Drainage system for large water sump of return airway

Abstract

The invention discloses a drainage system for a large water sump of a return airway. The drainage system comprises a high-pressure water pumping pipe connected with the large water sump of the return airway. The high-pressure water pumping pipe is respectively connected with a main drainage pipeline and a standby drainage pipeline through a water pumping pipe tee joint; the other ends of the main drainage pipeline and the standby drainage pipeline are connected to a main drainage pipe which is connected to a coal mine drainage system pipeline; the main drainage pipeline comprises a water inlet high-pressure pipe, a first straight-through pipe, a main drainage pump and a water outlet high-pressure pipe which are connected in sequence; the main drainage pump and the standby drainage pump are connected into the main drainage pipeline and the standby drainage pipeline respectively, when the drainage pumps need to be switched, the main drainage pipeline and the standby drainage pipeline can be directly switched through the valve, the pipeline reversing time can be shortened, and the accident rate can be reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of coal mine drainage facilities, and particularly relates to a drainage system for a large water tank in a return airway. Background Technology

[0002] Return airway is usually located in the upper part of the coal seam or in the rock strata underground. It is susceptible to the infiltration of rock fissure water and old working water. The large water tank can be used as a "temporary water storage pool" to collect the water inflow in the return airway and related mining areas (such as adjacent working faces) and prevent the water from spreading to the transport roadway and working face.

[0003] The amount of water flowing into the well often varies with the season and the depth of mining. A large water tank can regulate "instantaneous large water inflow" (such as sudden fissure water inflow), avoid the drainage pump from frequently starting and stopping due to "overflow", extend the equipment life and ensure continuous drainage.

[0004] Existing large water tanks typically have one operating pump and one standby pump. When one pump is under maintenance or malfunctions, the pipeline is rerouted to the next pump. However, rerouting takes time, and especially during water surges, it significantly increases the accident rate. Summary of the Invention

[0005] The purpose of this invention is to provide a drainage system for a large water tank in a return airway, which connects the main drainage pump and the standby drainage pump in parallel through parallel pipelines, and designs controls on the pipelines to reduce the time spent switching pipelines and lower the accident rate.

[0006] The present invention adopts the following technical solution: a drainage system for a large water tank in a return airway, comprising a high-pressure pumping pipe connected to the large water tank in the return airway; The high-pressure water pumping pipe is connected to the main drainage pipe and the backup drainage pipe respectively through a water pumping pipe tee; The other end of both the main drainage pipeline and the backup drainage pipeline is connected to the main drainage pipe, which is connected to the coal mine drainage system pipeline. The main drainage pipeline includes, in sequence, an inlet high-pressure pipe, a first straight pipe, a main drainage pump, and an outlet high-pressure pipe; The pumping pipe tee has a slip flange and a solid flange at both ends, and the first straight pipe has a slip flange and a solid flange at both ends.

[0007] The beneficial effects of this invention are: by connecting the main drainage pump and the standby drainage pump to the main drainage pipeline and the standby drainage pipeline respectively, when it is necessary to switch the drainage pump, the main drainage pipeline and the standby drainage pipeline can be switched directly through the valve, which can reduce the time spent on rerouting and reduce the accident rate. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the structure of a large water tank drainage system in a return airway according to an embodiment of the present invention; Figure 2This is a schematic diagram of the internal structure of the first through pipe in an embodiment of the present invention.

[0009] Among them: 10. High-pressure water pumping pipe; 11. Water pumping pipe tee; 20. Main drainage pipe; 21. Inlet valve; 22. Inlet high-pressure pipe; 23. First straight pipe; 24. Main drainage pump; 25. Outlet high-pressure pipe; A. Filter screen; B. Baffle; C1. First filter hole; C2. Second filter hole; C3. Third filter hole; C4. Fourth filter hole; C5. Fifth filter hole; 30. Backup drainage pipeline; 40. Main drain pipe; 41. Drain pipe tee; 42. Second straight pipe. Detailed Implementation

[0010] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0011] The existing drainage system in the large water tank of the North 2 150 return airway uses two D85 water pumps operating in parallel. However, when the main water pump is under maintenance or malfunctions, the pipeline must be manually switched to the standby pump. This operation is not only time-consuming and labor-intensive, but also carries the risk of drainage interruption during the switching process. Due to the complex underground environment and limited space, manual pipe-switching operations are prone to safety accidents and also affect the continuous drainage capacity of the settling tank, thus threatening the stability and safety of the entire roadway drainage system. To solve these problems, there is an urgent need for a drainage system for the large water tank in the return airway that can automatically switch between the main and standby drainage pumps and ensure continuous drainage, thereby improving the reliability of system operation, reducing maintenance risks, and meeting the needs of long-term stable operation in coal mines.

