Matched train device used after cyclone water film dust removal and electrostatic dust removal of working face of shield tunneling machine

Abstract

The invention discloses a shield tunneling machine working face cyclone water film dust removal and electrostatic dust removal rear matching train device which comprises a cyclone water film dust remover and an electrostatic dust remover which are arranged on a front dust removal train section, and an electrostatic generator and a counter-rotating axial flow fan which are arranged on a rear dust removal train section. The front end of the electrostatic generator is connected with the electrostatic dust collector through a cable bridge, and an air outlet in the rear end of the electrostatic dust collector is connected with an air inlet in the front end of the counter-rotating axial flow fan through an air duct bridge; an air inlet at the front end of the cyclone water film dust remover is connected with a dust collection pipeline system; the dust collection pipeline system is provided with a floating dust space dust collection cover, a transfer point dust collection cover and a plurality of cutter head dust collection short pipes. The dust collection device can move along with movement of the shield working face, a good dust collection state is kept all the time, the dust collection effect is greatly improved in a wet dust collection and electrostatic dust collection combined mode, the air environment of the shield working face is fully improved, and meanwhile dust-containing air is prevented from being exhausted into the atmosphere to pollute the atmospheric environment.

Description

Technical Field

[0001] This invention belongs to the field of tunnel boring machine construction technology, specifically relating to a train device for cyclone water film dust removal and electrostatic dust removal at the working face of a tunnel boring machine. Background Technology

[0002] The tunnel boring machine (TBM) face is one of the main dust-generating areas, primarily consisting of rock dust. This rock dust is mainly produced during processes such as cutting, loading, and transferring. The rock dust produced at the TBM face is mainly composed of SiO2 (silicon dust is highly hazardous) and can significantly impact worker health, equipment wear and tear, and safe production.

[0003] The mainstream dust suppression methods used at the tunnel boring machine (TBM) working face include water injection to soften the rock strata, spraying water, ventilation, and dust collection fans. Current techniques involve dust collection fans located on the train following the TBM, primarily using cyclone dust collectors and bag filters. However, traditional dust suppression methods cannot reduce rock dust concentrations to the required levels. High concentrations of rock dust severely impact workers' physical and mental health, and low visibility is detrimental to safe production. High concentrations of rock dust also increase safety risks and increase wear and tear on mechanical and electrical equipment, reducing its service life.

[0004] As the level of mechanization increases, the amount of dust generated at the tunnel boring machine (TBM) operation point also increases. Dust has the following characteristics: (1) A thin film of air is adsorbed on the surface of the dust, which hinders the agglomeration and settling between dust particles or between water droplets and dust particles; (2) The dispersion of dust increases, and the number of oxygen molecules adsorbed on its surface increases, which accelerates the oxidation and decomposition process of dust; (3) Due to the increased surface area, the free silica in fine rock dust can easily dissolve in human lung cells; (4) Fresh dust generated at the tunneling face is more likely to become charged than dust in the return air duct.

[0005] Currently, the following measures are commonly used to reduce dust at the tunnel boring machine's working face: 1) Water injection softening of rock layers: The injectability of rock masses varies greatly due to factors such as whether the rock mass has sufficient fissures, the water injection pressure of the water supply pipeline, and whether the rock mass has water wettability.

[0006] 2) Spraying water: Spraying dust suppression mainly adopts a combination of internal spraying of the shield machine cutter teeth and external spraying of the cutterhead. Spraying water mist for dust suppression requires high spray pressure and large spray volume. Because the rock mass contains clay minerals, it is easy to muddy and expand when it comes into contact with water, which deteriorates the working face environment. At the same time, the clay rock dust is not effectively captured by water spray and will have an adhesion effect. Rock dust often clogs the nozzles, resulting in poor dust removal effect.

[0007] 3) Ventilation and dust reduction: By strengthening ventilation, rock dust is accelerated to flow downstream. This technology is limited by wind speed, ventilation negative pressure and ventilation resistance and cannot completely solve the dust reduction problem. Moreover, this technology only dilutes and transfers pollutants and discharges dusty air into the atmosphere, without reliably reducing the total amount of rock dust pollutants.

[0008] 4) Dust Collection Fans: Dust collection fans reduce rock dust through the action of a power unit, dust collection unit, and collection unit. Common methods include cyclone dust collectors (poor dust removal efficiency, approximately 70%), bag filters (only suitable for dry dust collection and cannot be combined with wet spraying at the cutting area of ​​the working face; the dust collection unit is prone to clogging, causing bag jamming, and has high operating resistance), and wet scrubbing fans (general dust removal effect and increased air humidity, worsening the working environment). These mechanical dust collection methods do not provide efficient dust removal. To improve dust removal efficiency, the ventilation volume of the dust collection fan is often increased. However, increasing the fan load generates significant operating noise, which is detrimental to safe and civilized production at the working face, and also creates significant airflow disturbances that interfere with orderly ventilation.

[0009] The aforementioned dust removal methods all suffer from technical problems of ineffectiveness and secondary dust generation: suspended rock dust is called floating dust, while settled or collected rock dust is called settling dust. Floating dust and settling dust can transform into each other under different conditions. When subjected to external forces, settling dust can be re-entrained and suspended in the air, resulting in secondary dust generation. Traditional dust collection fans require significant suction power, which can easily lead to improper handling of collected floating dust, resulting in secondary dust generation. Summary of the Invention

[0010] To solve the above-mentioned technical problems, the present invention provides a matching train device for cyclone water film dust removal and electrostatic dust removal on the working face of a tunnel boring machine, which has good dust removal effect, high safety and reliability, and can move with the tunnel boring machine as it moves forward.

