranged exhaust pipe 4 is installed on the lower end surface of the gas detection seat 3, and an exhaust fan 5 is rotatably arranged inside each of the exhaust pipes 4, and the exhaust fan 5 is connected to the output end of an external micro motor, and the exhaust fan 5 is used to draw harmful gases with a specific gravity greater than that of air into the exhaust pipe 4 as soon as possible, so that the harmful gases can be detected at the first time; During the work, flammable gas and toxic and harmful gas will be generated in the shield tunnel construction process. Some of these toxic gases have a higher specific gravity than air, and some have a lower specific gravity than air. These toxic gases with a higher specific gravity than air will be deposited near the tunnel ground, which makes it more troublesome to detect these gases. Therefore, this gas detection device can be used for detection; First, the gas detection device of the present invention is installed, and the detection platform 1 is placed at a suitable position in the tunnel, and is fixedly embedded in the installation hole 201 by an external embedded screw, and the detection platform 1 is fixedly installed at a suitable place in the tunnel, and then the external controller is controlled to make the micro motor drive the exhaust fan 5 inside the exhaust pipe 4 to rotate, so that the exhaust fan 5 draws the harmful gas deposited near the tunnel ground into the exhaust pipe 4, and detects and processes the toxic gas through the gas detection seat 3. The way in which the gas detection seat 3 detects the gas in the tunnel is the existing technology, and no unnecessary details are made in the embodiments of the present invention. With such a design, the toxic gas deposited on the ground can be drawn into the gas detection seat 3 as soon as possible, so that the harmful gas can be detected in the first time when a leak occurs, reducing the possibility that the harmful gas enters the air with the wind and endangers the health of the workers, and improving the beneficial effect of the subsequent excavation of the shield tunnel; It should be noted that the suitable locations of the tunnel mentioned in the present invention are dangerous places where gas leakage is easy, such as the tunnel entrance, the middle of the tunnel, the tunnel bifurcation, and the blasting site; It should also be noted that the gas detection device can also be installed on the top of the tunnel by using an external embedded screw to install the mounting platform 2 and the detection platform 1, so that the gas detection seat 3 can also detect toxic gases with a specific gravity less than that of air, thereby improving the practicality of the present invention.

[0025] like Figures 2 to 8 As shown, an L-shaped support rod 401 is fixedly installed inside each of the exhaust pipes 4, and the exhaust fan 5 is rotatably set at the end of the L-shaped support rod 401. A circular filter plate 6 is installed inside the exhaust pipe 4 and on the side of the exhaust 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 air is taken in from the exhaust pipe 4, some larger dust particles can be blocked by the circular filter plate 6 designed inside the exhaust pipe 4, so as to prevent the dust particles from entering the gas detection seat 3 along the exhaust pipe 4 and affecting the use of the gas detection seat 3, and also to prevent the larger dust particles from touching the exhaust fan 5 and causing damage to the exhaust fan 5.

[0026] A reciprocating screw 7 is installed on the side of the exhaust fan 5 away from the L-shaped support rod 401, and a cleaning unit is provided on the outer circumference of the reciprocating screw 7, and the cleaning unit is used to clean the inner wall of the exhaust pipe 4. The shape of the exhaust pipe 4 is a large diameter at one end and a small diameter at the other end. The exhaust fan 5 is arranged at the connection between the large diameter and the small diameter in the exhaust pipe 4; During operation, when the exhaust fan 5 works normally, the exhaust fan 5 will simultaneously drive the reciprocating screw 7 at its end to rotate, and the reciprocating screw 7 will drive the cleaning unit connected to it to operate. The cleaning unit can not only remove the dust particles blocked at the front end of the exhaust pipe 4, that is, the front end of the circular filter plate 6, but also dehumidify the front end of the exhaust pipe 4 to avoid the problem of large amounts of moisture affecting the normal detection of the gas detection seat 3.

