Anti-backflow ventilation system and method for vertical shaft raise boring machine construction

Abstract

The invention relates to the field of mine engineering, tunnel construction and vertical shaft tunneling, in particular to an anti-backflow ventilation system and method for vertical shaft raise boring machine construction. The system is applied to an in-well platform at the junction of a vertical shaft and a tunnel and comprises an injection ventilation module, a ventilation conveying module, a monitoring control module and an anti-backflow guarantee module. The injection ventilation module is used for generating a negative pressure area to suck contaminated air on the working face and conveying the contaminated air to the vertical shaft. The ventilation conveying module communicates with the injection ventilation module and the vertical shaft, provides a channel for dirty air conveying, and dynamically adjusts the length along with the depth of the vertical shaft. The monitoring control module is electrically connected with the injection ventilation module and the anti-backflow guarantee module and is used for monitoring working condition parameters of the ventilation system in real time and intelligently regulating and controlling the modules to operate; the backflow prevention guarantee module is arranged on the ventilation conveying module and used for automatically blocking a dirty air backflow path when the airflow stops or is reversed. By constructing a collaborative ventilation mode of positive pressure supply, negative pressure collection and intelligent regulation and control, dirty air backflow is completely eradicated.

Description

Technical Field

[0001] This invention relates to the fields of mining engineering, tunnel construction and shaft excavation technology, and in particular to a backflow prevention ventilation system and method for shaft raising drilling rig construction. Background Technology

[0002] Raised shaft drilling is a mainstream advanced technology in the field of vertical and inclined shaft excavation. Its core process is "drilling pilot holes from top to bottom and enlarging holes from bottom to top to form a well". It is widely used in underground engineering fields such as mining, water conservancy and hydropower, and transportation tunnels.

[0003] Throughout the entire construction cycle, especially during the pilot hole drilling, blasting and reaming, and equipment operation phases, the downhole working face continuously generates a large amount of pollutants, including high-concentration dust, blasting fumes (containing harmful gases such as carbon monoxide and nitrogen oxides), and diesel exhaust. At the same time, the working environment is enclosed and poorly ventilated, which easily leads to the accumulation of polluted air. This not only seriously threatens the personal safety and health of construction personnel, but also reduces visibility at the working face and affects the normal operation of equipment. Therefore, building an efficient and reliable mechanical ventilation system is an essential safety guarantee for raise shaft drilling operations. Its core requirement is to force fresh airflow to the working face while timely and directionally expelling polluted air to the outside of the well.

[0004] Currently, the main ventilation methods used in raise boring machine (Raid) operations are divided into three types: forced ventilation, extraction ventilation, and hybrid ventilation. Each of these three methods has its limitations and is difficult to adapt to the dynamic and complex working conditions of Raid drilling. 1. Forced ventilation delivers fresh air directly to the work surface through the ventilation duct, which can quickly dilute pollutants. However, the polluted air needs to be naturally diffused and discharged along the roadway. The diffusion speed is slow and the range is wide, which can easily pollute the entire construction passage and make it difficult to completely eliminate ventilation dead spots. 2. Exhaust ventilation directly draws out polluted air from the working face and exhausts it. It is highly targeted in smoke and dust removal. However, in operations such as pilot hole drilling, it is difficult to accurately control the distance between the exhaust port and the working face, which can easily create ventilation blind spots. Especially for long-distance tunnel or deep well construction, the ventilation efficiency drops significantly. 3. Although hybrid ventilation combines the advantages of the first two methods, its system structure is complex, the equipment investment cost is high, the pipeline layout is cumbersome, and the adaptability is poor, making it difficult to meet the construction needs of dynamic tunneling of raise shaft drilling rigs.

[0005] Regarding the aforementioned issue of sludge backflow, existing prevention and control measures have significant shortcomings and are insufficient to meet the safety requirements of raised shaft operations: 1. Reliance on manual ventilation management (such as strictly prohibiting arbitrary ventilation shutdowns and strengthening inspections) is subject to uncertainties such as human error and untimely response, resulting in low reliability of prevention and control. 2. Setting up a backup power supply or backup fan can be started in case of a failure of the main system, but the switching process takes a certain amount of time, and cannot achieve instantaneous protection, making it difficult to deal with the risk of instantaneous sewage backflow; 3. Simple check valve plates are installed in the ventilation duct. These valve plates are mostly made of plastic, canvas and other materials. In the harsh environment of dampness, dust and large temperature difference in the well, they are prone to sticking, aging and deformation, resulting in poor sealing. They cannot withstand the large back pressure difference that may occur during the raise shaft operation, and the anti-backflow effect is unstable and unreliable.

