Coal mine energy-saving unpowered drainage device and method

Abstract

The invention discloses a coal mine energy-saving unpowered drainage device and method, and relates to the technical field of coal mine energy-saving equipment, the coal mine energy-saving unpowered drainage device is installed in a large-aperture drill hole with the diameter larger than or equal to 350 mm, the coal mine energy-saving unpowered drainage device comprises a large-aperture main pipe connected with the large-aperture drill hole in a sealed mode, and an air chamber is formed between the top wall of the large-aperture main pipe and a water layer of the large-aperture drill hole; the top of the large-aperture main pipe is communicated with an air inlet valve, a pressure release valve and a drainage pipe, the air inlet valve and the pressure release valve are respectively communicated with the air chamber, and the bottom end of the drainage pipe penetrates through the large-aperture main pipe and extends to a position at least 1m below the liquid level of a water layer of the large-aperture drill hole. The drainage system can drain water without power, is more energy-saving, has no electrical equipment intervention, is more reliable in safety, stable and efficient in drainage capacity, longer in service life and simple and convenient to maintain.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal mine energy-saving equipment, for example, to a coal mine energy-saving and power-free drainage device and method. BACKGROUND

[0002] In the process of coal mining, groundwater often seeps out, which brings safety hazards to mining operations. In order to effectively eliminate these hazards, protect miners and improve mining efficiency, drilling drainage operation is needed in coal mine underground. The traditional coal mine underground drainage generally uses electric centrifugal pumps, but there are the following technical defects.

[0003] High energy consumption: a single 55kW water pump consumes about 480,000 degrees per year, accounting for 15%-20% of the total power consumption of the coal mine.

[0004] Safety hazards: electrical equipment has explosion risk in gas environment. In the past five years, gas accidents caused by drainage systems accounted for 7.3% of the total number of coal mine accidents in China.

[0005] Maintenance difficulties: the pump impeller has a service life of less than 2000 hours in the gangue-containing water flow, and the replacement operation needs to stop production for 3-5 days. SUMMARY

[0006] In order to have a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not a general review, nor is it intended to determine the key / important components or to delineate the scope of protection of these embodiments, but as a prelude to the detailed description below.

[0007] In order to solve the above technical problems, the present application provides a coal mine energy-saving and power-free drainage device; the coal mine energy-saving and power-free drainage device can drain without power, is more energy-saving, has more reliable safety without electrical equipment intervention, has stable and efficient drainage capacity, has longer service life and is easy to maintain.

[0008] The coal mine energy-saving and power-free drainage device provided by the present application is installed in a large-diameter drill hole with a diameter of ≥350mm, and comprises a large-diameter main pipe in sealing connection with the large-diameter drill hole. An air chamber is formed between the top wall of the large-diameter main pipe and the water layer of the large-diameter drill hole. The top of the large-diameter main pipe is communicated with an air inlet valve, a pressure relief valve and a drainage pipe. The air inlet valve and the pressure relief valve are respectively communicated with the air chamber. The bottom end of the drainage pipe extends to at least 1m below the water surface of the water layer of the large-diameter drill hole through the large-diameter main pipe.

[0009] In a further improvement of the present application, the sealing connection of the large-diameter drill hole and the large-diameter main pipe adopts a three-stage composite sealing structure, which comprises, Primary sealing layer: at least 3 rubber water stop belts are circumferentially welded on the outer surface of the large-diameter main pipe wall, the cross section of the water stop belt is trapezoidal structure, and the Shore hardness of the water stop belt is 70±5; Secondary sealing layer: a rapid-setting cement slurry containing 12wt% magnesium oxide expander and 5wt% silica ash is injected into the gap between the large-aperture main pipe and the large-aperture borehole, with a water-cement ratio of 0.4:1; Final sealing layer: a polyurethane foaming layer with a closed cell rate of ≥90% is arranged outside the large-aperture borehole and the large-aperture main pipe port, with a density of 350±50kg / m3, a thickness of 50-80mm, and a thermal conductivity of ≤0.025W / (m·K).

