Coal mine water pump pre-filter device

Abstract

The utility model discloses coal mine water pump prefiltering device relates to coal mine drainage technical field, it includes: water suction pipe, first filter sieve plate, second filter sieve plate, driving part is connected with second filter sieve plate, driving part is used for driving second filter sieve plate relative first filter sieve plate elevating, with cutting and clearing the coal cinder particle of being clamped in first filter sieve plate, blow-off opening, opening and closing are located one side of second filter sieve plate, and blow-off opening vertical through water suction pipe bottom setting, detection device, it includes being located first negative pressure sensor of blow-off opening one side and being located second negative pressure sensor of water pump's water suction mouth, first negative pressure sensor is used for measuring the negative pressure value of second filter sieve plate front, and second negative pressure sensor is used for measuring the negative pressure value of water pump's water suction mouth, control device. The device can remove the impurity such as a large number of coal dust coal cinder particle and sand and gravel in mine gushing water, avoid the damage and influence that pump house water pump is received during drainage.

Description

Technical Field

[0001] This utility model relates to the field of coal mine drainage technology, and more specifically, to a pre-filter device for coal mine water pumps. Background Technology

[0002] Currently, most coal mine drainage systems in my country are gradually replacing traditional manual drainage with remotely controlled intelligent drainage systems, achieving unmanned operation of underground pump rooms and ensuring safe and reliable equipment operation. The implementation of remote-controlled drainage systems in coal mines effectively improves pump utilization, extends pump motor lifespan, reduces downtime due to accidents, increases drainage capacity, and lowers coal mine production costs.

[0003] In actual drainage processes, although the pump head can filter out large pieces of coal gangue and wooden wedges, the mine water contains a large amount of coal dust, slag particles, and gravel, which causes significant problems for the pumps in the pump house during drainage, creating unreliable risks for the mine's remote-controlled drainage system.

[0004] In summary, how to remove a large amount of coal dust, slag particles, and gravel from mine water to avoid damage and impact on pumps during drainage is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide a pre-filter device for coal mine water pumps, which can remove a large amount of coal dust, coal slag particles and gravel and other impurities contained in the mine water, so as to avoid damage and impact on the pump room water pump during drainage.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A pre-filter for a coal mine water pump, located at the inlet of the coal mine water pump, includes:

[0008] A water suction pipe, one end of which is connected to a faucet, and the other end of which is used to connect to the water pump;

[0009] A first filter screen plate is disposed inside the water suction pipe to filter impurities from the sewage passing through the tap.

[0010] The second filter screen plate is attached to the side of the first filter screen plate near the head of the cage.

[0011] A driving component, which is connected to the second filter screen plate, is used to drive the second filter screen plate to rise and fall relative to the first filter screen plate in order to cut and clean the coal slag particles stuck in the first filter screen plate.

[0012] The drain outlet is located on one side of the second filter screen plate and is vertically inserted through the bottom of the suction pipe. The drain outlet is used to discharge the coal slag particles blocked by the filter from the suction pipe.

[0013] The detection device includes a first negative pressure sensor located on one side of the sewage outlet and a second negative pressure sensor located at the water inlet of the water pump. The first negative pressure sensor is used to measure the negative pressure value in front of the second filter screen plate, and the second negative pressure sensor is used to measure the negative pressure value at the water inlet of the water pump.

[0014] The control device is connected to the drive unit, the first negative pressure sensor, and the second negative pressure sensor.

[0015] In one embodiment, the other end of the suction pipe is provided with a flange for connection to the water pump.

[0016] In one embodiment, the suction pipe includes an inverted L-shaped pipe, the bottom of the vertical section of the inverted L-shaped pipe is provided with the faucet, the faucet is provided with filter holes for preliminary filtration of impurities, and the end of the horizontal section of the inverted L-shaped pipe is connected to the water pump.

[0017] In one embodiment, the horizontal section of the suction pipe is embedded with a reducer for increasing the water flow rate.

[0018] In one embodiment, the diameter of the reducing head located in the region between the first filter screen plate and the second filter screen plate is larger than the diameter of the vertical section of the water suction pipe, and the diameter of the flange end of the reducing head is the same as the diameter of the water suction pipe.

[0019] In one embodiment, the first filter screen plate comprises a stainless steel plate with a thickness greater than or equal to 8 mm.