[0006] In summary, in the field of vertical and inclined shaft excavation, raise boring machine (RBM) construction is a mainstream advanced technology. Its core process includes "drilling pilot holes from top to bottom and enlarging the hole from bottom to top to form the shaft," and it is widely used in underground engineering projects such as mining, water conservancy and hydropower, and transportation tunnels. However, during construction, especially during pilot hole drilling, blasting enlargement, and equipment operation, a large amount of pollutants are generated at the underground working face, such as high-concentration dust, blasting fumes (containing harmful gases such as carbon monoxide and nitrogen oxides), and diesel exhaust. Due to the enclosed working environment and poor ventilation, these polluted air particles easily accumulate, seriously threatening the safety and health of construction personnel, while also affecting visibility at the working face and the normal operation of equipment. Therefore, constructing an efficient and reliable mechanical ventilation system is an essential safety guarantee for raise boring machine construction. Existing ventilation methods, such as forced-in, exhaust, and hybrid systems, each have limitations and are difficult to adapt to the dynamic and complex working conditions of raise boring construction. In particular, the problem of sludge backflow is highly likely to occur in complex construction environments, and existing measures are insufficient for effective prevention and control, such as in scenarios involving abnormal ventilation system shutdowns, overlapping operations on multiple work faces, significant impacts from natural wind pressure, and instantaneous airflow turbulence after blasting operations. Existing prevention and control measures have obvious shortcomings and are insufficient to meet the safety requirements of raised shaft construction. Summary of the Invention

[0007] The present invention aims to solve the above problems and provides a backflow prevention ventilation system and method for vertical shaft raise drilling rig construction. The present invention not only significantly improves the inherent safety level in raise drilling rig construction, but also realizes intelligent coordination of ventilation and tunneling through a unique design that is efficient and prevents backflow, thus combining safety, efficiency and practicality.

[0008] The technical solution adopted by the present invention to solve the aforementioned problem is as follows: A backflow prevention ventilation system for vertical shaft raise drilling rig construction is applied to the platform inside the shaft at the junction of the vertical shaft and the tunnel, including a jet ventilation module, a ventilation conveying module, a monitoring and control module, and a backflow prevention protection module; The ejector ventilation module is used to generate a negative pressure zone to draw out polluted air from the working face and transport the polluted air to the vertical shaft; The ventilation delivery module is connected to the ejector ventilation module and the vertical shaft respectively, providing a channel for the delivery of polluted air, and its length is dynamically adjusted according to the depth of the vertical shaft; The monitoring and control module is electrically connected to the ejector ventilation module and the backflow prevention module, and is used to monitor the operating parameters of the ventilation system in real time and intelligently regulate the operation of each module. The backflow prevention module is installed on the ventilation and conveying module and is used to automatically block the backflow path of the polluted air when the airflow stagnates or reverses.

[0009] As a preferred embodiment, a further technical solution of the present invention is as follows: Furthermore, the ejector ventilation module includes at least one mine-use explosion-proof ejector fan and an adjustable ejector isolation device; the high-speed nozzle of the ejector fan is sealed and connected to the air inlet of the ventilation conveying module, and the ejector fan is equipped with an intelligent frequency conversion control system; the adjustable ejector isolation device is sealed and connected to the air inlet of the ejector fan, and at least one air collection pipe is connected to the adjustable ejector isolation device, the air collection pipe extending to the tunnel construction section for sucking up polluted air in the tunnel.

[0010] Furthermore, there are two air collection ducts, which extend to any construction section of the left and right tunnels connected to the shaft, respectively, to achieve synchronous extraction of polluted air from both tunnels; the duct fan is fixed to the platform inside the shaft, and the high-speed nozzle of the duct fan is sealed and connected to the air inlet of the ventilation and conveying module to inject polluted air into the shaft at high speed.

[0011] Furthermore, the ventilation and conveying module includes a rigid duct, with flexible ducts connected to both the upper and lower ends of the rigid duct; the flexible duct connected to the upper end of the rigid duct is connected to the air inlet of the ventilation and conveying module; the flexible duct connected to the lower end of the rigid duct is connected to the air outlet of the ventilation and conveying module; the upper end of the rigid duct, the flexible duct, and the air outlet are all placed in a vertical shaft; the polluted air is discharged into the vertical shaft through the air outlet; the rigid duct has a segmented and detachable structure, and the length of the rigid duct varies with the excavation depth of the vertical shaft.