[0010] In the further improvement of the application, the air chamber is provided with an arc-shaped flow guide plate, and the arc-shaped flow guide plate is uniformly provided with honeycomb-shaped air guide holes, and the opening rate of the honeycomb-shaped air guide holes is 35%-45%; the bottom of the arc-shaped flow guide plate is provided with an arc-shaped flow guide rib.

[0011] In the further improvement of the application, the pressure relief valve and the air inlet valve are electromagnetic valves.

[0012] In the further improvement of the application, the intelligent pressure regulating module is further included, and the pressure value of the air chamber is regulated in real time to fluctuate within a range of ±1.5% of a set value, and the response time is ≤0.8 seconds; the intelligent pressure regulating module comprises, The pressure closed-loop control system comprises an air compressor, a gas storage tank, an air inlet valve in communication with the gas storage tank, a piezoresistive sensor arranged in the air chamber, a pressure relief valve, and an STM32H743 processor; The fuzzy PID algorithm processor is a parameter self-tuning program realized in the STM32H743 processor, and the proportional coefficient Kp is dynamically adjusted according to the error absolute value |e|, the integral time Ti is 2-5s, and the differential time Td is 0.1-0.3s, wherein e is the pressure deviation; The air pressure prediction model is constructed based on an LSTM neural network, the input layer comprises 125 nodes including pressure values, flow rate change rates and historical 120-second pressure sequences, the hidden layer comprises 64 LSTM units, the output is a future 3-second pressure prediction value, and the training data set comprises 0.3-1.2MPa working condition data in a coal mine underground.

[0013] In the further improvement of the application, the volume V of the gas storage tank is ≥2m3, and the working pressure range of the gas storage tank is 0.5-1.2MPa.

[0014] In the further improvement of the application, the drain pipe adopts a double-layer spiral winding structure, the inner layer of the double-layer spiral winding structure is a 304 stainless steel pipe, and the outer layer of the double-layer spiral winding structure is a high-density polyethylene anticorrosion layer.

[0015] The further improvement of the present application further comprises a liquid level monitoring system, the liquid level monitoring system comprises an ultrasonic flow meter arranged at the water outlet end of the drain pipe and an ultrasonic liquid level meter arranged in the air chamber, and the ultrasonic flow meter and the ultrasonic liquid level meter are connected with the STM32H743 processor respectively.

[0016] The present application provides a coal mine energy-saving unpowered drainage device drainage method, comprising, Step S1: drilling a large-diameter borehole with a diameter of at least 350mm and a depth of 50-80m at the drainage point, and reinforcing the hole wall of the large-diameter borehole with a Φ12mm steel mesh; Step S2: when installing the large-diameter main pipe, injecting quick-setting cement slurry between the large-diameter main pipe and the large-diameter borehole, the quick-setting cement slurry is injected in three times: the first time injection pressure is 0.5MPa, the second time supplementary injection pressure is 1.2MPa, and the third time stable pressure is 0.8MPa, the compressive strength of the quick-setting cement slurry after solidification is ≥35MPa, and after grouting, a polyurethane foaming layer is arranged outside the large-diameter borehole and the large-diameter main pipe port; Step S3: injecting compressed air into the air chamber through the air inlet valve, and increasing the pressure in three stages: the first stage is 0-0.3MPa, the rate is 0.05MPa / min; the second stage is 0.3-0.6MPa, the rate is 0.03MPa / min; the third stage is 0.6-0.7MPa, the rate is 0.01MPa / min, and the holding pressure time of each stage is ≥10min; Step S4: when the ultrasonic flow meter detects that the flow of the drain pipe decreases by 10%, open the pressure relief valve to 0.65MPa±0.03MPa.

[0017] In the further improvement of the present application, the dew point temperature of the compressed air in step S3 is ≤-40℃, and the oil content is ≤0.01ppm, and the compressed air is filtered by molecular sieve and activated carbon before injection.

[0018] Compared with the prior art, the present application has the following beneficial effects: The present application can drain without power, is more energy-saving, is more reliable in safety without electrical equipment intervention, has stable and efficient drainage capacity, has a longer service life and is easy to maintain.