[0012] This utility model discloses a drainage system for a large water tank in a return airway, such as... Figure 1 As shown, it includes a high-pressure pumping pipe 10 connected to the large water tank in the return airway; the high-pressure pumping pipe 10 is connected to the main drainage pipeline 20 and the backup drainage pipeline 30 respectively through a pumping pipe tee 11; the other ends of the main drainage pipeline 20 and the backup drainage pipeline 30 are both connected to the main drainage pipe 40, which is connected to the coal mine drainage system pipeline; the main drainage pipeline 20 includes an inlet high-pressure pipe 22, a first straight pipe 23, a main drainage pump 24 and an outlet high-pressure pipe 25 connected in sequence; wherein, the two ends of the pumping pipe tee 11 are a loose flange and an integral flange respectively, and the two ends of the first straight pipe 23 are a loose flange and an integral flange respectively.

[0013] The present invention connects the main drainage pump 24 and the standby drainage pump to the main drainage pipeline 20 and the standby drainage pipeline 30, respectively. When it is necessary to switch the drainage pump, the main drainage pipeline and the standby drainage pipeline can be switched directly through the valve, which can reduce the time spent on rerouting and reduce the accident rate.

[0014] By setting up a parallel structure of the main drainage pipeline 20 and the backup drainage pipeline 30, combined with the modular connection design of key pipeline components, the system achieves rapid switching and continuous drainage between the main and backup pumps. The system has a reasonable overall layout and is easy to install and maintain, making it particularly suitable for applications in coal mines where continuous drainage is required and working space is limited. Its core lies in using the pumping pipe tee 11 to distribute water from the water tank to two independent but functionally equivalent drainage paths, and improving the assembly flexibility and sealing performance between components through standardized flange interfaces, thereby ensuring stable operation of the system under various working conditions.

[0015] The high-pressure water extraction pipe 10 is used to draw water from the large water tank in the return airway out of the tank, undertaking the initial water conveyance task. This pipe has good pressure resistance and can withstand long-term operation under high water pressure conditions underground. Its diameter can be set according to the actual drainage requirements, and its length can be flexibly adjusted according to the site layout. One end of the high-pressure water extraction pipe 10 is connected to the water tank inlet, and the other end is connected to the extraction pipe tee 11, serving as the main water inlet channel for the entire drainage system.

[0016] The tee 11 is a key component for water diversion. Its structure is T-shaped or Y-shaped, with three interfaces: one inlet connecting to the high-pressure pumping pipe 10, and two outlets connecting to the main drainage pipe 20 and the backup drainage pipe 30, respectively. This tee is constructed from 4-inch (approximately DN100) welded pipe and flanges, preferably made of Q235B carbon structural steel, possessing sufficient mechanical strength and corrosion resistance. Its two outlet ends are equipped with different types of flanges: one is a loose flange, and the other is an integral flange. The loose flange can be freely adjusted with bolts for easy alignment and installation; the integral flange is fixed to the pipe body, providing a stable connection reference surface. This combined design eliminates the need for complete cutting and welding when disassembling or replacing any drainage pipe, significantly improving maintenance efficiency.

[0017] The main drainage pipeline 20 and the backup drainage pipeline 30 are two parallel drainage channels with equivalent functions. Under normal circumstances, the main drainage pipeline 20 undertakes the main drainage task. When the main drainage pump 24 is under maintenance or malfunctioning, it can be switched to the backup drainage pipeline 30 through valve control to achieve uninterrupted drainage. Both pipelines are independently connected to the main drainage pipe 40 and eventually merge into the original drainage system network of the coal mine, ensuring the integrity and compatibility of the drainage path.

