Underground roadway pneumatic injection method and system

Abstract

The invention provides an underground roadway pneumatic ejection method and system, and the method comprises the steps that fresh air is conveyed to a driving working face of an underground roadway in a long-pressure mode, under the action of a fresh air press-in type fan, the fresh air is conveyed to the driving working face of the underground roadway through a fresh air duct, and the driving working face of the underground roadway is ejected through the fresh air duct; one end of the fresh air duct is located in the underground roadway and extends towards a driving working face, and the other end of the fresh air duct is located at the position, where a fresh air press-in type fan is located, outside the roadway; dust-containing airflow in a roadway is pumped out in a short pumping mode, and the dust-containing airflow is pumped out through a dust pumping air duct and a pneumatic ejection device arranged in the dust pumping air duct and close to a dust pumping inlet. By means of the dust control device, the problems that in traditional long-pressure short-suction dust control, installation and movement are inconvenient due to the fact that a negative-pressure air pipe is adopted, and the dust suction capacity and efficiency are reduced can be solved.

Description

[0001] Priority declaration

[0002] This application claims the priority of the Chinese application with application number: 2024108017729, filed on June 20, 2024, and patent name: A process method for long pressure and short extraction in underground coal mines, which is incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of dust control for mining excavation, and more specifically, to a method and system for pneumatic injection in underground tunnels. Background Art

[0004] In the production process of underground tunnel excavation, dust is the main safety hazard in coal mines and has always plagued the safety and health of miners.

[0005] In order to effectively control dust diffusion and improve the working environment of underground tunnel excavation, the traditional long-pressure and short-extraction method is currently used for dust control. Figure 1 The layout of the traditional long-pressure short-extraction dust control method is shown. The long-pressure part delivers fresh air to the excavation working face of the underground tunnel through the fresh air pressure-in fan 3 and the fresh air duct 1. The short-extraction part extracts the dust-containing airflow in the tunnel through the dust extraction duct 2 and the exhaust fan 20 arranged at the end of the dust extraction duct 2 away from the excavation working face. This traditional long-pressure short-extraction layout has the following problems:

[0006] (1) In underground tunnels, based on the accommodation space of the excavation area, the impact of dust on the fan, explosion-proof requirements, etc., the exhaust fan 20 can only be set at one end of the dust extraction duct 2 away from the excavation working face, and the exhaust fan 20 provides driving force for the dust extraction duct 2. The fresh air and the dust and / or gas in the tunnel form a dust-containing airflow in the dust extraction duct 2 as a high-speed negative pressure airflow, and under the drive of the exhaust fan 20, the dust-containing airflow is sucked into the dust extraction duct 2 for dust extraction, that is, the dust extraction duct 2 transmits the negative pressure airflow to the dust extraction port; that is, due to the setting position of the exhaust fan 20, the entire pipeline of the dust extraction duct 2 is a negative pressure area, and the dust extraction duct 2 adopts a negative pressure duct. The negative pressure duct has high rigidity requirements and needs to be made of steel or skeleton-type ducts. Such negative pressure ducts are heavy and inconvenient to install, move, turn and bend;

[0007] (2) In the traditional long-pressure and short-extraction dust control method, the dust extraction fan 2 is under negative pressure. Compared with positive pressure transportation, negative pressure transportation has lower transportation efficiency under the same power.

[0008] (3) During use, the pressure in the dust extraction duct 2 is lower than the surrounding atmospheric pressure, which is negative pressure. Negative pressure can cause the dust extraction duct 2 to deform, resulting in a smaller flow rate and a reduced dust collection capacity;

[0009] (4) The use of negative pressure air ducts can easily cause the dust extraction air cylinder 2 to age or break, resulting in air leakage, further affecting the dust collection efficiency.

[0010] Therefore, in order to solve the above problems, it is necessary to propose a method and system for pneumatic ejection in underground tunnels. Summary of the invention

[0011] In view of the above problems, the purpose of the present invention is to provide a method and system for pneumatic injection in underground tunnels to solve the problems of inconvenient installation and movement of negative pressure air ducts, reduced dust suction capacity and efficiency in traditional long-pressure and short-extraction dust control.

[0012] The present invention provides a method for pneumatic ejection in an underground tunnel, comprising:

[0013] The fresh air is delivered to the excavation working face of the underground tunnel by long pressure, wherein, under the action of the fresh air pressure-in blower, the fresh air is delivered to the excavation working face of the underground tunnel through the fresh air duct, one end of the fresh air duct is located in the underground tunnel and extends to the excavation working face, and the other end is located at the location of the fresh air pressure-in blower outside the tunnel;

[0014] The dust-laden airflow in the tunnel is extracted by a short extraction method, wherein the dust-laden airflow is extracted by a dust extraction duct and a pneumatic ejection device arranged in the dust extraction duct near a dust extraction inlet.