[0011] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a supporting train device for cyclone water film dust removal and electrostatic dust removal at the working face of a tunnel boring machine. Several supporting trains are arranged in series on the track laid by the tunnel boring machine. Two adjacent supporting trains are respectively set as a front dust removal train and a rear dust removal train. The front dust removal train is equipped with a cyclone water film dust collector and an electrostatic dust collector. The rear dust removal train is equipped with an electrostatic generator and a counter-rotating axial flow fan arranged side by side on the left and right. The front end of the electrostatic generator is connected to the electrostatic dust collector through a cable tray. The air outlet at the rear end of the electrostatic dust collector is connected to the air inlet at the front end of the counter-rotating axial flow fan through a duct cable tray. The air inlet at the front end of the cyclone water film dust collector is connected to a dust suction pipeline system. The dust suction pipeline system is equipped with a floating dust space suction hood, a transfer point suction hood, and several cutterhead suction short pipes. The cutterhead suction short pipes are located on the front side of the shield and the rear side of the shield cutterhead. The transfer point suction hood is located at the transfer junction of the first and second conveyor belts. The floating dust space suction hood is located in the area with a large amount of floating and sinking in the rear space of the shield machine.

[0012] Both the dust collection hood for floating dust spaces and the dust collection hood for transfer points include an umbrella-shaped folding frame coaxially mounted on the suction pipe. The extension and folding of the umbrella-shaped folding frame is driven by a hollow hydraulic cylinder coaxially mounted on the suction pipe.

[0013] The cyclone water film dust collector includes a horizontally arranged outer cylinder and a dust collection water tank. The front and rear ends of the outer cylinder are equipped with blocking plates. An inner cylinder is arranged coaxially inside the outer cylinder, and a cylindrical cavity is formed between the outer circle of the inner cylinder and the inner circle of the outer cylinder. A spiral guide plate is provided between the inner cylinder and the outer cylinder to form a spiral airflow channel in the cylindrical cavity. The air inlet at the front end of the spiral airflow channel is connected to the air outlet of the dust collection pipeline system. The dust collection water tank is located below the outer cylinder and extends backward to below the electrostatic precipitator. A rectangular hole communicating with the dust collection water tank is opened along the length direction at the bottom of the outer cylinder. The water level in the dust collection water tank is inside the outer cylinder and has an air passage gap with the lowest point of the inner cylinder.

[0014] The electrostatic precipitator includes a dust collection box, which contains multiple identical sets of equipment arranged from front to back. Each set of electrostatic precipitators includes multiple dust collection plates arranged vertically along the front-to-back direction. A corona electrode is provided between any two adjacent dust collection plates. The upper ends of all the corona electrode lines are connected to a high-voltage bus terminal, which is connected to an electrostatic generator. A grounding wire is connected to the lower side of the dust collection box. The bottom of the dust collection box is open and fixedly connected to the top of the dust collection water tank. A water inlet for adding water to the dust collection water tank is provided in the middle of the rear end of the dust collection box, and a water inlet sealing plug is provided at the water inlet.

[0015] The lower part of the dust collection water tank is equipped with a mud discharge screw along the front-to-back direction. The front and rear ends of the mud discharge screw are rotatably connected to the front and rear side plates of the dust collection water tank, respectively. An explosion-proof motor reducer is provided on the outer side of the front end of the dust collection water tank. The output shaft of the explosion-proof motor reducer is connected to the front end of the mud discharge screw. A mud discharge pipe is provided on the rear side plate of the dust collection water tank below the mud discharge screw, and a mud discharge valve is provided on the mud discharge pipe.

[0016] The electrostatic generator includes an industrial frequency power input line, a regulator, an industrial frequency step-up transformer, a high-voltage rectifier, and high-voltage output terminals; the electrostatic generator is connected to an input cable tray at the rear end.

[0017] The counter-rotating axial flow fan includes a drive motor and a rigid duct arranged horizontally in the front-to-back direction. The rigid duct is equipped with a first set of counter-rotating blades and a second set of counter-rotating blades, both of which are connected to the drive motor. The front end of the rigid duct is connected to the rear end of the duct bridge. The rear end of the rigid duct is equipped with a conical airflow diffuser that is wider at the rear and narrower at the front.

[0018] The dust collection piping system includes a main dust collection pipe. The rear end of the main dust collection pipe is connected to the air inlet at the front end of the spiral airflow channel. The main dust collection pipe extends forward along the outer side of the rear supporting train in front of the front section of the dust removal train. The front end of the main dust collection pipe is connected to the first, second, and third dust collection pipes via a four-way pipe joint at the front side of the foremost rear supporting train. The dust space dust collection hood is connected to the air inlet of the first dust collection pipe. The first dust collection pipe is equipped with a first air volume regulating valve. The transfer point dust collection hood is connected to the air inlet of the second dust collection pipe. The second dust collection pipe is equipped with a second air volume regulating valve. The third dust collection pipe extends forward to the shield of the tunnel boring machine. The air inlet of the third dust collection pipe is connected to a distribution pipe fixed on the shield. The rear ends of several cutterhead dust collection short pipes are all connected to the distribution pipe. The air inlets of the several cutterhead dust collection short pipes are flared mouths that are larger at the front and smaller at the back. Each cutterhead dust collection short pipe is equipped with a third air volume regulating valve.