[0018] The main drainage pipeline 20 is composed of multiple functional sections connected in sequence: the inlet high-pressure pipe 22 is used to receive water from the pumping pipe tee 11, and its material is the same as that of the high-pressure pumping pipe 10, which has good pressure bearing capacity; the first straight pipe 23 is located between the inlet high-pressure pipe 22 and the main drainage pump 24, and serves as a transitional connector. Its two ends also adopt the structure of a loose flange at one end and an integral flange at the other end, which facilitates quick docking and disassembly with adjacent components; the main drainage pump 24 is the core power unit of the system, and a multi-stage centrifugal pump such as D85-45×7 can be selected, with a rated flow of about 85m³ / h and a head of up to 315m, which meets the drainage needs of deep tunnels; the outlet high-pressure pipe 25 is responsible for transporting the water pressurized by the main drainage pump 24 to the main drainage pipe 40. Its pipe material is the same as that of the aforementioned high-pressure pipeline to ensure the consistency of system pressure.

[0019] The main drainage pipe 40 serves as the confluence channel for the main and backup pipelines, and typically uses a larger diameter steel pipe (such as DN200) to accommodate the maximum flow rate of simultaneous drainage from both pipelines. One end connects to the outlet of the main drainage pipe 20 and the backup drainage pipe 30, while the other end connects to the existing main drainage network of the coal mine, achieving seamless integration with the overall mine drainage system. This pipe should have an anti-corrosion coating to withstand the harsh underground environment, including humidity and sulfur-containing gases.

[0020] All flange connections are equipped with spiral wound gaskets or graphite composite gaskets, secured with high-strength bolts to ensure a tight seal and prevent leakage or pressure seepage. The pairing of loose flanges and integral flanges not only increases the tolerance for errors during on-site installation but also greatly simplifies the replacement of pump bodies or pipe sections during later maintenance, avoiding the risks of hot work associated with traditional welding connections.

[0021] Through the above technical solution, this invention realizes a compact, flexible, and reliable drainage system for a large water tank in a return airway. When the water tank needs drainage, the high-pressure pumping pipe 10 introduces the accumulated water into the pumping pipe tee 11, and the water flow can enter the main drainage pipe 20 or the backup drainage pipe 30 according to the operating strategy. When the main drainage pump 24 is working normally, the water flows through the inlet high-pressure pipe 22, the first straight pipe 23, the main drainage pump 24, and the outlet high-pressure pipe 25 to the main drainage pipe 40 for discharge; once the main pump needs to be shut down for maintenance, only the valve on the corresponding pipeline needs to be closed and the backup path opened, and the backup pump can take over the drainage task, without interrupting the drainage operation. Since both the pumping pipe tee 11 and the first straight pipe 23 adopt a combination connection of loose flange and integral flange, the pipeline disassembly and assembly are more convenient, significantly shortening maintenance time and reducing the safety risks caused by manual intervention.

[0022] By incorporating a parallel main and backup drainage pipeline structure and a standardized flange interface design, the technical problem of drainage interruption due to pump maintenance in existing technologies has been solved. This ensures that pumps are always running in the water tank, guaranteeing the continuity and stability of the roadway drainage system. Furthermore, the modular pipeline connection method enhances the system's maintainability and adaptability, making it particularly suitable for widespread application in the confined and complex environments of underground coal mines.

[0023] Valves are installed on both the main drainage pipeline 20 and the backup drainage pipeline 30. Valves are mechanical devices used to control the flow of fluid. They can be installed at any suitable location on the pipeline, but are typically placed near the outlet of the pumping tee 11 or at key points before or after the drainage pump to effectively isolate and connect the corresponding pipeline. These valves can be manual or automatic valves driven by electricity, pneumatics, or hydraulics. Specific types include, but are not limited to, gate valves, globe valves, ball valves, or butterfly valves. In practical applications, considering the humid, dusty, and inconvenient maintenance environment underground, flanged ball valves or gate valves made of stainless steel or cast steel with good sealing performance, flexible opening and closing, and corrosion resistance can be selected.

[0024] The valve on the main drainage pipeline 20 is used to control the on / off state of the pipeline where the main drainage pump 24 is located. When the main drainage pump is working normally, the valve is in the open state, allowing water to flow from the high-pressure pumping pipe 10 through the pumping pipe tee 11 into the main drainage pipeline 20, and then be pressurized by the main drainage pump 24 and discharged into the main drainage pipe 40. When the main drainage pump needs to be repaired or malfunctions, the main pipeline water flow can be cut off by closing the valve to prevent water from flowing back into non-operating pipelines, while providing safe isolation conditions for maintenance work.