[0015] Preferably, the end of the dust extraction fan close to the excavation working face is the dust extraction inlet, and the end away from the excavation working face is the dust extraction outlet; wherein,

[0016] The distance between the dust extraction outlet and the pneumatic ejection device is greater than the distance between the dust extraction inlet and the pneumatic ejection device.

[0017] Preferably, the end of the fresh air duct located in the underground tunnel and extending toward the excavation working face is the fresh air outlet, and the end of the fresh air duct located outside the tunnel where the fresh air pressure-type fan is located is the fresh air inlet; wherein,

[0018] The distance between the dust extraction inlet and the excavation working face is smaller than the distance between the fresh air outlet and the excavation working face.

[0019] Preferably, in the pipe of the dust extraction duct, the area from the dust extraction inlet to the pneumatic ejection device is a negative pressure area, and the area from the pneumatic ejection device to the dust extraction outlet is a positive pressure area.

[0020] Preferably, the air jet device sucks the dust-laden airflow in the underground tunnel and mixes it with compressed air to form a mixed fluid, and the mixed fluid is pressurized;

[0021] The pressurized mixed fluid is conveyed to the dust extraction fan connected to the pneumatic ejection device;

[0022] The mixed fluid with the dust-containing airflow is extracted to the dust extraction outlet through the dust extraction blower.

[0023] The present invention also provides a system for pneumatic injection in underground tunnels, comprising: a fresh air duct arranged in the underground tunnel and extending to the outside of the tunnel, a fresh air pressure-inlet fan arranged outside the tunnel, a dust extraction duct arranged in the underground tunnel, and a pneumatic injection device arranged on the dust extraction duct, wherein:

[0024] One end of the fresh air duct extends along the underground tunnel toward the excavation working face, and the other end of the fresh air duct is located at the location of the fresh air pressure-in fan outside the tunnel, wherein the fresh air pressure-in fan transports fresh air to the excavation working face through the fresh air duct;

[0025] The pneumatic ejection device is arranged in the dust extraction cylinder near the dust extraction inlet.

[0026] Preferably, the end of the dust extraction fan close to the excavation working face is a dust extraction inlet, and the end away from the excavation working face is a dust extraction outlet; wherein,

[0027] The distance between the dust extraction outlet and the pneumatic ejection device is greater than the distance between the dust extraction inlet and the pneumatic ejection device.

[0028] Preferably, the end of the fresh air duct located in the underground tunnel and extending toward the excavation working face is the fresh air outlet, and the end of the fresh air duct located outside the tunnel where the fresh air pressure-type fan is located is the fresh air inlet; wherein,

[0029] The distance between the dust extraction inlet and the excavation working face is smaller than the distance between the fresh air outlet and the excavation working face.

[0030] Preferably, the dust extraction fan comprises a positive pressure zone and a negative pressure zone, wherein the positive pressure zone adopts a positive pressure air duct, and the negative pressure zone adopts a negative pressure air duct.

[0031] Preferably, the pneumatic ejection device comprises a high-pressure chamber, a mixing chamber connected to the high-pressure chamber, a contraction tube and a diffusion tube connected to the mixing chamber, and a pressure-expanding tube connected to the diffusion tube, a compressed air inlet is provided on one side of the high-pressure chamber, and the contraction tube is connected to the fluid inlet; wherein,

[0032] The high pressure chamber is used to store the compressed air input through the compressed air inlet and convey the compressed air into the mixing chamber;

[0033] The mixing chamber is used to mix the compressed air with the dust-containing airflow sucked in through the fluid inlet and the contraction tube to form a mixed fluid;

[0034] The diffusion tube is used to further mix the mixed fluid;

[0035] The diffuser is used to diffuse the mixed fluid that has been further mixed through the diffuser, so as to convert the kinetic energy of the mixed fluid into pressure energy.

[0036] Preferably, the compressed air stored in the high-pressure chamber is a high-pressure airflow, the mixed fluid in the mixing chamber is a low-pressure airflow, and the mixing chamber is a negative pressure area;

[0037] The pressure of the mixed fluid in the diffuser is higher than the pressure in the mixing chamber and lower than the pressure of the compressed air, and the diffuser is a positive pressure zone.

[0038] It can be seen from the above technical solutions that the method and system for pneumatic ejection in underground tunnels provided by the present invention have the following beneficial effects compared with the prior art:

[0039] (1) The dust extraction fan of the present invention is light in weight, easy to install and move, and not prone to aging or damage, thereby solving the problem that the traditional negative pressure fan is prone to aging or damage, resulting in air leakage and affecting the dust collection efficiency.