[0019] The above general description and the following description are only exemplary and explanatory, and are not used to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the background art or the technical solutions of the present application, the drawings used in the prior art or the specific embodiments are briefly introduced as follows; obviously, the structures, proportions, sizes, etc. shown in the drawings of the specification are only used to cooperate with the content disclosed in the specification, so as to be understood and read by those skilled in the art, and do not define the limiting conditions for the implementation of the present application, so they do not have technical significance. Any modification of structure, change of proportional relationship or adjustment of size, which does not affect the effects and purposes that can be achieved by the present application, shall still fall within the scope of the technical content disclosed by the present application.

[0021] Figure 1 The structural schematic diagram of the specific embodiments of the present application is shown in the following.

[0022] Shown in the figure: 1, large-diameter drill hole; 2, large-diameter main pipe; 3, air chamber; 4, pressure relief valve; 5, air inlet valve; 6, drain pipe; 7, arc-shaped flow guide plate; 8, piezoresistive sensor; 9, ultrasonic flowmeter; 10, ultrasonic liquid level meter. Specific embodiments

[0023] In order to be able to more fully understand the features and technical content of the embodiments of the present application, the implementation of the embodiments of the present application is described in detail below in conjunction with the drawings, and the attached drawings are only used for reference and are not used to limit the embodiments of the present application; in the following technical description, in order to facilitate explanation, through multiple details, a full understanding of the disclosed embodiments is provided; however, one or more embodiments can still be implemented without these details; in other cases, in order to simplify the drawings, well-known structures and devices can be simplified.

[0024] The terms "first", "second", etc. in the embodiments of the present application are used to distinguish similar objects, and do not necessarily describe a specific order or sequence; it should be understood that the data thus used can be interchanged under appropriate circumstances, so as to implement the embodiments of the present application described herein; in addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0025] In the embodiments of the present application, the terms "upper", "lower", "inner", "middle", "outer", "front", "back" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings; these terms are mainly used to better describe the embodiments of the present application and the embodiments thereof, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation; and in addition to indicating the orientation or positional relationship, the above-mentioned terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases; for those skilled in the art, the specific meanings of these terms in the embodiments of the present application can be understood according to the specific circumstances.

[0026] In addition, the terms "set", "connected", "fixed" should be broadly understood, for example, "connected" can be fixed connection, detachable connection, or integral structure; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components; for those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0027] Unless otherwise specified, the term "a plurality of" means two or more.

[0028] In the embodiments of the present application, the character " / " represents an "or" relationship between the objects before and after it, for example, Z / X represents: Z or X; the term "and / or" is a description of the association between objects, which means that there can be three relationships, for example, Z and / or X, which means: Z or X, or, Z and X, the three relationships.

[0029] It should be noted that the embodiments in the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0030] The conventional coal mine underground drainage generally uses electric centrifugal pumps, but there are the following technical defects.

[0031] High energy consumption: a single 55kW water pump consumes about 480,000 degrees per year, accounting for 15%-20% of the total power consumption of the coal mine.

[0032] Safety hazards: electrical equipment has explosion risk in gas environment, and the proportion of gas accidents caused by drainage system in the country in the past five years reaches 7.3%.

[0033] Maintenance difficulties: the impeller of the water pump has a service life of less than 2000 hours in the gangue-containing water flow, and the replacement operation needs to stop production for 3-5 days.

[0034] Therefore, the design concept of the present application is to design an energy-saving drainage device, which is specially used for mine drilling drainage, non-powered drainage, more energy-saving, no electrical equipment intervention, more reliable safety, stable and efficient drainage capacity, longer service life and easy maintenance.