[0027] The cleaning unit includes a slider 8 threadedly arranged on the reciprocating screw 7, and four support rods 9 are fixedly installed on the outer circumferential surface of the slider 8, and cleaning rings 10 are fixedly installed at the ends of the four support rods 9, and the cleaning part of the cleaning ring 10 is in contact with the inner wall of the exhaust pipe 4; when working, when the reciprocating screw 7 rotates, the reciprocating screw 7 will simultaneously drive the slider 8 threadedly arranged thereon to move, and the slider 8 will drive the four support rods 9 connected thereto to move, and 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 exhaust pipe 4, and then the cleaning ring 10 will sweep away the dust particles blocked at the front end of the circular filter plate 6, so as to avoid that a large number of particles affect the exhaust effect of the exhaust pipe 4, thereby improving the detection effect of harmful gases; The inner wall of the cleaning ring 10 is provided with two fixed shafts 101, and the outer wall of the fixed shaft 101 is rotatably provided with a cleaning shaft 102, and the outer part of the cleaning shaft 102 is sleeved with a cleaning sponge; It should be noted that, refer to the attached Figure 7 As shown, 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, 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 the cleaning shaft 102 itself will rotate at a certain angle while moving along the inner wall of the exhaust pipe 4, thereby improving the effect of cleaning the particles on the inner wall of the exhaust pipe 4, and absorbing the water droplets condensed on the inner wall of the exhaust pipe 4, thereby preventing the water droplets condensed on the inner wall of the exhaust pipe 4 from flowing along the inner wall to the side of the gas detection seat 3, causing problems in the normal use of the gas detection seat 3.

[0028] like Figures 4 to 9 As shown, the cleaning unit also includes a fixing ring 11 fixedly mounted on the end of the support rod 9 away from the slider 8, and a plurality of elastic rods 12 arranged in a circular array are fixedly mounted on the outer wall of the fixing ring 11, and a telescopic spring is sleeved on the outer circumferential surface of each of the elastic rods 12, and the cleaning ring 10 is fixedly mounted on the end of one group of the elastic rods 12, and the outer wall of the cleaning ring 10 is provided with a rounded corner, and the reciprocating screw rod 7 extends out of the outside of the exhaust pipe 4; during operation, when the cleaning ring 10 moves on the inner wall of the exhaust pipe 4, all the elastic rods 12 connected to the cleaning ring 10 will be in a compressed state, and when the slider 8 is under the rotation of the reciprocating screw rod 7 When moving forward, and because the reciprocating screw rod 7 extends out of the outside of the exhaust pipe 4, the slider 8 will slowly drive the cleaning ring 10 to separate from the exhaust pipe 4. When the cleaning ring 10 is separated from the exhaust pipe 4, the elastic rod 12 in the compressed state is restored, which will drive the cleaning ring 10 to vibrate with a certain amplitude, so that the dust and impurities adhered to the cleaning ring 10 are shaken off and fall to the outside of the tunnel. When the reciprocating screw rod 7 drives the slider 8 to move closer to the inside of the exhaust pipe 4 again, since the outer wall of the cleaning ring 10 is provided with rounded corners, it can enter the inside of the exhaust pipe 4 as soon as possible and make the elastic rod 12 compressed again, which can facilitate the subsequent cleaning of the inner wall of the exhaust pipe 4.

[0029] Specifically, when the air flow velocity in the tunnel is low, the mixing and diffusion efficiency of harmful gases in the tunnel may be reduced, and the detection efficiency may be reduced. Therefore, the present invention further proposes the following embodiments; a rectangular groove 13 is provided above the detection platform 1, and a fixed block 14 is slidably provided on the groove wall of the rectangular groove 13. The exhaust pipe 4 is connected to the side wall of the fixed block 14 through a connecting unit. A reciprocating cylinder 15 is fixedly installed at the edge of the detection platform 1, and the telescopic end of the reciprocating cylinder 15 is connected to the side wall of the fixed block 14. A roller is provided at the contact position between the fixed block 14 and the rectangular groove 13; 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 fixed block 14, the exhaust pipe 4 and the gas detection seat 3 to move synchronously, so that the exhaust position of the exhaust pipe 4 changes, and the exhaust range of the exhaust pipe 4 is increased. In this way, the problem of toxic gases that are partially deposited on the ground being difficult to detect when the gas flow rate is low can be solved.