[0040] (2) The pneumatic ejection device of the present invention is arranged at a portion close to the dust extraction inlet. This arrangement makes the positive pressure area within the entire length of the dust extraction duct larger than the negative pressure area, and the conveying is mainly positive pressure conveying, thereby further increasing the dust suction capacity.

[0041] (3) The present invention inputs fresh air into the excavation working face through a fresh air pressure-injection fan and a fresh air duct. The fresh air and the dust-containing airflow generated by the excavation working face are sucked into the pneumatic injection device. The pneumatic injection device fully mixes the dust-containing airflow with compressed air, so that the dust can be effectively controlled and transported under the action of the airflow, which can not only improve the dust collection efficiency, but also reduce the impact of dust on the working environment.

[0042] (4) The present invention can realize long-term continuous dust control in the working area. The continuous injection of the pneumatic injection device can effectively reduce the dust concentration in the working area. The pneumatic injection device is combined with the air guide tube, the auxiliary dust reduction device and the tail dust reduction device to make the total dust reduction efficiency and the respirable dust reduction efficiency not less than 95% and 90%. In addition, it can effectively improve the safety and production efficiency of mines, change the working environment of the excavation tunnel, reduce the risk of miners getting sick due to long-term exposure to dust, and effectively prevent and reduce the occurrence of safety accidents.

[0043] In order to achieve the above and related purposes, one or more aspects of the present invention include the features that will be described in detail later. The following description and the accompanying drawings describe some exemplary aspects of the present invention in detail. However, these aspects indicate only some of the various ways in which the principles of the present invention can be used. In addition, the present invention is intended to include all these aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] By referring to the following description in conjunction with the accompanying drawings, and with a more comprehensive understanding of the present invention, other objects and results of the present invention will become more apparent and easy to understand. In the accompanying drawings:

[0045] Figure 1 This is a schematic diagram of the layout of the traditional long-pressure and short-extraction dust control method;

[0046] Figure 2 A schematic diagram of the layout of a method for pneumatic jetting in an underground tunnel according to an embodiment of the present invention;

[0047] Figure 3 A schematic diagram of a system for pneumatic jetting in underground tunnels according to an embodiment of the present invention;

[0048] Figure 4 A schematic diagram of the arrangement of detection instruments for a system for pneumatic jetting in an underground tunnel according to an embodiment of the present invention;

[0049] Figure 5 A schematic diagram of a dust control and dust reduction device for an underground tunnel pneumatic injection system according to an embodiment of the present invention;

[0050] Figure 6 A schematic diagram of the structure of a pneumatic ejection device according to an embodiment of the present invention;

[0051] Figure 7 , Figure 8 They are schematic diagrams of the locations of the pneumatic ejection devices according to embodiments of the present invention.

[0052] Reference numerals include:

[0053] 1. Fresh air duct; 2. Dust extraction duct; 3. Fresh air forced-in fan; 4. Pneumatic injection device; 5. Air guide duct; 6. Excavation working face; 7. Tail dust suppression device; 8. Methane concentration sensor I; 9. Methane concentration sensor II; 10. First dust concentration sensor; 11. Second dust concentration sensor; 12. Temperature and humidity sensor; 13. Dust suppression device I; 14. Dust suppression device II; 15. Sewage discharge port; 16. Regulating valve; 17. Gas backwash filter; 18. Ball valve; 19. Liquid backwash filter; 20. Exhaust fan; 21. Negative pressure zone; 22. Positive pressure zone; 41. High-pressure chamber; 42. Contraction tube; 43. Compressed air inlet; 44. Mixing chamber; 45. Diffuser; 46. Diffuser.

[0054] The same reference numerals throughout the drawings indicate similar or corresponding features or functions. DETAILED DESCRIPTION

[0055] In the following description, for the purpose of illustration, in order to provide a comprehensive understanding of one or more embodiments, many specific details are set forth. However, it is apparent that these embodiments may also be implemented without these specific details. In other examples, for ease of describing one or more embodiments, well-known structures and devices are shown in the form of block diagrams.

[0056] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0057] It should be noted that the structural names "fresh air duct", "dust extraction duct" and "pneumatic injection device" in the technical solution of the present invention are respectively equivalent to the "fresh air positive pressure flexible duct", "dust control positive pressure flexible duct" and "gas injection dust control device" in the priority application, and this is hereby explained.

[0058] In view of the problems in the above-mentioned traditional long-pressure and short-extraction dust control, such as the inconvenient installation and movement of the negative pressure air duct, and the reduced dust suction capacity and efficiency, the present invention provides a method and system for pneumatic ejection in underground tunnels.