[0012] Furthermore, the backflow prevention module includes a mechanical backflow preventer valve, which is installed at the connection between the lower end of the rigid duct and the flexible duct. The mechanical backflow preventer valve includes a valve plate that can swing in one direction and wind direction, wind speed and wind pressure sensors that are linked to the valve plate. The wind direction, wind speed and wind pressure sensors detect the airflow direction, wind speed and wind pressure. When a positive wind speed is detected, the valve plate is kept open. When the airflow is detected to be stagnant or reversed, the valve plate is driven to close and mechanically locked, thereby physically blocking the backflow path.

[0013] Furthermore, when the exhaust fan of the ejector ventilation module stops, the valve plate of the mechanical check valve automatically closes, achieving physical isolation between the internal working space and the external platform environment.

[0014] Furthermore, the monitoring and control module includes a sensor assembly and a control box; the control box is built into the adjustable ejector isolation device, and the sensor assembly includes a gas concentration sensor installed at the end of the air collection duct or the air inlet of the ventilation delivery module; the control box is equipped with a logic controller that receives the monitoring signals from the sensor assembly, controls the start-up, shutdown, and speed adjustment of the ejector ventilation module, and issues an audible and visual alarm when the operating parameters are abnormal.

[0015] Furthermore, the gas concentration sensor is a CO concentration sensor, and the control box is linked with the intelligent frequency conversion control system of the ejector ventilation module. Based on the real-time data fed back by the gas concentration sensor, the speed of the induced draft fan is automatically adjusted to achieve on-demand ventilation and energy-saving operation.

[0016] A backflow prevention ventilation method for a vertical shaft raise shaft drilling rig construction system includes the following steps: S1: System installation and commissioning, integrating the anti-backflow ventilation system into the well platform, installing the control box inside the adjustable ejector isolation device, completing the sealed connection of each module's pipelines and circuits, and commissioning the sensor components, control box, and mechanical backflow check valve to ensure that all components operate normally in conjunction. S2: Negative pressure suction and sludge transport. The induced draft fan of the ejector ventilation module is started, and a stable negative pressure zone is formed at the inlet of the ejector ventilation module by utilizing the fluid ejection effect. The sludge in the tunnel construction section is sucked out through the air collection duct, and at the same time, the sludge in the bottom of the shaft is sucked out through the lower end of the rigid air duct of the ventilation transport module. After the two sludge air streams merge, they are injected into the shaft at high speed through the ventilation transport module and discharged to the outside of the shaft. S3: Real-time monitoring and intelligent control. The monitoring and control module continuously collects data on wind pressure, wind speed and gas concentration through sensor components. The control box built into the adjustable ejector isolation device receives the monitoring data and automatically adjusts the speed of the induced draft fan to achieve ventilation as needed. If the monitored parameters exceed the preset threshold, an audible and visual alarm will be issued immediately. S4: Anti-backflow blocking. When the wind direction, wind speed and wind pressure sensors detect stagnant or reversed airflow, the actuator of the anti-backflow protection module immediately drives the mechanical backflow valve to close and lock, physically blocking the backflow path of the polluted air. When the induced draft fan stops, the valve automatically closes, realizing physical isolation between the internal working space and the external platform environment. S5: The system dynamically adapts to changes in the depth of the shaft excavation. By using flanges or quick clamps to assemble and disassemble the rigid duct sections of the ventilation delivery module, the overall length of the rigid duct is adjusted to achieve dynamic matching between the rigid duct and the shaft depth. This ensures that the ventilation delivery module is always adapted to the shaft depth, guaranteeing the effectiveness of stale air extraction and delivery.