[0019] Compared with the prior art, the present invention has the following advantages by adopting the above technical solution: (1) During the construction process, the cutterhead of the tunnel boring machine generates a large amount of rock dust. Under the action of the counter-rotating axial flow fan, the air carrying the rock dust is collected through the dust collection hood of the cutterhead, the dust collection hood at the transfer point, and several short dust collection pipes of the cutterhead. The dust then passes through the dust collection pipeline system, the cyclone water film dust collector, the electrostatic precipitator, the air duct bridge, and the rigid air duct in sequence. Finally, the clean air is sprayed out by the airflow diffuser. The dust is mainly removed by the cyclone water film dust collector and the electrostatic precipitator.

[0020] The front and rear dust removal trains are any two adjacent sections from the rear supporting train, which meets the requirements for the tunnel boring machine to advance after dust removal, ensuring continuous dust removal operations.

[0021] (2) Both the cutterhead dust collection hood and the transfer point dust collection hood are retractable dust collection hoods. The dust collection hood creates a negative pressure in a local area to draw high concentrations of rock dust into the cyclone water film dust collector. The dust collection hood operates in an unsealed manner, with the dust source located in the incompletely sealed area outside the dust collection hood opening. The transfer point dust collection hood is located at the transfer junction of the first and second conveyor belts, and the dust collection hood for the floating dust space is located in the area with a large floating volume in the rear space of the tunnel boring machine. The shape of the dust collection hood mainly considers the size of the reserved space after the tunnel boring machine space integration. The transfer point dust collection hood can use a small retractable dust collection hood; the rear space dust collection hood can use a large retractable dust collection hood. Since it is not suitable to arrange dust collection hoods on the rear side of the cutterhead, several cutterhead dust collection short pipes (hollow steel pipes) are set up. The front end of each cutterhead dust collection short pipe is a flared mouth to maximize the dust collection area in the limited space. The umbrella-shaped folding frame of the dust collection hood for the cutterhead and the transfer point meets the requirement of short-distance follow-up of the roadheader's operation by the dust removal equipment. The center of the dust collection hood is a hollow suction steel pipe (sucking pipe); a hydraulic cylinder is installed on the suction steel pipe to drive the retraction of the umbrella-shaped folding frame; the hydraulic cylinder drives the umbrella-shaped folding frame to reciprocate, opening and folding the dust collection hood; the umbrella-shaped folding frame is made of high-toughness steel lightweight frame; a flexible air lining is fixed to the umbrella-shaped folding frame with wire; the operation of the hydraulic cylinder drives the frame retraction rod to move, thereby opening and closing the umbrella-shaped folding frame, thus achieving the following: under working conditions, the dust collection hood opens to meet the suction effect; under non-working conditions, the dust collection hood retracts to allow the cutting head to pass through non-working positions. That is, the dust collection hood retracts when in a narrow position and opens when in a working position; it retracts to protect the dust collection hood when the cutting part passes through a complex position, and opens when the cutting part and the dust collection hood are in the working position.

[0022] Each dust hood has a regulating butterfly valve installed at a certain distance on the suction steel pipe at the rear. The opening and closing degree of the butterfly valve is adjusted according to the amount of dust generated, so that the dust hood operates under optimal conditions, achieving the goals of saving electricity, reducing noise, minimizing airflow disturbance, and improving dust removal efficiency. In addition, foam atomizing nozzles can also be installed on the umbrella-shaped folding frame of the dust hood.

[0023] (3) After dust removal, the supporting train runs on the track to meet the requirement that the supporting train follows the working face of the tunnel boring machine for a long distance to advance. Atomizing nozzles are installed at the fixed position of the tunnel boring machine cutterhead. The atomizing nozzles use a spray foam generator to replace water spray to increase the surface area of ​​the spray, increase the suspension time of the spray foam, and increase the adsorption effect of rock dust, while reducing the explosiveness of the rock dust. The chemical ratio of the sprayed foam liquid can be adjusted according to the wettability, coagulation and adhesion of the dust being removed. For hydrophilic dust with good wettability (generally ordinary rock dust and rock dust with low coalification degree), water-based foaming agents can be used. For hydrophobic dust with poor wettability (generally oil shale rock dust and rock dust with high coalification degree), in order to accelerate the wettability of the liquid (foam liquid) on the dust, different proportions of wetting agents can be added according to the different wetting angles to reduce the surface tension between the solid and liquid, increase the foam affinity of the dust, and improve the dust removal effect. It can achieve better dust removal effect with a lower spray volume, reduce water spray volume, reduce mudding on the working surface, and reduce the perceived humidity of the working surface.

[0024] The spray medium for both internal and external spraying was improved by replacing water with an aqueous solution containing rosin foaming agent and surfactant, which was then sprayed onto the working face through atomizing nozzles. The mixing ratio was adjusted according to the differences in the hydrophilicity and hydrophobicity of the rock dust to be removed, giving the foam higher dust collection performance. The pressurized air and compressed liquid from the shield tunneling compressed air system worked together to achieve the foaming effect through atomization.

[0025] (4) A cyclone water film dust collector is installed at the front of the dust removal train. The dust-laden airflow is introduced tangentially along the front end of the outer cylinder and flows along the spiral airflow channel. When the airflow impacts the water surface in the dust collection tank at a high speed, some dust particles are absorbed by the water, and water droplets are stirred up. The airflow carries water droplets and rotates, using the centrifugal force to provide centrifugal acceleration, accelerating the movement of rock dust and water droplets towards the cylinder wall. Under the action of gravity, the deposits on the cylinder wall accumulate in the dust collection tank. The dust-laden airflow flows continuously through several spiral airflow channels and is purified multiple times, so that more than 70% of the rock dust is captured and separated. This cyclone water film dust collector has three dust removal functions: cyclone, water film, and water bath. At the same time, this dust collector is a wet dust collector with high dust removal efficiency. It can improve the dust removal effect when the air volume is small, thereby reducing the operating noise of the fan and improving the comfort of personnel at the working face from noise pollution.