[0030] The connecting unit includes a limit frame 16 slidably arranged on the side wall of the fixed block 14, and two limit frames 16 are arranged symmetrically relative to the fixed block 14. The side wall of each limit frame 16 is fixedly installed with an annular clamping plate 161, and the annular clamping plate 161 is connected to the outer wall of the exhaust pipe 4; when working, when the fixed block 14 moves inside the rectangular groove 13, the fixed block 14 will simultaneously drive the limit frames 16 and the annular clamping plate 161 on both sides and the exhaust pipe 4 to move, and the exhaust pipe 4 drives the gas detection seat 3 to move synchronously, thereby improving the detection speed of gas in the tunnel.

[0031] like Figures 6 to 9 As shown, both side walls of the fixed block 14 are provided with limiting grooves 17, the limiting frame 16 is slidably arranged inside the limiting grooves 17, the bottom of the limiting frame 16 is fixedly connected with an arc-shaped pressing plate 18, and the side walls of the detection platform 1 are installed with a plurality of arc-shaped pressing plates 19. When the fixed block 14 moves, it will drive the limiting frame 16 and the arc-shaped pressing plate 18 of its side wall to move, and the arc-shaped end of the arc-shaped pressing plate 18 will contact the arc-shaped end of the arc-shaped pressing plate 19; During operation, when the fixed block 14 drives the limit frame 16, the annular clamp 161, the exhaust pipe 4 and the gas detection seat 3 to move synchronously, the arc pressure plate 18 at the bottom of the limit frame 16 will contact the arc end of the arc pressure plate 2 19 on the side wall of the detection platform 1, so that the arc end of the arc pressure plate 2 19 presses the arc pressure plate 1 18 to a certain extent, so that the arc pressure plate 1 18 drives the limit frame 16, the annular clamp 161, the exhaust pipe 4 and the gas detection seat 3 to move upward, which can further increase the gas extraction range and improve the gas detection speed.

[0032] An elastic telescopic column 20 is installed at the bottom of the limit frame 16, and 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 bracket end face extended from the fixed block 14. During operation, when the limit frame 16 moves up, the limit frame 16 will simultaneously pull the elastic telescopic column 20 at its bottom. When the arc pressure plate 18 and the arc pressure plate 2 19 are separated, the limit frame 16 will return to its initial position under the elastic force of the elastic telescopic column 20. Since a plurality of arc pressure plates 19 are provided, when the arc pressure plates 1 19 and the arc pressure plates 1 18 at different positions are in contact with each other, the detection rate of tunnel gas is greatly improved, which is beneficial to the excavation of the tunnel.

[0033] like Fig.11 As shown, a method for detecting gas in a shield tunnel is provided. The method adopts the above-mentioned gas detection device in a shield tunnel, and comprises the following steps: S1. Place the detection platform 1 at a suitable position in the tunnel, and fix it into the mounting hole 201 by means of an external embedded screw, and fix the detection platform 1 at a suitable position in the tunnel; S2. Control the external controller so that the micro motor drives the exhaust fan 5 inside the exhaust pipe 4 to rotate, so that the exhaust fan 5 draws the harmful gas deposited near the tunnel ground into the exhaust pipe 4, and detects and processes the toxic gas through the gas detection seat 3, so that the toxic gas deposited on the ground can be drawn into the gas detection seat 3 as soon as possible.

[0034] The gas detection seat 3 in step S2 includes a display and an alarm.