[0059] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0060] Figure 2 , Figure 7 and Figure 8 The method of pneumatic ejection in an underground tunnel provided by the present invention is shown in combination with each other. The method of pneumatic ejection in an underground tunnel provided by the present invention comprises:

[0061] S1: fresh air is delivered to the excavation working face of the underground tunnel by long pressure, wherein, under the action of a fresh air pressure-in blower, the fresh air is delivered to the excavation working face of the underground tunnel through a fresh air duct, one end of the fresh air duct is located in the underground tunnel and extends to the excavation working face, and the other end is located at the location of the fresh air pressure-in blower outside the tunnel;

[0062] S2: The dust-laden airflow in the tunnel is extracted by a short extraction method, wherein the dust-laden airflow is extracted by a dust extraction duct and a pneumatic ejection device disposed in the dust extraction duct near a dust extraction inlet.

[0063] In the embodiment of the present invention, fresh air is input into the excavation working face 6 through the fresh air pressure-in fan 3 and the fresh air duct 1. The fresh air and the dust and gas generated by the excavation working face 6 form a dust-containing airflow, which is sucked into the pneumatic injection device 4. The pneumatic injection device 4 fully mixes the dust-containing airflow with compressed air, so that the dust can be effectively controlled and transported under the action of the airflow, which can not only improve the dust collection efficiency, but also reduce the impact of dust on the working environment.

[0064] In the embodiment of the present invention, in order to improve the dust collection efficiency and control the dust in the working area for a long time, a pneumatic ejector device 4 is used. The pneumatic ejector device 4 is powered by external high-pressure gas, and the fresh air, dust and gas continuously sucked into the underground tunnel are effectively transported to the dust extraction outlet under the action of the power, thereby not only improving the dust collection efficiency, but also realizing the long-term continuous dust control in the working area, effectively reducing the dust concentration in the working area, and keeping the working environment clean and safe.

[0065] Specifically, the end of the fresh air duct 1 located in the underground tunnel and extending to the excavation working face 6 is the fresh air outlet, and the end of the fresh air duct 1 located outside the tunnel where the fresh air pressure-type fan 3 is located is the fresh air inlet; the end of the dust extraction duct 2 close to the excavation working face 6 is the dust extraction inlet, and the end away from the excavation working face 6 is the dust extraction outlet; wherein the distance between the dust extraction inlet and the excavation working face 6 is smaller than the distance between the fresh air outlet and the excavation working face 6. That is: the distance between the dust extraction inlet and the excavation working face 6 is Ld, and the distance between the fresh air outlet and the excavation working face 6 is Lc, then Lc>Ld. Figure 3As shown, fresh air is transported to the excavation working face 6 along the fresh air flow direction through the fresh air duct 1, and the fresh air forms a mixed fluid with the dust and / or gas in the excavation tunnel. The mixed fluid is transported to the dust extraction outlet along the positive pressure air flow direction along the dust extraction duct 2. The preset distance between the dust extraction inlet and the excavation working face 6 is less than or equal to 5m, and the preset distance between the fresh air outlet and the excavation working face 6 is greater than the preset distance between the dust extraction inlet and the excavation working face 6. In specific applications, the preset distance is determined according to actual conditions and is not limited to the above-defined distance.

[0066] exist Figure 7 and Figure 8 In the illustrated embodiment, it is clearly shown that the pneumatic ejection device 4 is located at different positions of the dust extraction cylinder 2. The pneumatic ejection device 4 is arranged in the dust extraction cylinder 2 near the dust extraction inlet, wherein the distance between the dust extraction outlet and the pneumatic ejection device 4 is greater than the distance between the dust extraction inlet and the pneumatic ejection device 4.

[0067] like Figure 7 As shown, the pneumatic ejector 4 is arranged at the end of the dust extraction inlet of the dust extraction duct 2. The pneumatic ejector 4 inhales dust-containing airflow (the fluid formed by the fresh air and dust in the tunnel, or the fluid formed by the fresh air, dust and gas in the coal mine tunnel, collectively referred to as: dust-containing airflow), and forms a mixed fluid after processing the dust-containing airflow and compressed air. The mixed fluid is input into the dust extraction duct 2. The mixed fluid in the dust extraction duct 2 is a positive pressure area, so that the mixed fluid is effectively controlled and transported in the dust extraction duct 2. In other words, the mixed fluid discharged from the pneumatic ejector 4 is a positive pressure fluid. When the pneumatic ejector 4 is at the end of the dust extraction inlet of the dust extraction duct 2, the mixed fluid in the internal pipe of the dust extraction duct 2 is a positive pressure, that is, the internal pipe of the entire dust extraction duct 2 is a positive pressure area.