[0026] (5) An electrostatic precipitator is installed at the rear of the front dust removal train to further purify the airflow using electrostatic dust removal. The airflow purified by the cyclone water film dust collector still contains uncaptured rock dust and dust-laden droplets. When this airflow enters the electrostatic precipitator, it can not only remove uncaptured rock dust, but also act as an electrostatic dehydrator to remove water droplets. Dust particles are usually negatively charged, and their charge comes from the friction of the rock mass during crushing. The amount of charge depends on temperature and humidity. When the temperature rises, the charge increases, and when the humidity rises, the charge decreases. Electrostatic dust removal can remove fine dust, negatively charged droplets, and foam. The underground production airflow passing through the above dust removal train can optimize the working environment of the working face (including reducing inhalable dust and reducing return air humidity). The dust suppression foam can reduce the explosiveness of rock dust at the working face, reduce the rated power of the dust removal fan to reduce the noise at the working face, and at the same time, the front and rear dust removal trains can advance along the track with the working face to achieve the effect of stabilizing the dust removal conditions.

[0027] (6) This invention employs a wet dust removal method throughout the entire production line, from foam dust removal at the working surface using atomizing nozzles to sequentially passing through cyclone water film dust removal, electrostatic removal of covered rock dust foam, and electrostatic removal of mist droplets. The final dust removal product is water-rock mud. The mud collects at the bottom of the dust collection tank and is discharged from the tank by a mud discharge screw driven by an explosion-proof motor reducer. The discharged mud is then collected into waterproof ton bags by a collection device and transported by a supporting material vehicle to the mud sedimentation tank of the ground sewage treatment plant. This achieves the effect of avoiding secondary dust generation. Simultaneously, water is added to the dust collection tank through the water inlet.

[0028] (7) The rear dust removal train is equipped with a counter-rotating axial flow fan, which serves as the main power source for dust collection in the entire train system. The counter-rotating axial flow fan is small in size and its airflow can be adjusted by adjusting the blade angle. The power of the variable frequency motor is adjusted according to the amount of dust generated to achieve energy saving. At the same time, an electrostatic generator is installed on the rear supporting train, arranged side by side with the counter-rotating axial flow fan.

[0029] (8) A counter-rotating axial flow fan is installed on the rear dust removal train as the main power source for dust collection of the entire train. The counter-rotating axial flow fan is small in size and its air volume can be adjusted by adjusting the blade angle. The power of the variable frequency motor is adjusted according to the amount of dust generated to achieve energy saving. At the same time, an electrostatic generator is installed on the rear dust removal train, arranged side by side with the counter-rotating axial flow fan.

[0030] (9) The usual ventilation method for tunnel boring machines is forced ventilation through a flexible steel frame duct. Due to the participation of dust removal fans and dust hoods, the forced ventilation method is improved to "long-pressure short-extraction local ventilation". Compared with forced ventilation, "long-pressure short-extraction local ventilation" has the following advantages: 1. It can quickly remove rock dust and pass it through the dust removal system; 2. The polluted air can move along a fixed path; 3. It keeps the dust content of the entire working face at a low level; 4. The workers are always upstream of the fresh airflow and breathe clean air. "Long-pressure short-extraction" ventilation can achieve "air-dust separation" and "air-pollution separation", separating the functions of creating a good working environment (dust control) from ensuring ventilation safety (oxygen supply and dilution of harmful gases); at the same time, it plans a clear flow path for airflow and pollutants, avoiding the spread of polluted air and secondary pollution; it has a great advantage in occupational health protection and safe production level.

[0031] In summary, this invention installs the dust removal equipment on the train following the tunnel boring machine's working face, allowing it to move with the working face and maintain good dust collection at all times. By combining wet and electrostatic dust removal, the dust removal effect is greatly improved. The horizontal cyclone water film dust collector can achieve good dust removal efficiency with a relatively small suction volume, reaching a dust removal rate of 80%. The electrostatic precipitator can achieve a dust removal rate of 99.9% for rock dust, atomized foam, and water droplets, which are typically negatively charged, while simultaneously collecting foam and droplets. This significantly improves the air environment at the tunnel boring machine's working face and prevents dust-laden air from being released into the atmosphere and polluting the atmosphere. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the elevation structure of the present invention; Figure 2 for Figure 1 Enlarged views of the equipment on the front and rear dust removal trains; Figure 3 for Figure 1 Enlarged view of the central vacuum duct system; Figure 4 for Figure 2 Schematic diagram of the three-dimensional structure of the cyclone water film dust collector; Figure 5 for Figure 2 Sectional view of AA; Figure 6 for Figure 2 BB section view; Figure 7 for Figure 2 A three-dimensional structural diagram of a medium-sized electrostatic precipitator; Figure 8 for Figure 3 A schematic diagram showing the connection between the central dust hood in its extended state and the hydraulic cylinder; Figure 9 for Figure 3 A schematic diagram showing the connection between the folded dust hood and the hydraulic cylinder. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] like Figures 1-9 As shown, the shield tunneling machine working face has a cyclone water film dust removal and electrostatic dust removal supporting train device. Several supporting trains 1 are arranged in series on the track laid by the shield tunneling machine. Two adjacent supporting trains 1 are respectively set as the front dust removal train 2 and the rear dust removal train 3. The front dust removal train 2 is equipped with a cyclone water film dust collector 4 and an electrostatic dust collector 5. The rear dust removal train 3 is equipped with an electrostatic generator 16 and a counter-rotating axial flow fan 17 arranged side by side on the left and right. The front end of the electrostatic generator 16 is connected to the electrostatic dust collector 5 through a cable tray 18. The air outlet at the rear end of the electrostatic dust collector 5 is connected to the air inlet at the front end of the counter-rotating axial flow fan 17 through a wind tunnel cable tray 19. The air inlet at the front end of the cyclone water film dust collector 4 is connected to a dust suction pipeline system 6. The dust suction pipeline system 6 is equipped with a floating dust space suction hood 7, a transfer point suction hood 8, and several cutterhead suction short pipes 9. The cutterhead suction short pipes 9 are located on the front side of the shield 10 and the rear side of the shield cutterhead 11. The transfer point suction hood 8 is located at the transfer junction of the primary conveyor belt 12 and the secondary conveyor belt 13. The floating dust space suction hood 7 is located in the area with a large floating and sinking volume in the rear space of the shield machine.