[0025] Similarly, the valve on the backup drainage pipe 30 is used to control the on / off status of the pipe where the backup drainage pump is located. When the main drainage pump is not in use, opening this valve allows water to flow through the backup drainage pipe 30 into the main drainage pipe 40, achieving a seamless switch of drainage functions. The two valves can be coordinated and controlled through electrical interlocking or a control system to prevent pressure imbalance or water flow interference caused by both lines being open simultaneously.

[0026] The installation location of the aforementioned valves can be adjusted according to the site layout, but they should generally be placed near the branch point of the pumping pipe tee (11-way branch) to maximize isolation between branches. The nominal diameter (DN) of the valve should match the connected pipeline, such as DN100 or DN150, to ensure flow capacity matching and reduce local resistance loss. Flange connection is preferred for ease of disassembly and maintenance, and to ensure reliable sealing.

[0027] Through the above technical solution, this invention achieves independent on / off control of the main drainage pipeline 20 and the backup drainage pipeline 30. Because valves are installed on each of the two pipelines, either pipeline can be selectively opened or closed according to operational needs, effectively preventing backflow or crossflow of water in non-operating pipelines, thus improving the stability and safety of system operation. Simultaneously, this design simplifies the pipeline switching process, reduces the frequency of manual intervention and operational risks, and provides reliable safety isolation measures for equipment maintenance. Combining the structural configuration of the high-pressure pumping pipe 10 and the pumping pipe tee 11, this embodiment further optimizes the fluid control logic in the dual-pump parallel operation mode, enabling the return airway large water tank drainage system to maintain continuous and efficient drainage capacity under different operating conditions.

[0028] The backup drainage pipeline 30 has the same pipe connection structure as the main drainage pipeline 20. "Same pipe connection structure" means that the backup drainage pipeline 30 is completely identical to the main drainage pipeline 20 in terms of overall layout, component types, connection sequence, interface type, pipe diameter specifications, and the arrangement of key components. Specifically, the backup drainage pipeline 30 also includes a sequentially connected inlet high-pressure pipe, a first straight pipe, a backup drainage pump, and an outlet high-pressure pipe. The connection methods between each component adopt the same flange connection, welding, or threaded connection process. The pipe material can be carbon steel, stainless steel, or high-strength composite material. The nominal pipe diameter is typically DN100 (4 inches), and the wall thickness is not less than 6mm to withstand long-term operating stress in the high-pressure drainage environment of the well.

[0029] The first straight pipe 23, a key connector shared by the main and backup drainage pipes, has a slip-on flange and an integral flange at both ends. This design allows for axial adjustment and angle compensation during installation and disassembly, improving on-site assembly flexibility and effectively mitigating stress concentration issues caused by geological settlement or vibration. Since the backup drainage pipe 30 uses the exact same connection structure as the main drainage pipe 20, its first straight pipe also has the same end connection type, ensuring interchangeability of all corresponding interfaces throughout the system, facilitating standardized manufacturing and rapid replacement and maintenance.

[0030] Furthermore, although the main drainage pump 24 and the standby drainage pump are independent devices, they share the same technical parameters such as model, flow rate, head, and power. For example, both can be selected as D85 multistage centrifugal pumps with a rated flow rate of approximately 85 m³ / h, a matching motor power of no less than 75 kW, and a rated working pressure of over 3.0 MPa, making them suitable for deep well high-head drainage scenarios. Because the main and standby pipeline structures are identical and the pump inlet and outlet connection dimensions are uniform, pump replacement or rotation operation requires no additional modification to the pipeline system, significantly improving operation and maintenance efficiency.

[0031] In practical applications, both the main drainage pipeline 20 and the backup drainage pipeline 30 are connected to the same high-pressure pumping pipe 10 via a pumping tee 11, and their on / off states are controlled by valves such as gate valves or butterfly valves installed on their respective pipelines. When the main drainage pump 24 needs to be shut down for maintenance, the valve on the main drainage pipeline is closed, and the corresponding valve on the backup drainage pipeline is opened simultaneously, automatically switching the water flow to the backup path. Since the two pipelines have the same geometric length, number of bends, pipe diameter variation pattern, and local resistance coefficient distribution, the total resistance characteristics of the system remain almost unchanged, avoiding pressure surges or flow attenuation caused by pipeline differences, and achieving a smooth transition.