[0017] The present invention, which adopts the above technical solution, has the following prominent features compared with the prior art: 1. This invention completely eliminates the backflow of polluted air by constructing a collaborative ventilation mode of "positive pressure supply, negative pressure collection, and intelligent control"; 2. Effectively ensures construction safety and improves the working environment; by generating directional and controllable strong negative pressure, it can directly extract polluted air containing harmful gases and high concentrations of dust from the source of the tunneling face, greatly reducing the risk of accumulation of flammable and explosive gases and dust hazards underground, and creating a safer and healthier working environment for construction personnel. 3. It achieves efficient and directional ventilation and pollutant control; the intake of the air collection duct is always close to the tunnel excavation face and the pollutants are discharged through the vertical shaft, thus forming a shorter and more direct path for the discharge of polluted air, which greatly reduces the diffusion of polluted air in the tunnel and improves the efficiency and targeting of smoke and dust removal. 4. The problem of backflow of polluted air has been fundamentally solved. The mechanical backflow preventer is the key innovation. It physically isolates the possibility of polluted air or external air flowing back into the work area from the upper part of the shaft, ensuring the singleness and reliability of the ventilation direction. 5. The system operates reliably and has a high degree of intelligent monitoring. It monitors ventilation effect and air quality in real time and continuously through wind direction, wind speed, wind pressure sensors and gas sensors, and displays the data centrally in the control box. This allows operators to keep track of the system's operating status at any time, promptly detect abnormalities such as insufficient air volume, excessive gas, or pipeline blockage, achieve early warning and precise control, and improve the system's automation level and operational reliability. 6. It has good economic benefits and promotion value, and its structure is relatively simple. Its core components are sturdy and durable. It is especially suitable for complex conditions such as deep wells and high gas. By effectively preventing accidents, ensuring construction continuity and improving work efficiency, it can reduce construction safety risks and overall costs. It has broad application prospects in vertical shaft and deep hole engineering in mining, water conservancy, transportation and other fields. In summary, this invention not only significantly improves the inherent safety level of raise boring machine construction, but also achieves intelligent coordination between ventilation and tunneling through a unique design that is efficient and prevents backflow. It is an innovation that combines safety, efficiency and practicality. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the main view structure of the present invention; Figure 2 This is a schematic diagram of the structure of the ejector ventilation module of the present invention; Figure 3 This is a schematic diagram of the ventilation and conveying module of the present invention; Figure 4 This is a schematic diagram of the mechanical backflow preventer valve of the present invention; In the diagram: 1. Shaft; 2. Jet ventilation module; 3. Ventilation conveying module; 4. Drainage fan; 5. Adjustable jet isolation device; 6. Air collection duct; 7. Intelligent frequency conversion control system; 8. Rigid duct; 9. Flexible duct; 10. Air inlet duct; 11. Air outlet duct; 12. Mechanical check valve; 13. Valve plate; 14. Wind direction, wind speed, and wind pressure sensor; 15. Left tunnel; 16. Right tunnel; 17. Shaft platform; 18. Rigid duct section. Detailed Implementation

[0019] The following description of the embodiments will help the public better understand the present invention. However, the specific embodiments provided by the applicant should not and should not be regarded as a limitation on the technical solution of the present invention. Any changes to the definition of components or technical features and / or formal but not substantive changes to the overall structure should be regarded as the scope of protection defined by the technical solution of the present invention.

[0020] Compared to the problem of insufficient ventilation efficiency in ordinary ventilation systems, a more prominent and dangerous technical challenge in raise boring machine (PMM) operations is "sewage backflow." This phenomenon is highly likely to occur in complex construction environments, and existing measures are insufficient to effectively prevent it. Specific scenarios include: 1. When the ventilation system stops abnormally, the main ventilation fan stops operating due to power failure, equipment failure or maintenance. The original air pressure balance underground is broken. The polluted air (with different density and temperature than fresh air) accumulated in the upper part of the shaft or adjacent roadway will backflow to the working face under the action of gravity, thermal pressure or natural wind pressure, directly threatening the life safety of the workers. 2. When multiple working faces are intersecting, the shaft construction is often carried out simultaneously with the excavation of other roadways. The airflow of different ventilation systems interferes with each other, which can easily lead to the polluted air of one system being drawn into the fresh airflow of another system, causing secondary pollution. 3. When natural wind pressure has a significant impact, in deep wells, inclined wells with large elevation differences, or areas with drastic temperature changes, seasonal natural wind pressure can overcome the mechanical ventilation power, causing airflow to reverse and triggering backflow of polluted air; 4. In the instant after blasting, high-temperature and high-pressure blasting gas rushes out instantly, which will cause local airflow turbulence, briefly reverse the airflow direction, and form instantaneous backflow of polluted air.

[0021] Therefore, in order to solve the above-mentioned technical problems, the technical solution of the present invention is as follows: See Figures 1 to 3 As shown, a backflow prevention ventilation system for vertical shaft raise drilling rig construction is applied to the platform 17 inside the shaft 1 where the vertical shaft 1 and the tunnel meet. It includes a jet ventilation module 2, a ventilation conveying module 3, a monitoring and control module, and a backflow prevention module. The four modules work together to achieve efficient discharge of polluted air and effective blocking of polluted air backflow, adapting to the dynamic needs of raise drilling rig construction.