[0036] Both the floating dust space dust hood 7 and the transfer point dust hood 8 are umbrella-shaped folding frames 20 coaxially mounted on the suction pipe. The extension and folding of the umbrella-shaped folding frame 20 is driven by a hollow hydraulic cylinder 22 coaxially mounted on the suction pipe 21.

[0037] The cyclone water film dust collector 4 includes a horizontally arranged outer cylinder 23 and a dust collection water tank 28. The front and rear ends of the outer cylinder 23 are provided with blocking plates 24. An inner cylinder 25 is arranged coaxially inside the outer cylinder 23. A cylindrical cavity is formed between the outer circle of the inner cylinder 25 and the inner circle of the outer cylinder 23. A spiral guide plate 26 is provided between the inner cylinder 25 and the outer cylinder 23 to form a spiral airflow channel in the cylindrical cavity. The air inlet at the front end of the spiral airflow channel is connected to the air outlet of the dust collection pipeline system 6. The dust collection water tank 28 is located below the outer cylinder 23 and extends backward to below the electrostatic precipitator 5. A rectangular hole communicating with the dust collection water tank 28 is opened along the length direction at the bottom of the outer cylinder 23. The water level in the dust collection water tank 28 is inside the outer cylinder 23 and has an air passage gap with the lowest point of the inner cylinder 25.

[0038] The electrostatic precipitator 5 includes a dust collection box 29. The dust collection box 29 has multiple sets of identical structures arranged from front to back. Each set of electrostatic precipitators 5 includes multiple dust collection plates 30 arranged vertically in the front-back direction. A corona electrode wire 31 is provided between any two adjacent dust collection plates 30. The upper ends of all corona electrode wires 31 are connected to a high-voltage bus terminal 32. The high-voltage bus terminal 32 is connected to the electrostatic generator 16. A grounding wire 33 is connected to the lower side of the dust collection box 29. The bottom of the dust collection box 29 is open and fixedly connected to the top of the dust collection water tank 28. A water inlet 34 for adding water to the dust collection water tank 28 is provided in the middle of the rear end of the dust collection box 29. A water inlet sealing plug is provided at the water inlet 34.

[0039] The dust collection water tank 28 has a mud discharge screw 35 at the bottom along the front-to-back direction. The front and rear ends of the mud discharge screw 35 are rotatably connected to the front and rear side plates of the dust collection water tank 28, respectively. An explosion-proof motor reducer 36 is provided on the outer side of the front end of the dust collection water tank 28. The output shaft of the explosion-proof motor reducer 36 is connected to the front end of the mud discharge screw 35. A mud discharge pipe 37 is provided on the rear side plate of the dust collection water tank 28 below the mud discharge screw 35. A mud discharge valve is provided on the mud discharge pipe 37.

[0040] The electrostatic generator 16 includes a power frequency power inlet 38, a power conditioner 39, a power frequency step-up transformer 40, a high-voltage rectifier 41, and a high-voltage outlet terminal 42. The electrostatic generator 16 is connected to an inlet cable tray 49 at its rear end.

[0041] The counter-rotating axial flow fan 17 includes a drive motor 44 and a rigid air duct 43 arranged horizontally in the front-to-back direction. The rigid air duct 43 is provided with a first set of counter-rotating blades 45 and a second set of counter-rotating blades 46, both of which are connected to the drive motor 44. The front end of the rigid air duct 43 is connected to the rear end of the air duct bridge 19. The rear end of the rigid air duct 43 is provided with a conical airflow diffuser 47 that is thicker at the rear and thinner at the front.

[0042] The dust collection piping system 6 includes a main dust collection pipe 14. The rear end of the main dust collection pipe 14 is connected to the air inlet at the front end of the spiral airflow channel. The main dust collection pipe 14 extends forward along the outer side of the rear auxiliary train 1 in front of the front section of the dust removal train 2. The front end of the main dust collection pipe 14 is connected to a first dust collection pipe 50, a second dust collection pipe 51, and a third dust collection pipe 52 via a four-way pipe connector 15 on the front side of the foremost rear auxiliary train 1. The dust space dust collection hood 7 is connected to the air inlet of the first dust collection pipe 50. The first dust collection pipe 50 is equipped with a first airflow rate. The regulating valve 53, the transfer point dust hood 8 is connected to the air inlet of the second dust suction pipe 51, the second dust suction pipe 51 is equipped with a second air volume regulating valve 54, the third dust suction pipe 52 extends forward to the shield 10 of the tunnel boring machine, the air inlet of the third dust suction pipe 52 is connected to the air distribution pipe 55 fixed on the shield 10, the rear ends of several cutterhead dust suction short pipes 9 are all connected to the air distribution pipe 55, the air inlets of several cutterhead dust suction short pipes 9 are flared mouths 56 that are larger at the front and smaller at the back, and each cutterhead dust suction short pipe 9 is equipped with a third air volume regulating valve 57.