[0068] like Figure 8 As shown, the position where the pneumatic ejector 4 is arranged in the dust extraction duct 2 is: the distance between the pneumatic ejector 4 and the dust extraction outlet is L1, and the distance between the dust extraction inlet and the pneumatic ejector 4 is L2, then L2<L1, that is: the pneumatic ejector 4 is arranged in the area close to the dust extraction inlet of the dust extraction duct 2, that is to say, the position where the pneumatic ejector 4 is arranged can be set as needed, as long as the positive pressure area in the dust extraction duct 2 is ensured to be greater than the negative pressure area.

[0069] exist Figure 8In the embodiment shown, the dust extraction duct 2 includes a positive pressure area 22 and a negative pressure area 21. In the duct of the dust extraction duct 2, the distance L2 from the dust extraction inlet to the pneumatic ejection device 4 is the negative pressure area 21, and the distance L1 from the pneumatic ejection device 4 to the dust extraction outlet is the positive pressure area 22. To ensure that the positive pressure area is greater than the negative pressure area, it is sufficient to ensure that L2 < L1. Among them, the area from the dust extraction inlet to the pneumatic ejection device 4 is the negative pressure area 21 of the dust extraction duct (the distance of this part is L2), and the airflow at this time is a negative pressure airflow; the area from the dust extraction outlet to the pneumatic ejection device 4 is the positive pressure area 22 (the distance of this part is L1), and the airflow in this part is a mixed fluid discharged from the pneumatic ejection device 4, and the airflow in this part is a positive pressure airflow. Therefore, the pneumatic ejector device 4 uses compressed air as a power source to absorb the dust-containing airflow formed by the excavation working face 6 for processing. The airflow processed by the pneumatic ejector device 4 is a mixed airflow, which is discharged to the positive pressure area of ​​the dust extraction duct 2, thereby achieving dust capture at the dust source and safe and efficient dust reduction.

[0070] In step S2, the dust-containing airflow in the underground tunnel is sucked by the pneumatic ejection device 4 to mix with compressed air to form a mixed fluid, and the mixed fluid is pressurized; the pressurized mixed fluid is transported to the dust extraction cylinder 2 connected to the pneumatic ejection device 4; the mixed fluid with the dust-containing airflow is extracted to the dust extraction outlet through the dust extraction cylinder 2.

[0071] In order to further improve the dust capture and transportation capabilities, the present invention also pushes the dust in the tunnel to the center of the wind flow through the wall-attached wind control method, thereby realizing the centralized control and transportation of dust. Specifically, by controlling a specific wind flow, the wind flow forms a wall-attached effect in the working area, so that the wind flow can flow along the coal wall or the tunnel wall, pushing the dust in the tunnel to the center of the wind flow, thereby realizing the centralized control and transportation of dust, which not only improves the dust carrying capacity of the wind flow, but also reduces the disturbance of the wind flow to the working area.

[0072] In addition, for realizing the above-mentioned method of pneumatic ejection in underground tunnels, the present invention also provides a system for pneumatic ejection in underground tunnels. Figures 3 to 8 The dust control system of pneumatic injection in underground tunnels is illustrated from different angles.

[0073] like Figures 3 to 8As shown together, the dust control system of pneumatic injection in the underground tunnel provided by the present invention includes: a fresh air duct 1 arranged in the underground tunnel and extending to the outside of the tunnel, a fresh air pressure-type fan 3 arranged outside the tunnel, a dust extraction duct 2 arranged in the underground tunnel, and a pneumatic injection device 4 arranged on the dust extraction duct 2, wherein one end of the fresh air duct 1 extends along the underground tunnel and toward the excavation working face 6, and the other end of the fresh air duct 1 is located at the location of the fresh air pressure-type fan 3 outside the tunnel, wherein the fresh air pressure-type fan 3 transports fresh air to the excavation working face 6 through the fresh air duct 1; the pneumatic injection device 4 is arranged in a portion close to the dust extraction inlet.

[0074] Among them, the end of the dust extraction duct 2 close to the excavation working face 6 is the dust extraction inlet, and the end away from the excavation working face 6 is the dust extraction outlet. The pneumatic injection device 4 is used to absorb the dust-containing airflow in the underground tunnel. The distance between the pneumatic injection device 4 and the dust extraction outlet is greater than the distance between the dust extraction inlet and the pneumatic injection device 4, that is: if the distance between the pneumatic injection device 4 and the dust extraction outlet is L1, and the distance between the dust extraction inlet and the pneumatic injection device 4 is L2, then L2<L1.

[0075] Among them, the end of the fresh air duct 1 located in the underground tunnel and extending to the excavation working face 6 is the fresh air outlet, and the end of the fresh air duct 1 located outside the tunnel where the fresh air pressure fan 3 is located is the fresh air inlet; wherein, the distance between the dust extraction inlet and the excavation working face 6 is smaller than the distance between the fresh air outlet and the excavation working face 6, that is, the distance between the dust extraction inlet and the excavation working face 6 is Ld, and the distance between the fresh air outlet and the excavation working face 6 is Lc, then Lc>Ld.