[0022] The ejector ventilation module 2 is used to generate a negative pressure zone to draw out polluted air from the working face and transport the polluted air to the shaft 1. The ejector ventilation module 2 includes at least one mine explosion-proof induced draft fan 4 and an adjustable ejector isolation device 5. The high-speed nozzle of the induced draft fan 4 is sealed and connected to the inlet of the ventilation conveying module 3. The induced draft fan 4 is equipped with an intelligent frequency conversion control system 7, which can flexibly adjust the speed according to the working conditions. The adjustable ejector isolation device 5 is sealed and connected to the air inlet of the induced draft fan 4 through a flexible connecting pipe, which plays the role of isolating and stabilizing the airflow. At least one air collection pipe 6 is connected to the adjustable ejector isolation device 5. The air collection pipe 6 extends to the tunnel construction section, which can accurately draw out polluted air in the tunnel and ensure that pollutants are captured at the source.

[0023] There are two air collection ducts 6, which extend to any construction section of the left tunnel 15 and right tunnel 16 connected to the shaft 1, respectively, which can realize the synchronous extraction of polluted air from the two tunnels and improve ventilation efficiency. The duct fan 4 is fixed to the platform 17 inside the shaft, which is firmly installed and easy to maintain. The high-speed nozzle of the duct fan 4 is sealed and connected to the air inlet of the ventilation conveying module 3, which can shoot the collected polluted air into the shaft 1 at high speed and realize rapid discharge.

[0024] The ventilation delivery module 3 is connected to the ejector ventilation module 2 and the vertical shaft 1, providing a stable channel for the delivery of polluted air. Its length can be dynamically adjusted according to the depth of the vertical shaft 1. The ventilation delivery module 3 includes a rigid duct 8, which is made of high-strength, corrosion-resistant material, suitable for the harsh, humid, and dusty environment underground. Flexible ducts 9 are connected to both ends of the rigid duct 8. The flexible ducts 9 can compensate for installation deviations and equipment vibrations, preventing damage to the ducts due to rigid connections. The flexible duct 9 connected to the upper end of the rigid duct 8 is connected to the air inlet of the ventilation delivery module 3. An air inlet duct 10 is connected to the flexible duct 9 located at the upper end of the rigid duct 8. The air inlet duct 10 is sealed to the high-speed nozzle of the induced draft fan 4 to ensure airflow. No leakage; the flexible duct 9 connected to the lower end of the rigid duct 8 is connected to the air outlet of the ventilation conveying module 3. An air outlet duct 11 is connected to the flexible duct 9 located at the lower end of the rigid duct 8. The upper end of the rigid duct 8, the flexible duct 9 and the air outlet duct 11 are all placed in the vertical shaft 1. The polluted air input into the ventilation conveying module 3 by the duct fan 4 is discharged into the vertical shaft 1 through the air outlet duct 11. The rigid duct 8 is a segmented and detachable structure, which is composed of multiple rigid duct segments 18 connected in sequence. Adjacent rigid duct segments 18 are connected by flanges or quick clamps. The length of the rigid duct 8 can be flexibly adjusted according to the excavation depth of the vertical shaft 1 to ensure that the ventilation conveying module 3 is always adapted to the depth of the vertical shaft 1 and to ensure the ventilation effect.

[0025] See Figure 4As shown, the backflow prevention module is installed on the ventilation and conveying module 3 and is the core component for blocking the backflow of polluted air. It is used to automatically block the backflow path of polluted air when the airflow is stagnant or reversed. The backflow prevention module includes a mechanical check valve 12, which is installed at the connection between the lower end of the rigid air duct 8 and the flexible air duct 9. The mechanical check valve 12 includes a valve plate 13 that can swing in one direction, a wind direction, wind speed and wind pressure sensor 14 that is linked to the valve plate 13, and an actuator. The wind direction, wind speed and wind pressure sensor 14 detects the airflow direction, wind speed and wind pressure. When a positive wind speed is detected, that is, polluted air flows towards the top of the shaft 1, the valve plate 13 is kept open to ensure smooth airflow. When the airflow is detected to be stagnant or reversed, that is, polluted air flows back towards the working face, the wind direction, wind speed and wind pressure sensor 14 sends a signal to the actuator, and the actuator immediately drives the valve plate 13 to close and mechanically lock, realizing the physical blockage of the backflow path. When the exhaust fan 4 of the ejector ventilation module 2 stops, the valve plate 13 of the mechanical backflow preventer valve 12 automatically closes, achieving physical isolation between the internal working space and the external platform environment, further ensuring operational safety.