[0043] The working principle of this invention and its beneficial effects are as follows: (1) During the construction process, the cutterhead 11 of the tunnel boring machine generates a large amount of rock dust. Under the action of the counter-rotating axial flow fan 17, the air carrying the rock dust is collected by the cutterhead dust collection hood, the transfer point dust collection hood 8 and several cutterhead dust collection short pipes 9, and then passes through the dust collection pipeline system 6, the cyclone water film dust collector 4, the electrostatic precipitator 5, the air duct bridge 19, and the rigid air duct 43. Finally, the clean air is sprayed out by the airflow diffuser 47. The dust is mainly removed by the cyclone water film dust collector 4 and the electrostatic precipitator 5.

[0044] The front dust removal train 2 and the rear dust removal train 3 are any two adjacent sections of the rear supporting train 1, which meets the requirements for the tunnel boring machine to advance after dust removal and ensures that the dust removal operation is carried out continuously.

[0045] (2) Both the cutterhead dust collection hood and the transfer point dust collection hood 8 are retractable dust collection hoods that create negative pressure in a local area to draw high concentrations of rock dust into the cyclone water film dust collector 4. The dust collection hoods operate in an unsealed manner, with the dust source located in the incompletely sealed area outside the dust collection hood opening. The transfer point dust collection hood 8 is located at the transfer junction of the first conveyor belt 12 and the second conveyor belt 13, and the dust collection hood 7 is located in the area with a large amount of floating and sinking in the rear space of the tunnel boring machine. The shape of the dust collection hoods mainly considers the size of the reserved space after the tunnel boring machine space is integrated. The transfer point dust collection hood 8 can use a small retractable dust collection hood; the rear space dust collection hood can use a large retractable dust collection hood. Since it is not suitable to arrange dust collection hoods on the rear side of the cutterhead 11, several cutterhead dust collection short pipes 9 (hollow steel pipes) are set up. The front end of each cutterhead dust collection short pipe 9 is a flared mouth to maximize the dust collection area in the limited space.

[0046] The umbrella-shaped folding frame 20 of the cutterhead dust suction hood and the transfer point dust suction hood 8 meets the requirements of the dust removal equipment to follow the operation of the roadheader over short distances. The center of the dust suction hood is a hollow suction steel pipe (suction pipe 21); a hydraulic cylinder 22 is installed on the suction steel pipe to drive the umbrella-shaped folding frame 20 to retract; the hydraulic cylinder 22 drives the umbrella-shaped folding frame 20 to reciprocate to open and fold the dust suction hood; the umbrella-shaped folding frame 20 is made of high-toughness steel lightweight frame; a flexible air cloth is fixed to the umbrella-shaped folding frame 20 with iron wire; the operation of the hydraulic cylinder 22 drives the frame retraction rod to move, thereby driving the opening and retraction of the umbrella-shaped folding frame 20, so that the dust suction hood opens under working conditions to meet the suction effect, and retracts under non-working conditions to allow the cutting head to pass through non-working positions. That is, the dust hood retracts when it is in a narrow position and opens when it is in a working position; it retracts to protect the dust hood when the cutting part passes through a complex position, and opens the dust hood when the cutting part and the dust hood are in the working position.

[0047] Each dust hood has a suction pipe with adjustable airflow butterfly valves 48 installed at a certain distance at the rear. The opening and closing degree of the butterfly valves 48 is adjusted according to the amount of dust generated, so that the dust hood operates under optimal conditions, achieving the goals of saving electricity, reducing noise, minimizing airflow disturbance, and improving dust removal efficiency. In addition, foam atomizing nozzles can also be installed on the umbrella-shaped folding frame 20 of the dust hood.

[0048] (3) After dust removal, the supporting train 1 runs on the track to meet the requirement that the supporting train 1 follows the working face of the tunnel boring machine for a long distance. Atomizing nozzles are installed at the fixed position of the tunnel boring machine cutterhead. The atomizing nozzles use a spray foam generator to replace water spray to increase the surface area of ​​the spray, increase the suspension time of the spray foam, and increase the adsorption effect of rock dust, while reducing the explosiveness of the rock dust. The chemical ratio of the sprayed foam liquid can be adjusted according to the wettability, coagulation and adhesion of the dust being removed. For hydrophilic dust with good wettability (generally ordinary rock dust and rock dust with low coalification degree), water-based foaming agents can be used. For hydrophobic dust with poor wettability (generally oil shale rock dust and rock dust with high coalification degree), in order to accelerate the wettability of the liquid (foam liquid) on the dust, different proportions of wetting agents can be added according to the different wetting angles to reduce the surface tension between the solid and liquid, increase the foam affinity of the dust, and improve the dust removal effect. It can achieve better dust removal effect with a lower spray volume, reduce water spray volume, reduce mudding on the working surface, and reduce the perceived humidity of the working surface.

[0049] The spray medium for both internal and external spraying was improved by replacing water with an aqueous solution containing rosin foaming agent and surfactant, which was then sprayed onto the working face through atomizing nozzles. The mixing ratio was adjusted according to the differences in the hydrophilicity and hydrophobicity of the rock dust to be removed, giving the foam higher dust collection performance. The pressurized air and compressed liquid from the shield tunneling compressed air system worked together to achieve the foaming effect through atomization.