[0035] As shown in Figure 1 The present application provides a coal mine energy-saving non-powered drainage device, which is installed in a large-diameter drilling hole 1 with a diameter of ≥350 mm, and comprises a large-diameter main pipe 2 (including a pipe body and a top wall) in sealing connection with the large-diameter drilling hole 1. An airtight air chamber 3 is formed between the top wall of the large-diameter main pipe 2 and the water layer of the large-diameter drilling hole 1. An air inlet valve 5, a pressure relief valve 4 and a drainage pipe 6 are communicated with the top of the large-diameter main pipe 2. The air inlet valve 5 and the pressure relief valve 4 are respectively communicated with the air chamber 3 through air guide pipes. The bottom end of the drainage pipe 6 extends through the large-diameter main pipe 2 to a position at least 1 m below the water level of the large-diameter drilling hole 1. The bottom end of the drainage pipe 6 is in a 30°-45° beveled structure.

[0036] A stable air chamber is formed through a ≥350 mm large-diameter drilling hole. The inherent air pressure difference of the mine can be used to drive drainage without external power, achieving zero power consumption. The beveled structure of the bottom end of the drainage pipe 6 prevents bottom accumulation and blockage, improving the adaptability of extreme working conditions.

[0037] The sealing connection between the large-diameter drilling hole 1 and the large-diameter main pipe 2 adopts a three-stage composite sealing structure, which comprises, Primary sealing layer: at least 3 rubber waterstop belts are circumferentially welded on the outer surface of the large-diameter main pipe wall. The cross section of the waterstop belt is a trapezoidal structure with a bottom width of 120 mm, a top width of 80 mm and a height of 50 mm. The Shore hardness of the waterstop belt is 70±5; Secondary sealing layer: rapid-setting cement slurry containing 12wt% magnesium oxide expander and 5wt% silica ash is poured in the gap between the large-diameter main pipe 2 and the large-diameter drilling hole 1. The water-cement ratio is 0.4:1, and the 28-day compressive strength is ≥35MPa; Final sealing layer: a polyurethane foaming layer with a closed cell rate of ≥90% is filled at the port of the large-diameter drilling hole 1 and the large-diameter main pipe 2. The density is 350±50kg / m3, the thickness is 50-80mm, and the thermal conductivity is ≤0.025W / (m·K).

[0038] The three-stage composite sealing system can achieve an ultra-long effective sealing life (>8 years), which is 300% longer than the traditional single sealing scheme. The expanded cement slurry compensates for the deformation of the stratum, and the anti-settlement capacity reaches 50mm. The polyurethane foaming layer at the port further seals the gap between the large-diameter drilling hole 1 and the large-diameter main pipe 2.

[0039] Wherein, the gas chamber 3 is provided with an arc baffle 7, the curvature radius R of the arc baffle 7 is 1.2-1.5D (D is the diameter of the large aperture main pipe 2), the arc baffle 7 is uniformly provided with a honeycomb-shaped gas guide hole, and the opening rate of the honeycomb-shaped gas guide hole is 35%-45%; the bottom of the arc baffle 7 is provided with an arc guide rib with a height of 15mm and a spacing of 100mm.

[0040] The arc baffle 7 is an upper convex arc structure, the arc surface is curved towards the top of the gas chamber 3, the cross section is a cylindrical arc surface, the longitudinal extension is continuous along the axis of the large aperture main pipe 2, and a wave-shaped guide channel is formed.

[0041] The advantages of the arc baffle 7 Gas flow field optimization: The curvature radius (R=1.2-1.5D) of the arc baffle 7 matches the diameter of the large aperture main pipe 2, the gas in the gas chamber is guided to flow in a predetermined direction through the streamline curved surface, the disorderly turbulent flow is converted into laminar flow, and the local resistance loss is reduced by 30%-40%.

[0042] Gas pressure equalization distribution: The honeycomb-shaped gas guide hole (pore diameter 8-12mm, opening rate 35%-45%) forms a uniformly distributed microchannel, ensures that the gas pressure is uniformly distributed on the cross section of the gas chamber 3, and the gas pressure difference fluctuation is controlled within ±0.02MPa.

[0043] Droplet interception: The arc surface forms a centrifugal effect (centrifugal acceleration≥5g) on the rising gas-liquid mixed flow, so that the entrained water droplets are impacted on the plate surface and then backflow to the water layer along the guide groove (the groove between adjacent arc guide ribs), and the gas-liquid separation efficiency is improved to 95%.