[0020] In one embodiment, the stainless steel plate is provided with a plurality of sieve holes, the sieve holes having a diameter of less than or equal to 7 mm.

[0021] In one embodiment, the driving component includes a drive motor, a telescopic cylinder, or a lead screw and nut structure, and the moving end of the driving component is connected to the top of the second filter screen plate.

[0022] In one embodiment, an electric valve is provided at the sewage outlet, and the electric valve is connected to the control device.

[0023] In one embodiment, the drain outlet is equipped with a manually controlled on / off valve.

[0024] When using the coal mine water pump pre-filter device provided by this utility model, one end of the suction pipe can be connected to the faucet head, and the other end of the suction pipe can be connected to the water pump. Moreover, a first filter screen plate is provided inside the suction pipe, and a second filter screen plate is attached to the side of the first filter screen plate near the faucet head. The second filter screen plate is connected to the drive component, and an openable and closable drain port is provided on one side of the second filter screen plate. A first negative pressure sensor is provided on the side of the drain port near the faucet head, and a second negative pressure sensor is provided at the water pump's suction port. The drive component, the first negative pressure sensor, and the second negative pressure sensor are all connected to the control device.

[0025] When using this device to filter water, the water pump operates normally, and water flows to the pump through the suction pipe. At this time, both the first and second negative pressure sensors transmit negative pressure values ​​to the control device. The control device determines whether the negative pressure values ​​of the first and second negative pressure sensors are the same. If they are, the water pump continues to operate normally. If not, it indicates that the first filter screen of the coal mine water pump pre-filter is clogged with coal slag particles, gravel, and other debris in the sewage. In this case, the drive unit can be controlled to run for a preset time. The drive unit moves the second filter screen relative to the first filter screen, using the second filter screen to cut and clean the coal slag particles stuck in the first filter screen. After the drive unit reaches the preset time, the control device determines whether the negative pressure values ​​of the first and second negative pressure sensors are the same. If they are, the drive unit stops operating; otherwise, the drain port is opened to discharge impurities. After the impurities are discharged, the drain port is closed, and water continues to be pumped to the water pump through the suction pipe.

[0026] This application addresses the actual drainage situation in most coal mines and, considering the characteristics of water inflow in coal mine pump rooms, specifically proposes installing a pre-filter at the inlet of the coal mine water pump. Furthermore, this device reduces impurities entering the pump from wastewater, enabling true integration with remote control of the mine drainage system. While it cannot completely filter fine particles and gravel, it can filter coal slag and gravel particles clogging the screen plates and jet nozzles in the pump's jet-flow system, ensuring safe drainage in the coal mine, protecting the pumps and drainage pipelines, effectively extending the service life of drainage equipment, and guaranteeing the safe and reliable operation of the remote-controlled drainage system in the coal mine.

[0027] In summary, the pre-filter for coal mine water pumps provided by this utility model can remove a large amount of impurities such as coal dust, coal slag particles, and gravel from the mine water, thus preventing damage and impact on the pumps during drainage. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the pre-filter device for coal mine water pumps provided by this utility model.

[0030] Figure 1 middle:

[0031] 1 is the water suction pipe, 2 is the faucet, 3 is the first filter screen plate, 4 is the second filter screen plate, 5 is the driving component, 6 is the drain outlet, 7 is the detection device, 8 is the flange, and 9 is the reducer. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] The core of this utility model is to provide a pre-filter for coal mine water pumps, which can remove a large amount of coal dust, coal slag particles and gravel and other impurities from the mine water, thus preventing damage and impact on the pumps during drainage.

[0034] Please refer to Figure 1 This specific embodiment provides a pre-filter for a coal mine water pump, which is located at the inlet of the coal mine water pump and includes:

[0035] The suction pipe 1 is connected at one end to the faucet 2 and at the other end to the water pump.

[0036] The first filter screen plate 3 is installed inside the water suction pipe 1 to filter impurities from the sewage passing through the faucet 2.

[0037] The second filter screen plate 4 is attached to the side of the first filter screen plate 3 near the head 2.

[0038] The driving component 5 is connected to the second filter screen plate 4. The driving component 5 is used to drive the second filter screen plate 4 to rise and fall relative to the first filter screen plate 3 in order to cut and clean the coal slag particles stuck in the first filter screen plate 3.