[0050] (4) A cyclone water film dust collector 4 is installed at the front of the dust removal train 2. The dust-laden airflow is introduced tangentially along the front end of the outer cylinder 23 and flows along the spiral airflow channel. When the airflow impacts the water surface in the dust collection water tank 28 at a high speed, some dust particles are absorbed by the water, and water droplets are stirred up. The airflow carries water droplets and rotates, using the centrifugal force to provide centrifugal acceleration, accelerating the movement of rock dust and water droplets towards the cylinder wall. Under the action of gravity, the deposits on the cylinder wall accumulate in the dust collection water tank 28. The dust-laden airflow flows continuously through several spiral airflow channels and is purified multiple times, so that more than 70% of the rock dust is captured and separated. The cyclone water film dust collector 4 has three dust removal functions: cyclone, water film, and water bath. At the same time, the dust collector is a wet dust collector with high dust removal efficiency. It can improve the dust removal effect when the air volume is small, thereby reducing the operating noise of the fan and improving the comfort of personnel at the working face from noise pollution.

[0051] (5) An electrostatic precipitator 5 is installed on the rear side of the front dust removal train 2 to further purify the airflow using electrostatic dust removal. The airflow purified by the cyclone water film dust collector 4 still contains uncaptured rock dust and dust-laden droplets. This airflow enters the electrostatic precipitator 5, which not only removes the uncaptured rock dust but also acts as an electrostatic dehydrator to remove water droplets. Dust particles are usually negatively charged, and their charge originates from the friction of coal and rock during crushing. The amount of charge depends on temperature and humidity; the charge increases with increasing temperature and decreases with increasing humidity. Electrostatic dust removal can remove fine dust, negatively charged droplets, and foam. The underground production airflow through the above dust removal trains can optimize the working environment at the working face (including reducing inhalable dust and reducing return air humidity). The dust suppression foam can reduce the explosiveness of rock dust at the working face and reduce the rated power of the dust removal fan to reduce noise at the working face. At the same time, the front dust removal train 2 and the rear dust removal train 3 can advance along the return air roadway or the track of the tunneling material car line with the working face, which can achieve the effect of stabilizing dust removal conditions.

[0052] (6) This invention employs a wet dust removal method throughout the entire production line, from foam dust removal at the working surface using atomizing nozzles to sequentially passing through cyclone water film dust removal, electrostatic removal of covered rock dust foam, and electrostatic removal of mist droplets. The final dust removal product is water-rock dust slurry. The slurry collects at the bottom of the dust collection tank 28 and is discharged from the dust collection tank 28 by a slurry discharge screw 35 driven by an explosion-proof motor reducer 36. The discharged slurry is then collected into watertight ton bags by a collection device and transported by a supporting material vehicle to the slurry sedimentation tank of the ground sewage treatment plant. This achieves the effect of avoiding secondary dust generation. At the same time, water is added to the dust collection tank 28 through the water inlet 34.

[0053] (7) The dust removal train 3 in the rear section is equipped with a counter-rotating axial flow fan, which serves as the main power source for dust collection in the entire train system. The counter-rotating axial flow fan 17 is small in size and its air volume can be adjusted by adjusting the blade angle. The power of the variable frequency motor is adjusted according to the amount of dust generated to achieve energy saving. At the same time, an electrostatic generator is installed on the rear supporting train 1 in the rear section, arranged side by side with the counter-rotating axial flow fan.

[0054] (8) The rear dust removal train 3 is equipped with a counter-rotating axial flow fan 17, which serves as the main power source for dust collection in the entire train system. The counter-rotating axial flow fan 17 is small in size and its airflow can be adjusted by adjusting the blade angle. The power of the variable frequency motor is adjusted according to the amount of dust generated to achieve energy saving. At the same time, an electrostatic generator 16 is arranged on the rear dust removal train 3, arranged side by side with the counter-rotating axial flow fan 17.

[0055] (9) The usual ventilation method for tunnel boring machines is forced ventilation through a flexible steel frame duct. Due to the participation of dust removal fans and dust hoods, the forced ventilation method is improved to "long-pressure short-extraction local ventilation". Compared with forced ventilation, "long-pressure short-extraction local ventilation" has the following advantages: 1. It can quickly remove rock dust and pass it through the dust removal system; 2. The polluted air can move along a fixed path; 3. It keeps the dust content of the entire working face at a low level; 4. The workers are always upstream of the fresh airflow and breathe clean air. "Long-pressure short-extraction" ventilation can achieve "air-dust separation" and "air-pollution separation", separating the functions of creating a good working environment (dust control) from ensuring ventilation safety (oxygen supply and dilution of harmful gases); at the same time, it plans a clear flow path for airflow and pollutants, avoiding the spread of polluted air and secondary pollution; it has a great advantage in occupational health protection and safe production level.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A train system for cyclone water film dust removal and electrostatic dust removal at the working face of a tunnel boring machine (TBM), wherein several tandem train cars are arranged on the tracks laid during TBM construction, characterized in that: The two adjacent rear supporting trains are respectively set as the front dust removal train and the rear dust removal train. The front dust removal train is equipped with a cyclone water film dust collector and an electrostatic dust collector. The rear dust removal train is equipped with an electrostatic generator and a counter-rotating axial flow fan arranged side by side on the left and right. The front end of the electrostatic generator is connected to the electrostatic dust collector through a cable tray. The air outlet at the rear end of the electrostatic dust collector is connected to the air inlet at the front end of the counter-rotating axial flow fan through a duct cable tray. The air inlet at the front end of the cyclone water film dust collector is connected to a dust suction pipeline system. The dust suction pipeline system is equipped with a floating dust space suction hood, a transfer point suction hood, and several cutterhead suction short pipes. The cutterhead suction short pipes are located on the front side of the shield and the rear side of the shield cutterhead. The transfer point suction hood is located at the transfer junction of the first and second conveyor belts. The floating dust space suction hood is located in the area with a large amount of floating and sinking in the rear space of the shield machine.