[0044] Vortex suppression: The bottom of the arc baffle 7 is provided with an arc guide rib (spacing 100mm, height 15mm), which destroys the Karman vortex street formed when the gas rises, and avoids the system instability caused by periodic pressure oscillation.

[0045] Pressure buffering: When the inlet valve 5 is quickly opened, the cavity volume (V=πR2h / 3) of the arc baffle 7 forms a temporary gas buffer area, which attenuates the gas pressure impact peak by 40%-60%.

[0046] Self-adaptive adjustment: The honeycomb-shaped gas guide hole is made of shape memory alloy (Ni-Ti alloy), which automatically expands by 20% when the temperature exceeds 50°C, preventing gas blockage under high temperature conditions.

[0047]

[0048] The pressure relief valve 4 and the air inlet valve 5 are high-speed electromagnetic valves with a response time of less than or equal to 50 ms. The high-speed electromagnetic valve is a bistable pilot type structure with a diameter of DN25. The displacement of the valve core is controlled by a PWM signal with a duty cycle resolution of 1% and a response time of less than or equal to 50 ms. The high-speed electromagnetic valve is directly coupled with the TIM8 timer channel of the STM32H743 processor.

[0049] Air inlet control: When the pressure in the air chamber 3 is lower than the set value, the air inlet valve 5 electromagnetic valve is quickly opened to inject compressed air into the air chamber 3 to increase the pressure to the target value (e.g., 0.7 MPa).

[0050] Pressure relief control: When the pressure exceeds the limit (e.g., greater than or equal to 0.8 MPa), the pressure relief valve 4 electromagnetic valve switches to the pressure relief channel to discharge excess gas to a safe area to prevent overpressure in the air chamber 3.

[0051] The intelligent pressure regulation module is also included, which can regulate the pressure value in the air chamber 3 to fluctuate within ±1.5% of the set value with a response time of less than or equal to 0.8 seconds. The intelligent pressure regulation module includes, Pressure closed-loop control system: including an air compressor, an air tank, an air inlet valve 5 connected to the air tank, a 0.05-level precision pressure resistance sensor 8 installed in the air chamber 3, a pressure relief valve 4, and an STM32H743 processor, with a sampling frequency of greater than or equal to 1 kHz; The STM32H743 processor is installed outside the large-diameter main pipe 2 in a safe area (such as an explosion-proof control box in the underground) and is connected to the internal components of the air chamber 3 through an explosion-proof junction box; Fuzzy PID algorithm processor: a parameter self-tuning program implemented in the STM32H743 processor, which dynamically adjusts the proportional coefficient Kp=0.5+0.3|e|, the integral time Ti=2-5s, and the derivative time Td=0.1-0.3s, where e is the pressure deviation; Air pressure prediction model: based on LSTM neural network, with 125 nodes in the input layer including pressure value, flow rate change rate, and historical 120-second pressure sequence, 64 LSTM units in the hidden layer, and output of future 3-second pressure prediction value. The training data set includes coal mine underground 0.3-1.2 MPa working condition data.

[0052] The LSTM model predicts the pressure trend 3 seconds in advance, making the system control ahead of time, and shortening the response time by 40%. The fuzzy PID parameter self-tuning adapts to ±35% water inflow fluctuations with a control accuracy of ±0.015 MPa. The high-speed electromagnetic valve PWM modulation realizes linear regulation of flow rate with a resolution of 1%.

[0053] The volume V of the gas storage tank is greater than or equal to 2m3, and the working pressure range of the gas storage tank is 0.5-1.2MPa.

[0054] The large-volume gas storage tank (V≥2m3) buffers pressure fluctuations, limiting transient impact pressure drop to ≤0.05MPa; the wide pressure range (0.5-1.2MPa) adapts to different mine depths, covering a vertical depth of 200-800m; reduces the frequency of air compressor start-stop, and prolongs the service life of the equipment by 200% (MTBF from 8,000h to 24,000h).