[0026] The monitoring and control module is electrically connected to the ejector ventilation module 2 and the backflow prevention module. It is used to monitor the operating parameters of the ventilation system in real time and intelligently regulate the operation of each module. The monitoring and control module includes sensor components and a control box. The control box is built into the adjustable ejector isolation device 5, which saves installation space and facilitates protection, preventing dust and water vapor in the well from damaging electrical components. The sensor components include a gas concentration sensor installed at the end of the air collection duct 6 or the inlet of the ventilation delivery module 3. The gas concentration sensor is used to monitor the content of harmful gases in the polluted air and detect potential safety hazards in time. The control box is equipped with a logic controller, which can receive the monitoring signals from the sensor components, control the start, stop and speed adjustment of the ejector ventilation module 2 according to the monitoring data, and issue an audible and visual alarm when the operating parameters exceed the preset threshold to remind the staff to troubleshoot the fault in time.

[0027] The gas concentration sensor is a CO concentration sensor, which can accurately monitor carbon monoxide concentration and meet the safety requirements of mine construction. The control box is linked with the intelligent frequency conversion control system 7 of the ejector ventilation module 2. It automatically adjusts the speed of the induced draft fan 4 according to the real-time data fed back by the gas concentration sensor, so as to realize on-demand ventilation and energy-saving operation, and reduce energy consumption while ensuring ventilation effect.

[0028] See Figures 1 to 4 As shown, a backflow prevention ventilation method for a vertical shaft raise boring machine construction system includes the following steps: S1: System installation and commissioning. Integrate the anti-backflow ventilation system into the well platform 17, install the control box inside the adjustable ejector isolation device 5, complete the sealed connection of the pipelines and circuits of each module, and debug the sensor components, control box and mechanical backflow valve 12 to ensure that the linkage of each component is normal, laying the foundation for subsequent ventilation operations. S2: Negative pressure suction and waste air transport. Start the induced draft fan 4 of the ejector ventilation module 2 to form a stable negative pressure zone at the inlet of the ejector ventilation module 2 by utilizing the fluid ejection effect; draw the polluted air from the tunnel construction section through the air collection pipe 6. The two polluted air streams from the left tunnel 15 and the right tunnel 16 merge and are then injected at high speed into the vertical shaft 1 through the ventilation transport module 3 and discharged to the outside of the vertical shaft 1, realizing the rapid and directional discharge of polluted air; S3: Real-time monitoring and intelligent control. The monitoring and control module continuously collects data on wind pressure, wind speed and gas concentration through sensor components. The control box built into the adjustable ejector isolation device 5 receives the monitoring data and automatically adjusts the speed of the induced draft fan 4 according to the data to achieve ventilation as needed. If the monitored parameters exceed the preset threshold, an audible and visual alarm will be issued immediately to ensure the safe and stable operation of the system. S4: Anti-backflow blocking. When the wind direction, wind speed and wind pressure sensor 14 detects that the airflow is stagnant or reversed, the actuator of the anti-backflow protection module immediately drives the mechanical check valve 12 valve plate 13 to close and lock, physically blocking the backflow path of the sewage air; when the induced draft fan 4 stops, the valve plate 13 automatically closes, realizing the physical isolation between the internal working space and the external platform environment, and preventing sewage air from flowing back in. S5: The system dynamically adapts to the increase or decrease in the excavation depth of the shaft 1. By disassembling and assembling the rigid duct section 18 of the ventilation and conveying module 3 using flanges or quick clamps, the overall length of the rigid duct 8 is adjusted to achieve dynamic matching between the rigid duct 8 and the depth of the shaft 1. This ensures that the ventilation and conveying module 3 is always adapted to the depth of the shaft 1, guaranteeing the effect of turbid air extraction and conveying.

[0029] Working Principle: This invention generates a stable negative pressure zone through the ejector ventilation module 2, achieving precise extraction of polluted air from the working face and tunnel. The ventilation and conveying module 3 provides an efficient conveying channel for polluted air and can dynamically adapt to the depth of the shaft 1. The monitoring and control module collects system operating parameters in real time and intelligently adjusts the speed of the induced draft fan 4 to achieve on-demand ventilation and safety warnings. The backflow prevention module automatically closes the valve plate 13 and mechanically locks it when the airflow is abnormal or the fan stops, physically blocking the backflow path of polluted air. The four modules work together to build a complete ventilation system of "negative pressure extraction - efficient conveying - intelligent control - backflow prevention", completely solving the technical problem of polluted air backflow in raised shaft drilling operations and ensuring construction safety and the working environment.