[0032] Through the above technical solution, the present invention achieves a high degree of symmetry between the main drainage pipeline and the backup drainage pipeline in terms of physical structure and hydraulic performance. Because the backup drainage pipeline 30 and the main drainage pipeline 20 adopt the same pipeline connection structure, the system can maintain consistent fluid dynamic behavior and mechanical connection reliability when either pipeline is put into operation. This solves the problems of unstable switching and reduced drainage capacity caused by the asymmetry between the main and backup pipelines in traditional systems, thereby ensuring continuous, efficient, and safe drainage of the large water tank in the return airway under various operating conditions, and improving the redundancy and operational robustness of the coal mine drainage system.

[0033] How to efficiently merge the outlet ends of the main drainage pipeline and the backup drainage pipeline and connect them to the coal mine drainage system, reduce the number of connection nodes, lower the risk of leakage, and improve the system integration and layout rationality in the confined underground space, is a key issue currently faced by the drainage system of the large water tank in the return airway in actual operation. In the existing technology, the main and backup water pumps are independently connected to the external drainage network, resulting in many interfaces and complex pipelines. During maintenance and switching, frequent disassembly and assembly of pipelines are required, which is not only cumbersome but also prone to leakage due to poor sealing, affecting the continuity of drainage and operational safety. Especially in the application scenario of the large water tank in the North 2 150 return airway, only two D85 water pumps are configured. Once the main pump stops operating for maintenance or malfunctions, if a stable switch of the drainage path cannot be achieved quickly, it will directly threaten the overall drainage capacity of the roadway, and may lead to safety hazards such as backflow of water. Therefore, there is an urgent need for a water outlet confluence scheme that is simple in structure, reliable in connection, and easy to maintain, so as to ensure that the main pump or the standby pump can be smoothly connected to the coal mine drainage system through a unified outlet, and avoid the system vulnerability caused by multiple connections.

[0034] In this embodiment, a shared drainage tee 41 is used to centrally converge the outlets of the main drainage pipe 20 and the backup drainage pipe 30, and then connects them to the coal mine drainage system via a second straight pipe 42, thus forming a "two-in-one-out" convergence structure. This design effectively integrates the outlet paths of the dual-pipeline system, improving the system's integration level and operational reliability.

[0035] Among them, the main drainage pipeline 20 is the main channel for transmitting high-pressure water flow. One end of it is connected to the pumping pipe tee 11, and the other end is the water outlet. It is responsible for transporting the water discharged by the main drainage pump 24 to the downstream confluence node. The main drainage pipeline 20 undertakes the normal drainage task in the whole system. Under normal working conditions, it remains open and continuously discharges the water accumulated in the large water tank of the return airway.

[0036] The backup drainage pipeline 30 is structurally symmetrical to the main drainage pipeline 20 and has the same function, serving to replace the main drainage pump 24 in completing the drainage task when the pump is stopped, under maintenance, or malfunctions. This pipeline also uses the same pipe diameter, material, and connection method as the main drainage pipeline to ensure that the flow characteristics and pressure-bearing capacity match, avoiding uneven water distribution or starting difficulties due to resistance differences. The backup drainage pipeline 30 is normally closed and is only activated via a valve control when the main pump fails, ensuring uninterrupted drainage operations.

[0037] The outlet end refers to the end interface of the main drainage pipe 20 and the backup drainage pipe 30 on the side away from the water tank, that is, the position where they are connected to the drainage pipe tee 41 respectively; this position is equipped with a standard flange connection structure for easy assembly and disassembly, while ensuring sealing performance. The two outlet ends are connected to the drainage pipe tee 41 as independent water inlets, forming a double-sided water inlet layout, which allows water flows from different pump sets to dynamically merge inside the tee.