[0076] In the embodiment of the present invention, the pneumatic ejector device 4 can also be called an ejector, an ejector, etc. It is a vacuum obtaining device that uses fluid to transfer energy and mass, that is, a device that uses a working fluid with a certain pressure to eject a high-speed fluid through a nozzle, converts pressure energy into velocity energy, and reduces the pressure in the suction area to generate a vacuum. In the pneumatic ejector device 4, two fluids with different pressures mix with each other and exchange energy to form a mixed fluid. The mixed fluid is divided into a gas (steam) phase, a liquid phase, or a mixture of gas (steam), liquid and solid. Before entering the pneumatic ejector device 4, the medium with a higher pressure is called a working medium. In the embodiment of the present invention, compressed air is used as the working medium.

[0077] Among them, the working principle of the pneumatic ejector device 4 is: a high-speed jet is formed by accelerating the working medium (high-pressure gas); the high-speed jet generates a negative pressure area during the flow process, and the surrounding secondary fluid (air, dust, water, etc., among which, in the embodiment of the present invention, it is the dust-containing airflow formed by the fresh air, dust and gas in the underground tunnel) is sucked in and mixed to form a mixed fluid; the mixed fluid is decelerated by diffusion, and the kinetic energy is converted into pressure to realize the transportation of dust and gas.

[0078] In the embodiment of the present invention, the high-pressure gas is compressed air, the inhaled fluid is the dust-containing airflow in the underground tunnel, and the fluid expelled by pushing is a mixed fluid.

[0079] exist Figure 6 In the illustrated embodiment, the pneumatic ejection device 4 includes a high-pressure chamber 41, a mixing chamber 44 connected to the high-pressure chamber 41, a contraction tube 42 and a diffusion tube 45 connected to the mixing chamber 44, and a pressure diffuser 46 connected to the diffusion tube 45. A compressed air inlet 43 is provided on one side of the high-pressure chamber 41, and the contraction tube 42 is connected to the fluid inlet; wherein the high-pressure chamber 41 is used to store the compressed air input through the compressed air inlet 43 and inject the compressed air into the mixing chamber 44; the mixing chamber 44 is used to mix the compressed air with the dust-containing airflow sucked in through the fluid inlet and the contraction tube 42 to form a mixed fluid; the diffusion tube 45 is used to further mix the mixed fluid; the pressure diffuser 46 is used to diffuse the mixed fluid further mixed through the diffusion tube 45, and convert the kinetic energy of the mixed fluid into pressure energy.

[0080] The compressed air stored in the high-pressure chamber 41 is a high-pressure airflow, the mixed fluid in the mixing chamber 44 is a low-pressure airflow, and the mixing chamber 44 is a negative pressure zone; the pressure of the mixed fluid in the diffuser 46 is higher than the pressure in the mixing chamber 44 and lower than the pressure of the compressed air in the high-pressure chamber 41, and the diffuser 46 is a positive pressure zone. Figure 6 As shown, high-pressure gas is stored in the high-pressure chamber 41 and ejected into the mixing chamber 44; due to adiabatic expansion, the pressure energy in the high-pressure moving fluid is converted into kinetic energy, so that the flow rate increases but the pressure decreases. At this time, due to the pressure drop of the moving fluid, a negative pressure area will be formed in the mixing chamber 44; due to the existence of the negative pressure area, the mixing chamber 44 will inhale the dust-containing airflow and mix the inhaled dust-containing airflow with the moving fluid in the mixing chamber 44. The mixed fluid then enters the diffuser 45 and the diffuser 46, is fully mixed in the diffuser 45, and the kinetic energy is converted back into pressure energy; finally, the pressure of the mixed fluid generated by the diffuser 45 is higher than the pressure in the mixing chamber 44 and lower than the pressure of the compressed air in the high-pressure chamber 41.

[0081] like Figure 6 As shown, due to the suction of the negative pressure area, the fluid in the high pressure chamber 41 is ejected toward the mixing chamber 44. The arrow indicates the direction of the fluid. When the low pressure airflow containing dust begins to mix with the high pressure fluid in the mixing chamber 44, the mixed fluid passes through the diffuser 45 and enters the diffuser 46, the dynamic pressure decreases and the static pressure increases, and the kinetic energy is further increased and converted back into pressure energy.

[0082] In addition, the underground tunnel pneumatic injection dust control system provided by the present invention also includes an air guide tube 5, an auxiliary dust suppression device and a tail dust suppression device 7, such as Figure 3 As shown, an air guide duct 5 for multi-angle air outlet is provided at the end of the fresh air duct 1 close to the excavation working face 6. The same or different air outlets are provided on the air guide duct 5 to achieve 360° air outlet, so that the fresh air can be more evenly and slowly distributed in the tunnel, and the air guide duct 5 can reduce the wind speed to a certain extent, and the appropriate wind speed also has the effect of preventing dust.