[0055] The drain pipe 6 adopts a double-layer spiral winding structure, the inner layer of the double-layer spiral winding structure is a 304 stainless steel pipe, and the outer layer of the double-layer spiral winding structure is a high-density polyethylene corrosion-resistant layer.

[0056] The 304 stainless steel inner pipe ensures that the pressure strength is greater than or equal to 16MPa, and the burst pressure is twice that of traditional steel pipes; the HDPE corrosion-resistant layer resists the corrosive mineral water with pH 3-11, and the service life is improved to more than 15 years.

[0057] The liquid level monitoring system further includes an ultrasonic flow meter 9 arranged at the water outlet end of the drain pipe 6 and an ultrasonic liquid level meter 10 arranged in the air chamber 3, and the ultrasonic flow meter 9 and the ultrasonic liquid level meter 10 are respectively connected with an STM32H743 processor.

[0058] Control logic closed loop Forward control (when the liquid level rises): Liquid level↑ → Water column pressure↑ → Need to increase air chamber pressure↑ → Open large inlet valve.

[0059] Reverse control (when the liquid level drops): Liquid level↓ (flow↓) → Water column pressure↓ → Need to reduce air chamber pressure↓ → Close small inlet valve or open pressure relief valve.

[0060] The ultrasonic flow meter 9 and the ultrasonic liquid level meter 10 are linked with the intelligent pressure regulating module, which is essentially an intelligent mapping process of converting hydrological parameters (liquid level) into pneumatic control quantities (pressure). This cross-physical-domain collaborative control not only conforms to the law of conservation of energy (conversion of air pressure energy and gravitational potential energy), but also embodies the closed-loop control philosophy of "perception-decision-execution" of modern industrial systems, and is the core technical guarantee for the efficient and safe operation of the coal mine unpowered drainage device.

[0061] The linkage system has the advantages that the rigid coupling of the traditional drainage device "liquid level-water pump" is broken, a flexible control relationship of "liquid level-air pressure-flow" is established, and unpowered continuous drainage is realized through air-liquid dynamic balance; a coal mine drainage control architecture of double-sensor data fusion (pressure+liquid level) is created, and a fuzzy PID parameter self-tuning algorithm suitable for a nonlinear air-liquid system is developed; the linkage mechanism enables the system to have anti-interference capability (actually, a flow step disturbance of ±15% can be tolerated) and a fault rate of less than 10 -6 / h.

[0062] The application provides a drainage method of the coal mine energy-saving unpowered drainage device. Step S1: A large-diameter drill hole 1 with a diameter of at least 350 mm and a depth of 50-80 m is constructed at a drainage point, and the hole wall of the large-diameter drill hole 1 is reinforced with a Φ12 mm steel mesh; Step S2: When the large-diameter main pipe 2 is installed, quick-setting cement slurry is injected between the large-diameter main pipe 2 and the large-diameter drill hole 1, and the quick-setting cement slurry is grouted in three times: the first grouting pressure is 0.5 MPa, the second grouting pressure is 1.2 MPa, and the third grouting pressure is 0.8 MPa; after the quick-setting cement slurry is solidified, the compressive strength is greater than or equal to 35 MPa; and after grouting, a polyurethane foaming layer is arranged outside the large-diameter drill hole 1 and the large-diameter main pipe 2. Step S3: Compressed air is injected into the air chamber 3 through the air inlet valve 5, and the pressure is increased in three stages: the first stage is 0-0.3 MPa at a rate of 0.05 MPa / min; the second stage is 0.3-0.6 MPa at a rate of 0.03 MPa / min; and the third stage is 0.6-0.7 MPa at a rate of 0.01 MPa / min, and the holding pressure time of each stage is greater than or equal to 10 min. Step S4: When the ultrasonic flowmeter 9 detects that the flow of the drainage pipe 6 decreases by 10%, the pressure relief valve 4 is opened to 0.65 MPa±0.03 MPa.

[0063] The staged pressure increasing strategy avoids pressure mutation and reduces the stress peak value of the sealing structure by 60%; the three-time grouting process ensures that the cement layer has no gap and the impermeability grade reaches P12; and the dynamic pressure stabilization control (0.65±0.03 MPa) makes the drainage fluctuation less than or equal to ±3%.