[0030] The beneficial technical effects of this invention are: 1. This invention completely eliminates the backflow of polluted air by constructing a collaborative ventilation mode of "positive pressure supply, negative pressure collection, and intelligent control"; 2. Effectively ensures construction safety and improves the working environment; by generating directional and controllable strong negative pressure, it can directly extract polluted air containing harmful gases and high concentrations of dust from the source of the tunneling face, greatly reducing the risk of accumulation of flammable and explosive gases and dust hazards underground, and creating a safer and healthier working environment for construction personnel. 3. It achieves efficient and directional ventilation and pollutant control; the intake of the air collection duct 6 is always close to the tunnel excavation face and discharges pollutants through the vertical shaft 1, thus forming a shorter and more direct path for the discharge of polluted air, which greatly reduces the diffusion of polluted air in the tunnel and improves the efficiency and targeting of smoke and dust removal. 4. The mechanical backflow check valve 12 is a key innovation that fundamentally solves the problem of polluted air backflow. It physically isolates the possibility of polluted air or external air flowing back into the work area from the upper part of the shaft 1, ensuring the singleness and reliability of the ventilation direction. 5. The system operates reliably and has a high degree of intelligent monitoring. It monitors ventilation effect and air quality in real time and continuously through wind direction, wind speed and wind pressure sensors 14 and gas sensors, and displays the data centrally in the control box. This allows operators to keep track of the system's operating status at any time, promptly detect abnormalities such as insufficient air volume, excessive gas or pipeline blockage, achieve early warning and precise control, and improve the system's automation level and operational reliability. 6. It has good economic benefits and promotion value, and its structure is relatively simple. Its core components are sturdy and durable. It is especially suitable for complex conditions such as deep wells and high gas. By effectively preventing accidents, ensuring construction continuity and improving work efficiency, it can reduce construction safety risks and overall costs. It has broad application prospects in vertical shaft and deep hole engineering in mining, water conservancy, transportation and other fields. In summary, the anti-backflow ventilation system for vertical shaft raise boring machine (HMM) construction of this invention, by integrating an ejector ventilation module, a ventilation delivery module, a monitoring and control module, and an anti-backflow protection module, achieves effective extraction and delivery of polluted air from the working face. This system is optimized for the dynamic and complex working conditions of HMM construction, enabling rapid and effective forced delivery of fresh air to the working face while timely and directional discharge of polluted air to the outside of the well. The real-time monitoring and intelligent control functions of the monitoring and control module ensure that the ventilation system always remains in optimal working condition. Especially when ventilation power is interrupted or airflow becomes turbulent, the anti-backflow protection module can automatically and quickly block the backflow path of polluted air, effectively preventing the deterioration of air quality at the working face, thereby improving the safety of the construction environment and construction efficiency.

[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes made based on the description and drawings of the present invention are included within the scope of the present invention.

Claims

1. A backflow prevention ventilation system for vertical shaft raise boring machine construction, characterized in that: An in-shaft platform used at the intersection of a vertical shaft and a tunnel includes a jet ventilation module, a ventilation conveying module, a monitoring and control module, and a backflow prevention module. The ejector ventilation module is used to generate a negative pressure zone to draw out polluted air from the working face and transport the polluted air to the vertical shaft; The ventilation delivery module is connected to the ejector ventilation module and the vertical shaft respectively, providing a channel for the delivery of polluted air, and its length is dynamically adjusted according to the depth of the vertical shaft; The monitoring and control module is electrically connected to the ejector ventilation module and the backflow prevention module, and is used to monitor the operating parameters of the ventilation system in real time and intelligently regulate the operation of each module. The backflow prevention module is installed on the ventilation and conveying module and is used to automatically block the backflow path of the polluted air when the airflow stagnates or reverses.

2. The anti-backflow ventilation system for vertical shaft raise boring machine construction according to claim 1, characterized in that: The ejector ventilation module includes at least one mine-use explosion-proof ejector fan and an adjustable ejector isolation device; the high-speed nozzle of the ejector fan is sealed and connected to the air inlet of the ventilation conveying module, and the ejector fan is equipped with an intelligent frequency conversion control system; the adjustable ejector isolation device is sealed and connected to the air inlet of the ejector fan, and at least one air collection pipe is connected to the adjustable ejector isolation device, the air collection pipe extending to the tunnel construction section for sucking up polluted air in the tunnel.

3. The anti-backflow ventilation system for vertical shaft raise boring machine construction according to claim 2, characterized in that: The number of air collection ducts is two, which extend to any construction section of the left and right tunnels connected to the vertical shaft, respectively, to achieve synchronous extraction of polluted air from the two tunnels; the duct fan is fixed to the platform inside the shaft, and the high-speed nozzle of the duct fan is sealed and connected to the air inlet of the ventilation and conveying module to inject polluted air into the vertical shaft at high speed.