[0035] During operation, the detection platform 1 is placed at a suitable position in the tunnel, and is fixedly embedded in the mounting hole 201 by an external embedded screw, and the detection platform 1 is fixedly installed at a suitable position in the tunnel, and then the external controller is controlled to make the micro motor drive the exhaust fan 5 inside the exhaust pipe 4 to rotate, so that the exhaust fan 5 draws the harmful gas deposited near the tunnel ground into the exhaust pipe 4, and detects and processes the toxic gas through the gas detection seat 3. With such a design, the toxic gas deposited on the ground can be drawn into the gas detection seat 3 as soon as possible, so that the harmful gas can be discharged when a leak occurs. Leakage can be detected immediately, reducing the possibility of harmful gases entering the air with the wind and endangering the health of workers, and improving the beneficial effect of subsequent excavation of the shield tunnel; after the detection platform 1 is installed, and air is taken into the exhaust pipe 4, the circular filter plate 6 designed inside the exhaust pipe 4 can block some larger dust particles, preventing dust particles from entering the gas detection seat 3 along the exhaust pipe 4 and affecting the use of the gas detection seat 3, and also preventing larger dust particles from touching the exhaust fan 5 and causing damage to the exhaust fan 5; When the exhaust fan 5 is working normally, the exhaust fan 5 will simultaneously drive the reciprocating screw rod 7 at its end to rotate, and the reciprocating screw rod 7 will drive the cleaning unit connected thereto 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, the front end of the circular filter plate 6, but also dehumidify the front end of the exhaust pipe 4 to avoid the problem that too much moisture affects the normal detection of the gas detection seat 3; when the reciprocating screw rod 7 rotates, the reciprocating screw rod 7 will simultaneously drive the slider 8 threadedly arranged thereon to move, and the slider 8 will drive the four support rods 9 connected thereto to move, and 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 exhaust pipe 4, and then the cleaning ring 10 will sweep away the dust particles blocked at the front end of the circular filter plate 6, to avoid that a large number of particles affect the exhaust effect of the exhaust pipe 4, thereby improving the detection effect of harmful gases; When the cleaning ring 10 moves on the inner wall of the exhaust 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 out of the outside of the exhaust pipe 4, the slider 8 will slowly drive the cleaning ring 10 to separate from the exhaust pipe 4. When the cleaning ring 10 is separated from the exhaust pipe 4, the elastic rod 12 in the compressed state recovers, which will drive the cleaning ring 10 to vibrate with a certain amplitude, so that the dust and impurities adhered to the cleaning ring 10 are shaken off and fall to the outside of the tunnel. When the reciprocating screw rod 7 drives the slider 8 to move closer to the inside of the exhaust pipe 4 again, since the outer wall of the cleaning ring 10 is provided with rounded corners, it can enter the inside of the exhaust pipe 4 as soon as possible, and make the elastic rod 12 compressed again, which can facilitate the subsequent cleaning of the inner wall of the exhaust pipe 4. 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 exhaust pipe 4 and the gas detection seat 3 to move synchronously, so that the exhaust position of the exhaust pipe 4 changes, and the exhaust range of the exhaust pipe 4 is improved. In this way, the problem that some toxic gases deposited on the ground are difficult to be detected under low gas flow rate can be solved; when the fixed block 14 drives the limit frame 16, the annular clamping plate 161, the exhaust pipe 4 and the gas detection seat 3 to move synchronously, the arc-shaped pressure plate 1 18 at the bottom of the limit frame 16 will contact the arc-shaped end of the arc-shaped pressure plate 2 19 on the side wall of the detection platform 1, so that the arc-shaped end of the arc-shaped pressure plate 2 19 presses the arc-shaped pressure plate 1 18 to a certain extent, so that the arc-shaped pressure plate 1 18 drives the limit frame 16, the annular clamping plate 161, the exhaust pipe 4 and the gas detection seat 3 to move upward, which can further improve the exhaust range of the gas and improve the gas detection speed.

[0036] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached 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), and the surface of each mounting platform (2) is provided with mounting holes (201), through which an external embedded screw can be fixedly embedded in the bottom or top of the tunnel. A gas detection seat (3) is arranged above the detection platform (1), and the lower end surface of the gas detection seat (3) is provided with symmetrically arranged exhaust pipes (4), and each exhaust pipe (4) is rotatably provided with an exhaust fan (5), which is connected to the output end of an external micro motor, and is used to quickly draw harmful gases with a specific gravity greater than that of air into the exhaust pipe (4).

2. A gas detection device in a shield tunnel according to claim 1, characterized in that: An L-shaped support rod (401) is fixedly installed inside each of the exhaust pipes (4); the exhaust fan (5) is rotatably arranged at the end of the L-shaped support rod (401); a circular filter plate (6) is installed inside the exhaust pipe (4) and on the side of the exhaust fan (5); the circular filter plate (6) is used to block large dust particles in the tunnel.