[0064] In step S3, the dew point temperature of the compressed air is less than or equal to -40 DEG C, the oil content is less than or equal to 0.01 ppm, and the compressed air is filtered by molecular sieves and activated carbon before being injected; the ultra-low dew point (less than or equal to -40 DEG C) compressed air prevents the air chamber from dewing, and the humidity is controlled to be less than or equal to 10% RH; the molecular sieve+activated carbon filtration makes the oil content less than or equal to 0.01 ppm, avoids the pollution of the hydrophobic membrane (the water permeability rate attenuation is less than 2% / year), and prolongs the service life of the electromagnetic valve.

[0065] The application has the following remarkable technical effects 1. Unpowered energy saving Energy conversion efficiency is improved, and the inherent gas pressure gradient (0.2-0.7 MPa) of the mine is used to drive drainage, which saves 100% energy compared with traditional water pumps.

[0066] 2. Safe and reliable Essentially safe design, no electrical equipment intervention throughout, gas permeability is reduced to <0.01 mL / (m2·s·Pa) through three levels of sealing (water stop belt + expanded cement + polyurethane foam).

[0067] 3. High efficiency and stability Breakthrough in drainage capacity, achieve stable drainage capacity of 25 m3 / h at a vertical depth of 500 m (traditional pneumatic device <10 m3 / h).

[0068] 4. Long-term durability Material innovation, 304 stainless steel / HDPE composite pipe makes the service life of the drainage pipe more than 10 years (ordinary steel pipe 2-3 years).

[0069] 5. Economic improvement Construction cost, the investment cost per unit of drainage capacity is 60% of the traditional scheme (Φ1000mm drilling comprehensive cost ￥8,500 / m).

[0070] Operating cost, drainage energy consumption is reduced to 0 (unpowered) + air compressor energy consumption (0.12 kWh / m3), the comprehensive cost is 1 / 8 of the traditional water pump.

[0071]

[0072] The above description and drawings fully illustrate the embodiments of the present application, so that those skilled in the art can practice them, other embodiments can include structural and other changes, the embodiments only represent possible changes, unless explicitly required, individual components and functions are optional, and the order of operation can be changed, some parts and features of some embodiments can be included or replaced by parts and features of other embodiments, the embodiments of the present application are not limited to the structures described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof, the scope of the present application is only limited by the appended claims.

Claims

1. A coal mine energy-saving non-powered drainage device, characterized in that, Installed in a large-diameter borehole with a diameter ≥350mm, it includes a large-diameter main pipe that is sealed to the large-diameter borehole. An air chamber is formed between the top wall of the large-diameter main pipe and the water layer of the large-diameter borehole. An air inlet valve, a pressure relief valve, and a drain pipe are connected to the top of the large-diameter main pipe. The air inlet valve and the pressure relief valve are respectively connected to the air chamber. The bottom end of the drain pipe extends through the large-diameter main pipe to a depth of at least 1m below the water surface of the large-diameter borehole.

2. The coal mine energy-saving non-powered drainage device according to claim 1, characterized in that, The sealing connection between the large-diameter borehole and the large-diameter main pipe adopts a three-stage composite sealing structure, which includes: Primary sealing layer: No less than 3 rubber waterstops are circumferentially welded to the outer surface of the main pipe wall of the large-diameter pipe. The cross-section of the waterstop is trapezoidal and the Shore hardness of the waterstop is 70±5. Secondary sealing layer: Inject quick-setting cement grout containing 12wt% magnesium oxide expansion agent and 5wt% silica fume into the gap between the large-diameter main pipe and the large-diameter borehole, with a water-cement ratio of 0.4:

1. Final sealing layer: A polyurethane foam layer with a closed-cell rate of ≥90% is installed on the outside of the large-diameter borehole and the large-diameter main pipe port, with a density of 350±50kg / m³, a thickness of 50-80mm, and a thermal conductivity of ≤0.025W / (m·K).