[0038] The drain tee 41 is a pipe fitting with three connection ports. Two horizontal ports connect to the outlets of the main drain pipe 20 and the backup drain pipe 30, respectively. The third port, extending vertically downwards or coaxially, connects to a second straight pipe 42 to discharge the combined water flow. The tee is entirely made of cast steel or welded steel pipe, with smooth transitions in the internal flow channels to reduce local head loss. Its inlet end is equipped with a combination of a loose flange and an integral flange, allowing for a certain range of installation error compensation and improving on-site assembly convenience. As a core confluence element, the drain tee 41 achieves spatial integration of the main and backup pipe flows, avoiding the multiple interface problems associated with separate connections to external pipe networks.

[0039] The second straight pipe 42 is a straight pipe section used to connect the outlet end of the drainage tee 41 to the coal mine drainage system pipeline. Its length can be flexibly adjusted according to the on-site installation space. The pipe diameter is consistent with the outlet of the drainage tee 41, and the material is the same as the main / backup pipeline. It is fixed below the tee by welding or flange connection. The function of the second straight pipe 42 is to provide a buffer transition section, so that the water flow after merging tends to be stable before entering the main pipeline, preventing turbulence disturbance from affecting the operation of the downstream system.

[0040] All the above components are connected by flange bolts and sealed with rubber gaskets. All welds are non-destructive tested according to pressure pipeline standards to ensure the safety and durability of the entire system under high-pressure conditions. The outlets of the main drainage pipe 20 and the backup drainage pipe 30 are symmetrically distributed on both sides of the drainage tee 41, which is beneficial for stress balance and maintenance operations. The second straight pipe 42 extends vertically or inclined to facilitate venting and emptying, adapting to complex underground terrain conditions.

[0041] The above technical solution achieves a high degree of integration between the main drainage pipeline and the backup drainage pipeline, simplifying the original requirement of two independent interfaces to the coal mine drainage system to a single outlet connection. This significantly reduces the number of external connection points and lowers the risk of potential leaks. Simultaneously, the use of standardized pipe fittings and modular design results in a compact and clearly laid-out manifold structure, making it particularly suitable for environments with limited underground space. Furthermore, this structure supports seamless switching between the main and backup pumps. Regardless of which pump is operating, its drainage can smoothly flow through the drainage tee 41 into the second straight pipe 42 and then into the coal mine drainage system pipeline, ensuring the continuity and stability of the water tank drainage. This solves the safety hazards and inefficiencies caused by manual pipe repositioning, ultimately achieving the technical effect of improving the system's automation level and operational reliability. This embodiment can be applied to water tank drainage systems in various mine roadways, as well as industrial fluid transport scenarios requiring redundant dual-pump configurations.

[0042] Impurities carried in the water can easily enter the pipes and pumps during drainage system operation, causing blockage of the main drainage pump impeller, wear of seals, or reduction of the pipe flow cross-section, leading to equipment overload, decreased efficiency, or even sudden shutdown. This is especially true in long-term, continuous drainage scenarios such as large water tanks in underground coal mine return airways, where the water typically contains coal dust, silt, and other suspended particulate matter. Without effective filtration and protection measures, the system's stability and maintainability will be significantly reduced. Furthermore, the system's reliability requirements are even higher during pump maintenance or switching operations; any malfunction caused by impurities can lead to drainage interruption, threatening mine safety. Therefore, it is crucial to install effective solid-liquid separation structures in critical pipeline sections and prevent secondary pollution from filter element failure.

[0043] Therefore, as Figure 2 As shown, in this embodiment, a filter screen A is provided inside the first straight pipe 23; a baffle B is provided on the inner wall near the water outlet end of the first straight pipe 23.

[0044] The above technical solution improves the adaptability of the drainage system to complex water quality by integrating filtration and limiting functional units in the fluid channel. Specifically, filter A intercepts solid particles moving with the water flow, preventing them from entering the main drainage pump 24 and causing mechanical damage; baffle B is located downstream of the filter screen to prevent debris accumulated at the front of the filter screen from being washed away by the high-speed water flow, thereby preventing captured impurities from re-entering downstream components of the system.

[0045] Filter A is a cylindrical or multi-layered annular structure, with its axis coinciding with the central axis of the first straight pipe 23, ensuring uniform water flow across the filter surface. The pore size of filter A can be designed according to actual water quality conditions, ranging from 0.2mm to 2.0mm, effectively trapping larger particles of coal slag and gravel without causing frequent clogging due to excessive fineness. Installation methods include threaded connection, clamp fixing, or welding to the support ring on the inner wall of the first straight pipe 23, ensuring it does not shift or deform under high-pressure water flow impact.