2. The matching train device for cyclone water film dust removal and electrostatic dust removal at the tunnel boring machine working face according to claim 1, characterized in that: Both the dust collection hood for floating dust spaces and the dust collection hood for transfer points include an umbrella-shaped folding frame coaxially mounted on the suction pipe. The extension and folding of the umbrella-shaped folding frame is driven by a hollow hydraulic cylinder coaxially mounted on the suction pipe.

3. The matching train device for cyclone water film dust removal and electrostatic dust removal at the tunnel boring machine working face according to claim 2, characterized in that: The cyclone water film dust collector includes a horizontally arranged outer cylinder and a dust collection water tank. The front and rear ends of the outer cylinder are equipped with blocking plates. An inner cylinder is arranged coaxially inside the outer cylinder, and a cylindrical cavity is formed between the outer circle of the inner cylinder and the inner circle of the outer cylinder. A spiral guide plate is provided between the inner cylinder and the outer cylinder to form a spiral airflow channel in the cylindrical cavity. The air inlet at the front end of the spiral airflow channel is connected to the air outlet of the dust collection pipeline system. The dust collection water tank is located below the outer cylinder and extends backward to below the electrostatic precipitator. A rectangular hole communicating with the dust collection water tank is opened along the length direction at the bottom of the outer cylinder. The water level in the dust collection water tank is inside the outer cylinder and has an air passage gap with the lowest point of the inner cylinder.

4. The matching train device for cyclone water film dust removal and electrostatic dust removal at the tunnel boring machine working face according to claim 3, characterized in that: The electrostatic precipitator includes a dust collection box, which contains multiple identical sets of equipment arranged from front to back. Each set of electrostatic precipitators includes multiple dust collection plates arranged vertically along the front-to-back direction. A corona electrode is provided between any two adjacent dust collection plates. The upper ends of all the corona electrode lines are connected to a high-voltage bus terminal, which is connected to an electrostatic generator. A grounding wire is connected to the lower side of the dust collection box. The bottom of the dust collection box is open and fixedly connected to the top of the dust collection water tank. A water inlet for adding water to the dust collection water tank is provided in the middle of the rear end of the dust collection box, and a water inlet sealing plug is provided at the water inlet.

5. The matching train device for cyclone water film dust removal and electrostatic dust removal at the tunnel boring machine working face according to claim 4, characterized in that: The lower part of the dust collection water tank is equipped with a mud discharge screw along the front-to-back direction. The front and rear ends of the mud discharge screw are rotatably connected to the front and rear side plates of the dust collection water tank, respectively. An explosion-proof motor reducer is provided on the outer side of the front end of the dust collection water tank. The output shaft of the explosion-proof motor reducer is connected to the front end of the mud discharge screw. A mud discharge pipe is provided on the rear side plate of the dust collection water tank below the mud discharge screw, and a mud discharge valve is provided on the mud discharge pipe.

6. The matching train device for cyclone water film dust removal and electrostatic dust removal at the working face of the tunnel boring machine according to claim 1, characterized in that: The electrostatic generator includes an industrial frequency power input line, a regulator, an industrial frequency step-up transformer, a high-voltage rectifier, and high-voltage output terminals; the electrostatic generator is connected to an input cable tray at the rear end.

7. The matching train device for cyclone water film dust removal and electrostatic dust removal at the working face of the tunnel boring machine according to claim 1, characterized in that: The counter-rotating axial flow fan includes a drive motor and a rigid duct arranged horizontally in the front-to-back direction. The rigid duct is equipped with a first set of counter-rotating blades and a second set of counter-rotating blades, both of which are connected to the drive motor. The front end of the rigid duct is connected to the rear end of the duct bridge. The rear end of the rigid duct is equipped with a conical airflow diffuser that is wider at the rear and narrower at the front.

8. The matching train device for cyclone water film dust removal and electrostatic dust removal at the working face of the tunnel boring machine according to claim 1, characterized in that: The dust collection piping system includes a main dust collection pipe. The rear end of the main dust collection pipe is connected to the air inlet at the front end of the spiral airflow channel. The main dust collection pipe extends forward along the outer side of the rear supporting train in front of the front section of the dust removal train. The front end of the main dust collection pipe is connected to the first, second, and third dust collection pipes via a four-way pipe joint at the front side of the foremost rear supporting train. The dust space dust collection hood is connected to the air inlet of the first dust collection pipe. The first dust collection pipe is equipped with a first air volume regulating valve. The transfer point dust collection hood is connected to the air inlet of the second dust collection pipe. The second dust collection pipe is equipped with a second air volume regulating valve. The third dust collection pipe extends forward to the shield of the tunnel boring machine. The air inlet of the third dust collection pipe is connected to a distribution pipe fixed on the shield. The rear ends of several cutterhead dust collection short pipes are all connected to the distribution pipe. The air inlets of the several cutterhead dust collection short pipes are flared mouths that are larger at the front and smaller at the back. Each cutterhead dust collection short pipe is equipped with a third air volume regulating valve.

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