4. The anti-backflow ventilation system for vertical shaft raise boring machine construction according to claim 1 or 2, characterized in that: The ventilation and conveying module includes a rigid duct, with flexible ducts connected to both ends of the rigid duct. The flexible duct connected to the upper end of the rigid duct is connected to the air inlet of the ventilation and conveying module. The flexible duct connected to the lower end of the rigid duct is connected to the air outlet of the ventilation and conveying module. The upper end of the rigid duct, the flexible duct, and the air outlet are all placed in a vertical shaft. The polluted air is discharged into the vertical shaft through the air outlet. The rigid duct has a segmented and detachable structure, and the length of the rigid duct varies with the excavation depth of the vertical shaft.

5. The anti-backflow ventilation system for vertical shaft raise boring machine construction according to claim 4, characterized in that: The backflow prevention module includes a mechanical backflow preventer valve, which is installed at the connection between the lower end of the rigid duct and the flexible duct. The valve includes a valve plate that can swing in one direction and wind direction, wind speed and wind pressure sensors that are linked to the valve plate. The wind direction, wind speed and wind pressure sensors detect the airflow direction, wind speed and wind pressure. When a positive wind speed is detected, the valve plate is kept open. When the airflow is detected to be stagnant or reversed, the valve plate is driven to close and mechanically locked, thereby physically blocking the backflow path.

6. The anti-backflow ventilation system for vertical shaft raise boring machine construction according to claim 5, characterized in that: When the exhaust fan of the ejector ventilation module stops, the valve plate of the mechanical backflow preventer automatically closes, achieving physical isolation between the internal working space and the external platform environment.

7. The anti-backflow ventilation system for vertical shaft raise boring machine construction according to claim 2, characterized in that: The monitoring and control module includes a sensor assembly and a control box; the control box is built into the adjustable ejector isolation device, and the sensor assembly includes a gas concentration sensor installed at the end of the air collection duct or the air inlet of the ventilation delivery module; the control box is equipped with a logic controller, which receives the monitoring signals from the sensor assembly, controls the start-up, shutdown, and speed adjustment of the ejector ventilation module, and issues an audible and visual alarm when the operating parameters are abnormal.

8. The anti-backflow ventilation system for vertical shaft raise boring machine construction according to claim 7, characterized in that: The gas concentration sensor is a CO concentration sensor. The control box is linked with the intelligent frequency conversion control system of the ejector ventilation module. Based on the real-time data fed back by the gas concentration sensor, the speed of the induced draft fan is automatically adjusted to achieve on-demand ventilation and energy-saving operation.

9. A method for preventing backflow ventilation in a vertical shaft raise boring machine system according to claim 1, characterized in that: Includes the following steps: S1: System installation and commissioning, integrating the anti-backflow ventilation system into the well platform, installing the control box inside the adjustable ejector isolation device, completing the sealed connection of each module's pipelines and circuits, and commissioning the sensor components, control box, and mechanical backflow check valve to ensure that all components operate normally in conjunction. S2: Negative pressure suction and sludge transport. The induced draft fan of the ejector ventilation module is started, and a stable negative pressure zone is formed at the inlet of the ejector ventilation module by utilizing the fluid ejection effect. The sludge in the tunnel construction section is sucked out through the air collection duct, and at the same time, the sludge in the bottom of the shaft is sucked out through the lower end of the rigid air duct of the ventilation transport module. After the two sludge air streams merge, they are injected into the shaft at high speed through the ventilation transport module and discharged to the outside of the shaft. S3: Real-time monitoring and intelligent control. The monitoring and control module continuously collects data on wind pressure, wind speed and gas concentration through sensor components. The control box built into the adjustable ejector isolation device receives the monitoring data and automatically adjusts the speed of the induced draft fan to achieve ventilation as needed. If the monitored parameters exceed the preset threshold, an audible and visual alarm will be issued immediately. S4: Anti-backflow blocking. When the wind direction, wind speed and wind pressure sensors detect stagnant or reversed airflow, the actuator of the anti-backflow protection module immediately drives the mechanical backflow valve to close and lock, physically blocking the backflow path of the polluted air. When the induced draft fan stops, the valve automatically closes, realizing physical isolation between the internal working space and the external platform environment. S5: The system dynamically adapts to changes in the depth of the shaft excavation. By using flanges or quick clamps to assemble and disassemble the rigid duct sections of the ventilation delivery module, the overall length of the rigid duct is adjusted to achieve dynamic matching between the rigid duct and the shaft depth. This ensures that the ventilation delivery module is always adapted to the shaft depth, guaranteeing the effectiveness of stale air extraction and delivery.

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