[0083] In order to achieve multi-point dust control, the auxiliary dust suppression device is set in the middle area of ​​the dust extraction duct 2, and the tail dust suppression device 7 is set at the tail of the dust extraction duct 2. The auxiliary dust suppression device is set in appropriate number according to the actual situation. Figure 5 In the illustrated embodiment, the auxiliary dust suppression device comprises two groups of dust suppression devices, namely dust suppression device I 13 and dust suppression device II 14. The tail dust suppression device 7 is a spray dust suppression device, and a sewage discharge port 15 is provided at the rear of the spray dust suppression device.

[0084] The compressed air used by the pneumatic ejection device 4 is underground compressed air, and the water used by the tail dust suppression device 7 is underground water. Specifically, Figure 5 As shown, the underground compressed air sequentially passes through the regulating valve 16, the gas backwash filter 17, and the compressed air inlet 43 into the high-pressure chamber 41 of the pneumatic ejection device 4. The tail dust removal device 7 uses underground water, which sequentially passes through the ball valve 18 and the liquid backwash filter 19 into the tail dust removal device 7.

[0085] In an embodiment of the present invention, the fresh air duct 1 and the dust extraction duct 2 adopt coated cloth ducts. The dust extraction duct 2 includes a positive pressure zone 22 and a negative pressure zone 21, wherein the positive pressure zone 22 adopts a positive pressure duct, and the negative pressure zone 21 adopts a negative pressure duct, wherein the dust extraction duct may partially or completely adopt a telescopic air duct as required, and the telescopic air duct is controlled by a steel wire rope. In addition, in order to protect the pneumatic ejection device 4, a protective net is provided at the air inlet of the front dust suction port of the pneumatic ejection device 4, and the mesh aperture of the protective net is 30-150mm. In specific applications, the mesh aperture of the protective net is designed according to actual conditions.

[0086] In order to better monitor the dust and gas concentration underground, monitoring instruments are also installed in the tunnels. Each monitoring instrument is set at a suitable position according to the actual situation, such as Figure 4 As shown, a methane concentration sensor, a dust concentration sensor, a temperature and humidity sensor 12 and a wind speed sensor (not shown in the figure) are also provided in the tunnel. At least two methane concentration sensors are provided. In specific applications, the specific number is set according to the actual situation. Figure 5In the embodiment, there are two methane concentration sensors, namely, methane concentration sensor I8 and methane concentration sensor II9. The methane concentration sensor I8 is arranged at the dust generating area of ​​the tunneling working face 6, and the methane concentration sensor II9 is ​​arranged at the rear end of the tail dust suppression device 7. The number of dust concentration sensors is at least two. Figure 5 In the embodiment, there are two dust concentration sensors, namely: a first dust concentration sensor 10 and a second dust concentration sensor 11. The first dust concentration sensor 10 is set at a preset distance from the tunneling head (it can be set at the driver's position about 10m away from the tunneling head as needed), and the second dust concentration sensor 11 is set at a preset distance from the tunneling head (it can be set at the driver's rear position 15m away from the tunneling head as needed), and the two dust concentration sensors are 1.5m-2.0m away from the bottom plate of the tunneling head and not less than 0.5m away from the tunnel side. The temperature and humidity sensor 12 and the wind speed sensor are set at the preset positions according to the actual situation.

[0087] In the method and system provided by the present invention, the underground tunnels include coal tunnels, semi-coal-rock tunnels and rock tunnels with gas gushing out. The present invention can realize long-term continuous dust control in the working area. The continuous injection of the pneumatic injection device 4 can effectively reduce the dust concentration in the working area, and the pneumatic injection device 4 is combined with the air guide 5, the auxiliary dust reduction device and the tail dust reduction device 7 to make the total dust reduction efficiency and the respirable dust reduction efficiency not less than 95% and 90%, thereby effectively improving the safety and production efficiency of the mine, changing the working environment of the excavation tunnel, reducing the risk of long-term exposure of excavation miners to dust and illness, and effectively preventing and reducing the occurrence of safety accidents.

[0088] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A method for pneumatic jetting in underground tunnels, characterized in that: include: The fresh air is delivered to the excavation working face of the underground tunnel by long pressure, wherein, under the action of the fresh air pressure-in blower, the fresh air is delivered to the excavation working face of the underground tunnel through the fresh air duct, one end of the fresh air duct is located in the underground tunnel and extends to the excavation working face, and the other end is located at the location of the fresh air pressure-in blower outside the tunnel; The dust-laden airflow in the tunnel is extracted by a short extraction method, wherein the dust-laden airflow is extracted by a dust extraction duct and a pneumatic ejection device arranged in the dust extraction duct near a dust extraction inlet.