3. A gas detection device in a shield tunnel according to claim 2, characterized in that: A reciprocating screw (7) is installed on the side of the exhaust fan (5) away from the L-shaped support rod (401), and a cleaning unit is provided on the outer peripheral surface of the reciprocating screw (7), and the cleaning unit is used to clean the inner wall of the exhaust pipe (4). The shape of the exhaust pipe (4) is that one end has a large diameter and the other end has a small diameter, and the exhaust fan (5) is arranged at the connection between the large diameter and the small diameter in the exhaust pipe (4).

4. A gas detection device in a shield tunnel according to claim 3, characterized in that: The cleaning unit comprises a slider (8) threadedly arranged on a reciprocating screw (7); four support rods (9) are fixedly mounted on the outer peripheral surface of the slider (8); cleaning rings (10) are fixedly mounted at the ends of the four support rods (9); a cleaning sponge is sleeved on the outer surface of the cleaning ring (10); a cleaning portion of the cleaning ring (10) contacts the inner wall of the exhaust pipe (4); two fixed shafts (101) are mounted on the inner wall of the cleaning ring (10); a cleaning shaft (102) is rotatably mounted on the outer wall of the fixed shaft (101); a cleaning sponge is sleeved on the outside of the cleaning shaft (102).

5. A gas detection device in a shield tunnel according to claim 4, characterized in that: The cleaning unit further comprises a fixing ring (11) fixedly mounted on the end of the support rod (9) away from the slider (8); a plurality of elastic rods (12) arranged in a circular array are fixedly mounted on the outer wall of the fixing ring (11); a telescopic spring is sleeved on the outer peripheral surface of each of the elastic rods (12); the cleaning ring (10) is fixedly mounted on the end of one group of the elastic rods (12); the outer wall of the cleaning ring (10) is provided with a rounded corner; and the reciprocating screw rod (7) extends out of the outside of the exhaust pipe (4).

6. A gas detection device in a shield tunnel according to claim 4, characterized in that: A rectangular groove (13) is provided above the detection platform (1), a fixed block (14) is slidably provided on the groove wall of the rectangular groove (13), the air extraction pipe (4) is connected to the side wall of the fixed block (14) via 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 fixed block (14), and a roller is provided at the contact position between the fixed block (14) and the rectangular groove (13).

7. A gas detection device in a shield tunnel according to claim 6, characterized in that: The connection unit comprises a limit frame (16) slidably arranged on a side wall of the fixed block (14), two limit frames (16) are provided and are symmetrically arranged relative to the fixed block (14), and an annular clamping plate (161) is fixedly mounted on the side wall of each limit frame (16), and the annular clamping plate (161) is connected to the outer wall of the exhaust pipe (4).

8. A gas detection device in a shield tunnel according to claim 7, characterized in that: The two side walls of the fixed block (14) are provided with limit grooves (17), the limit frame (16) is slidably arranged inside the limit grooves (17), the bottom of the limit frame (16) is fixedly connected with an arc-shaped pressure plate 1 (18), and the side walls of the detection platform (1) are installed with a plurality of arc-shaped pressure plates 2 (19), and when the fixed block (14) moves, it will drive the limit frame (16) and the arc-shaped pressure plate 1 (18) on its side wall to move, and the arc-shaped end of the arc-shaped pressure plate 1 (18) will contact the arc-shaped end of the arc-shaped pressure plate 2 (19); the bottom of the limit frame (16) is installed with an elastic telescopic column (20), the outer surface of the elastic telescopic column (20) is sleeved with a spring, and the bottom of the elastic telescopic column (20) is connected to the end face of the bracket extending from the fixed block (14).

9. A method for detecting gas in a shield tunnel, the method using a gas detection device in a shield tunnel as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Place the detection platform (1) at a suitable position in the tunnel, and fix it into the mounting hole (201) by means of an external embedded screw, and fix the detection platform (1) at a suitable position in the tunnel; S2, controlling the external controller so that the micro motor drives the exhaust fan (5) inside the exhaust pipe (4) to rotate, so that the exhaust fan (5) draws the harmful gas deposited near the tunnel ground into the exhaust pipe (4), and detects and processes the toxic gas through the gas detection seat (3), so that the toxic gas deposited on the ground can be drawn into the gas detection seat (3) as soon as possible.

10. A method for detecting gas in a shield tunnel according to claim 9, characterized in that: The gas detection seat (3) in step S2 comprises a display and an alarm.

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