[0046] Baffle B is a ring-shaped or arc-shaped rib structure protruding from the inner wall of the first straight pipe 23, continuously or intermittently distributed along the circumference of the inner wall of the pipe. It is integrally formed or welded to the same carbon steel or stainless steel material as the first straight pipe. Its position is set at the edge of the filter screen A on the water outlet side, that is, close to the water outlet end of the first straight pipe but not immediately adjacent to the outlet, so as to play a blocking role without affecting the smooth flow of the main channel. The main task of baffle B is to provide a certain supporting force to the filter screen A when the water flow impacts it, maintaining the stability of the filter screen's working state.

[0047] The above technical solution effectively controls solid impurities in the drainage medium. Because a filter screen A is installed inside the first through pipe 23, harmful particles in the water are continuously removed, reducing the failure rate of the main drainage pump 24 and extending the equipment maintenance cycle. Simultaneously, a baffle block B is installed on the inner wall near the outlet end to ensure that filter screen A does not shift or deform under the impact of high-pressure water flow. The combined effect of these two factors ensures that the entire drainage system maintains high operational reliability even when facing high impurity content water conditions, making it particularly suitable for large water tank environments in mine return airway requiring uninterrupted drainage operations. This structure is simple and practical, requires no additional power support, is easy to maintain and clean, and has good engineering application prospects.

[0048] Filter screen A has several groups of filter control holes arranged from the center outwards; each group of filter holes has an equal diameter. By dividing the filter holes on filter screen A into multiple concentric circular filter hole groups with the center as the center, a differentiated filtration design for different areas of water flow is achieved, which not only improves the overall flow capacity of the filter screen but also enhances its anti-clogging performance. The filter hole groups are arranged radially from the inside out, forming a zoned pore size layout structure. This allows the filter screen to adapt to the flow velocity distribution characteristics of different areas while maintaining high filtration accuracy, thereby effectively alleviating the problem of localized dirt accumulation caused by uneven flow field.

[0049] Filter A is a functional component installed inside the first straight pipe 23 to intercept suspended particles and debris in the water. Its main function is to prevent larger particles from entering the main drainage pump 24, avoiding impeller wear or jamming, and ensuring long-term stable operation of the pump. Filter A can be made of stainless steel such as SUS304 or SUS316, possessing good corrosion resistance and mechanical strength, suitable for the complex working environment of humid and corrosive media in underground coal mines. Filter A has a cylindrical or flat structure, designed to fit the actual installation space and flow channel shape. It is usually fixed to the inner wall of the first straight pipe 23 or detachably installed via a flange connection, facilitating regular cleaning and maintenance.

[0050] The phrase "several filter control groups are arranged from the center outwards" should be understood as "filter hole groups," which are one or more groups of filter holes arranged in a ring around the center point of filter screen A. Each group contains multiple equally spaced through holes, forming an independent filtration unit. These filter hole groups are arranged layer by layer outwards from the center of the filter screen, forming a concentric circle structure similar to a bullseye. Figure 2 As shown, the innermost layer consists of the first filter hole group C1, the next layer consists of the second filter hole group C2, the next layer consists of the third filter hole group C3, the next layer consists of the fourth filter hole group C4, and the outermost layer consists of the fifth filter hole group C5. A certain distance is maintained between each group to ensure that the water flow in each area is independent and does not interfere with each other. This zoned structure can rationally allocate the flow area of ​​each area according to fluid mechanics principles, optimizing the overall flow field distribution.

[0051] "Equal diameter in each filter group" means that all filter holes within the same filter group have the same diameter. For example, all holes in the first filter group are Φ2mm, all holes in the second filter group are Φ3mm, all holes in the third filter group are Φ4mm, all holes in the fourth filter group are Φ5mm, and all holes in the fifth filter group are Φ6mm. This design facilitates standardized processing, improves manufacturing precision and consistency, and also facilitates quality inspection and mass production. In practice, the required hole shapes can be machined into the filter material using CNC punching, laser cutting, or die forming, ensuring uniform hole distribution and smooth, burr-free edges.