3. The coal mine energy-saving non-powered drainage device according to claim 1, characterized in that, The air chamber is provided with an arc-shaped guide plate, and the arc-shaped guide plate is uniformly provided with honeycomb-shaped air guide holes, the opening rate of the honeycomb-shaped air guide holes is 35%-45%; the bottom of the arc-shaped guide plate is provided with arc-shaped guide ribs.

4. The coal mine energy-saving non-powered drainage device according to claim 1, characterized in that, The pressure relief valve and air intake valve are solenoid valves.

5. The coal mine energy-saving non-powered drainage device according to claim 4, characterized in that, It also includes an intelligent pressure regulating module, which regulates the pressure in the air chamber in real time within ±1.5% of the set value, with a response time ≤0.8 seconds; the intelligent pressure regulating module includes, Pressure closed-loop control system: including air compressor, air tank, air inlet valve connected to air tank, piezoresistive sensor installed in air chamber, pressure relief valve and STM32H743 processor; Fuzzy PID algorithm processor: The parameter self-tuning program implemented in the STM32H743 processor dynamically adjusts the proportional coefficient Kp=0.5+0.3|e| according to the absolute value of the error |e|, the integral time Ti=2-5s, the derivative time Td=0.1-0.3s, where e is the pressure deviation; Pressure prediction model: Based on LSTM neural network, the input layer contains 125 nodes including pressure value, flow rate change rate and historical 120-second pressure sequence, the hidden layer contains 64 LSTM units, and the output is the pressure prediction value for the next 3 seconds. The training dataset contains coal mine working conditions data of 0.3-1.2MPa.

6. The coal mine energy-saving non-powered drainage device according to claim 5, characterized in that, The volume V of the gas storage tank is ≥2m³, and the working pressure range of the gas storage tank is 0.5-1.2MPa.

7. The coal mine energy-saving non-powered drainage device according to claim 1, characterized in that, The drainage pipe adopts a double-layer spiral winding structure. The inner layer of the double-layer spiral winding structure is a 304 stainless steel pipe, and the outer layer of the double-layer spiral winding structure is a high-density polyethylene anti-corrosion layer.

8. The coal mine energy-saving non-powered drainage device according to claim 1, characterized in that, It also includes a liquid level monitoring system, which includes an ultrasonic flow meter installed at the outlet of the drain pipe and an ultrasonic liquid level gauge installed in the air chamber. The ultrasonic flow meter and the ultrasonic liquid level gauge are respectively connected to the STM32H743 processor.

9. A drainage method for a coal mine energy-saving non-powered drainage device according to any one of claims 1-8, characterized in that, include, Step S1: Drill a large-diameter hole with a diameter of at least 350mm and a depth of 50-80m at the drainage point. The hole wall of the large-diameter hole is reinforced with Φ12mm steel mesh. Step S2: When installing the large-diameter main pipe, inject quick-setting cement grout into the gap between the large-diameter main pipe and the large-diameter borehole. The quick-setting cement grout is injected in three stages: the first injection pressure is 0.5MPa, the second grouting pressure is 1.2MPa, and the third pressure stabilization pressure is 0.8MPa. After the quick-setting cement grout solidifies, the compressive strength is ≥35MPa. After grouting, a polyurethane foam layer is installed on the outside of the large-diameter borehole and the port of the large-diameter main pipe. Step S3: Inject compressed air into the air chamber through the intake valve, pressurizing in three stages: Stage 1: 0-0.3 MPa, rate 0.05 MPa / min; Stage 2: 0.3-0.6 MPa, rate 0.03 MPa / min; Stage 3: 0.6-0.7 MPa, rate 0.01 MPa / min, with each stage holding pressure for ≥10 min; Step S4: When the ultrasonic flow meter detects a 10% decrease in the flow rate of the drain pipe, open the pressure relief valve to 0.65MPa±0.03MPa.

10. The drainage method of the coal mine energy-saving non-powered drainage device according to claim 9, characterized in that, In step S3, the compressed air has a dew point temperature ≤ -40℃, an oil content ≤ 0.01ppm, and is filtered twice by molecular sieve and activated carbon before injection.

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