2. The method for pneumatic jetting in underground tunnels according to claim 1, characterized in that: The end of the dust extraction fan close to the excavation working face is the dust extraction inlet, and the end away from the excavation working face is the dust extraction outlet; wherein, The distance between the dust extraction outlet and the pneumatic ejection device is greater than the distance between the dust extraction inlet and the pneumatic ejection device.

3. The method for pneumatic jetting in underground tunnels according to claim 2, characterized in that: The end of the fresh air duct located in the underground tunnel and extending to the excavation working face is the fresh air outlet, and the end of the fresh air duct located outside the tunnel where the fresh air pressure-type fan is located is the fresh air inlet; wherein, The distance between the dust extraction inlet and the excavation working face is smaller than the distance between the fresh air outlet and the excavation working face.

4. The method for pneumatic jetting in underground tunnels according to claim 3, characterized in that: In the pipeline of the dust extraction duct, the area from the dust extraction inlet to the pneumatic ejection device is a negative pressure area, and the area from the pneumatic ejection device to the dust extraction outlet is a positive pressure area.

5. The method for pneumatic jetting in underground tunnels according to claim 4, characterized in that: The pneumatic ejection device sucks the dust-containing airflow in the underground tunnel and mixes it with compressed air to form a mixed fluid, and pressurizes the mixed fluid; The pressurized mixed fluid is conveyed to the dust extraction fan connected to the pneumatic ejection device; The mixed fluid with the dust-containing airflow is extracted to the dust extraction outlet through the dust extraction blower.

6. A system for pneumatic jetting in underground tunnels, characterized in that: include: A fresh air duct arranged in an underground tunnel and extending to the outside of the tunnel, a fresh air forced-in fan arranged outside the tunnel, a dust extraction duct arranged in the underground tunnel, and a pneumatic ejection device arranged on the dust extraction duct, wherein: One end of the fresh air duct extends along the underground tunnel toward the excavation working face, and the other end of the fresh air duct is located at the location of the fresh air pressure-in fan outside the tunnel, wherein the fresh air pressure-in fan transports fresh air to the excavation working face through the fresh air duct; The pneumatic ejection device is arranged in the dust extraction cylinder near the dust extraction inlet.

7. The system for pneumatic jetting in underground tunnels according to claim 6, characterized in that: The end of the dust extraction fan close to the excavation working face is a dust extraction inlet, and the end away from the excavation working face is a dust extraction outlet; wherein, The distance between the dust extraction outlet and the pneumatic ejection device is greater than the distance between the dust extraction inlet and the pneumatic ejection device.

8. The system for pneumatic jetting in underground tunnels according to claim 7, characterized in that: The end of the fresh air duct located in the underground tunnel and extending to the excavation working face is the fresh air outlet, and the end of the fresh air duct located outside the tunnel where the fresh air pressure-type fan is located is the fresh air inlet; wherein, The distance between the dust extraction inlet and the excavation working face is smaller than the distance between the fresh air outlet and the excavation working face.

9. The underground tunnel pneumatic ejection system according to claim 6, characterized in that: The dust extraction fan comprises a positive pressure zone and a negative pressure zone, wherein the positive pressure zone adopts a positive pressure air duct, and the negative pressure zone adopts a negative pressure air duct.

10. The underground tunnel pneumatic ejection system according to claim 6, characterized in that: The pneumatic ejection device comprises a high-pressure chamber, a mixing chamber connected to the high-pressure chamber, a contraction tube and a diffusion tube connected to the mixing chamber, and a pressure-expanding tube connected to the diffusion tube. A compressed air inlet is arranged on one side of the high-pressure chamber, and the contraction tube is connected to the fluid inlet; wherein, The high pressure chamber is used to store the compressed air input through the compressed air inlet and convey the compressed air into the mixing chamber; The mixing chamber is used to mix the compressed air with the dust-containing airflow sucked in through the fluid inlet and the contraction tube to form a mixed fluid; The diffusion tube is used to further mix the mixed fluid; The diffuser is used to diffuse the mixed fluid that has been further mixed through the diffuser, so as to convert the kinetic energy of the mixed fluid into pressure energy.

11. The underground tunnel pneumatic ejection system according to claim 10, characterized in that: The compressed air stored in the high-pressure chamber is a high-pressure airflow, the mixed fluid in the mixing chamber is a low-pressure airflow, and the mixing chamber is a negative pressure area; The pressure of the mixed fluid in the diffuser is higher than the pressure in the mixing chamber and lower than the pressure of the compressed air, and the diffuser is a positive pressure zone.

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