[0052] The pore size in the filter group near the center of filter screen A is smaller than that in the filter group near the outer periphery of filter screen A. In other words, the pore size in the filter group near the center of filter screen A is smaller, while the pore size in the filter group near the outer periphery is larger. This gradient pore size design is based on fluid dynamics: in the central region of the pipe, the water flow velocity is relatively low, and suspended solids easily settle; using a smaller pore size allows for fine interception. However, in the region near the pipe wall, the water flow velocity is higher, and the ability to carry impurities is strong; using a larger pore size reduces pressure loss and increases flow rate. Therefore, by dividing filter screen A into multiple filter groups with different pore size parameters and matching them with the regional flow velocity characteristics, the overall drainage efficiency can be significantly improved without excessively sacrificing filtration accuracy.

[0053] In practical implementation, guide slopes or chamfered structures can be set in the transition area between each hole group to reduce eddy current generation and improve flow pattern. In addition, the number of hole groups, number of rings, and hole diameter parameters can be flexibly adjusted according to the on-site water quality conditions. For example, in mines with high sediment content, the proportion of large peripheral hole groups can be appropriately increased, or the overall hole diameter can be reduced under clear water conditions to improve the filtration level.

[0054] The aforementioned technical features work together to optimize the structure of filter A. The overall layout of filter A determines the spatial division of the filtration area, while the concentric circular distribution of the filter pores enables a responsive design to flow field characteristics. The consistency of the internal pore diameter of each group ensures processing feasibility and product consistency, providing a fundamental support for subsequent large-scale applications.

[0055] The above technical solution achieves an improvement and upgrade to the traditional homogeneous filter structure. By dividing the filter holes on filter A into multiple groups of filter holes distributed from the center outwards, and ensuring that the internal pore diameter of each group remains consistent, differentiated filtration strategies can be implemented based on the water flow velocity characteristics of different areas. This effectively alleviates the problem of impurity accumulation caused by low flow velocity in the central area. Simultaneously, the outer high-flow-velocity area employs a larger pore diameter design, increasing the water flow capacity per unit time and reducing system energy consumption. Therefore, without significantly increasing manufacturing costs, the overall performance of the filter is improved, the equipment maintenance cycle is extended, and the continuous, efficient, and safe operation of the return airway large water tank drainage system is ensured.

Claims

1. A drainage system for a large water tank in a return airway, characterized in that, Including a high-pressure pumping pipe (10) connected to the large water tank in the return airway. The high-pressure water pumping pipe (10) is connected to the main drainage pipe (20) and the backup drainage pipe (30) respectively through the water pumping pipe tee (11). The other ends of the main drainage pipe (20) and the backup drainage pipe (30) are both connected to the main drainage pipe (40), which is connected to the coal mine drainage system pipeline. The main drainage pipeline (20) includes an inlet high-pressure pipe (22), a first straight pipe (23), a main drainage pump (24), and an outlet high-pressure pipe (25) connected in sequence. The two ends of the pumping pipe tee (11) are a loose flange and an integral flange, respectively, and the two ends of the first straight pipe (23) are a loose flange and an integral flange, respectively.

2. The drainage system for a large water tank in a return airway as described in claim 1, characterized in that, Valves are installed on both the main drainage pipe (20) and the backup drainage pipe (30).

3. The drainage system for a large water tank in a return airway as described in claim 2, characterized in that, The backup drainage pipe (30) has the same pipe connection structure as the main drainage pipe (20).

4. The drainage system for a large water tank in a return airway as described in claim 3, characterized in that, The outlet ends of the main drainage pipeline (20) and the backup drainage pipeline (30) are both connected to the drainage tee (41), and the drainage tee (41) is connected to the coal mine drainage system pipeline through the second straight pipe (42).

5. A drainage system for a large water tank in a return airway as described in any one of claims 2-4, characterized in that, A filter screen (A) is provided inside the first straight pipe (23); A baffle (B) is provided on the inner wall near the outlet end of the first straight pipe (23).

6. The drainage system for a large water tank in a return airway as described in claim 5, characterized in that, The filter screen (A) has several groups of filter control holes arranged from the center to the outer periphery; the diameter of each group of filter holes is equal.

7. A drainage system for a large water tank in a return airway as described in claim 6, characterized in that, The pore size in the filter hole group near the center of the filter screen (A) is smaller than the pore size in the filter hole group near the outer periphery of the filter screen (A).

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