[0039] The drain outlet 6 is located on one side of the second filter screen plate 4 and is vertically installed through the bottom of the suction pipe 1. The drain outlet 6 is used to discharge the coal slag particles blocked by the filter into the suction pipe 1.

[0040] The detection device 7 includes a first negative pressure sensor located on one side of the drain outlet 6 and a second negative pressure sensor located at the water pump inlet. The first negative pressure sensor is used to measure the negative pressure value in front of the second filter screen plate 4, and the second negative pressure sensor is used to measure the negative pressure value at the water pump inlet.

[0041] The control device, drive component 5, first negative pressure sensor and second negative pressure sensor are all connected to the control device.

[0042] It should be noted that the drain head 2 is used for preliminary filtration of larger diameter impurities, and the drain outlet 6 is used to discharge the coal slag particles blocked by the first filter screen 3 and the second filter screen 4. The first negative pressure sensor is used to measure the negative pressure value in front of the first filter screen 3 and the second filter screen 4 in the pre-filter device of the coal mine water pump. When the water pump is draining normally, the first negative pressure sensor and the second negative pressure sensor at the water pump suction port can be used as a reference. Once the negative pressure values ​​detected by the two are inconsistent, it indicates that the first filter screen 3 in the pre-filter device of the coal mine water pump has been blocked by coal slag particles, sand and other debris in the sewage. At this time, the operator can remotely control the drive component 5 through the control device to drive the second filter screen 4 to move up and down to cut and clean the coal slag particles and other impurities in the screen holes of the two screens so that the drainage can continue normally.

[0043] If the negative pressure values ​​detected by the first negative pressure sensor and the second negative pressure sensor are still inconsistent after the second filter screen plate 4 moves up and down to clean the impurities in the screen holes of the two screen plates, it indicates that the effect of the second filter screen plate 4 in cutting and cleaning the impurities in the screen holes of the screen plates has not met the standard. At this time, the operator can open the drain port 6 to clean the first filter screen plate 3 and the second filter screen plate 4, and discharge the coal slag particles filtered by the first filter screen plate 3 and the second filter screen plate 4. Finally, close the drain port 6 again to allow normal drainage.

[0044] By using the pre-filter for coal mine water pumps provided by this utility model, impurities entering the water pump from sewage can be reduced, truly achieving remote control operation in conjunction with the mine drainage system. Although this device cannot completely filter out fine particles and gravel, it can filter out coal slag particles and gravel that are prone to clogging the detection device 7 and the jet nozzle in the water pump jet system, ensuring safe drainage in the coal mine. It also protects the water pump, suction pipe 1, etc., greatly extending the service life of the drainage equipment and ensuring the safe and reliable operation of the remote control drainage system in the coal mine.

[0045] In practical applications, the shape, structure, size, and position of the suction pipe 1, the first filter screen plate 3, the second filter screen plate 4, the driving component 5, the drain outlet 6, the detection device 7, and the control device can be determined according to the actual situation and needs.

[0046] When using the pre-filter device for coal mine water pumps provided by this utility model, one end of the suction pipe 1 can be connected to the head 2, and the other end of the suction pipe 1 can be connected to the water pump. Moreover, a first filter screen plate 3 is provided inside the suction pipe 1, and a second filter screen plate 4 is attached to the side of the first filter screen plate 3 near the head 2. The second filter screen plate 4 is connected to the drive component 5. Furthermore, a closable drain port 6 is provided on one side of the second filter screen plate 4. A first negative pressure sensor is provided on the side of the drain port 6 near the head 2, and a second negative pressure sensor is provided at the water pump's suction port. The drive component 5, the first negative pressure sensor, and the second negative pressure sensor are all connected to the control device.

[0047] When using this device to filter water, the water pump is controlled to operate normally, and the water flows to the water pump through the suction pipe 1. At this time, both the first negative pressure sensor and the second negative pressure sensor can transmit negative pressure values ​​to the control device. The control device can determine whether the negative pressure values ​​of the first negative pressure sensor and the second negative pressure sensor are the same. If they are the same, the water pump can continue to operate normally. If not, it indicates that the first filter screen 3 of the coal mine water pump pre-filter device has been blocked by coal slag particles, gravel and other debris in the sewage. At this time, the drive component 5 can be controlled to run for a preset time. The drive component 5 drives the second filter screen 4 to rise and fall relative to the first filter screen 3, so as to use the second filter screen 4 to cut and clean the coal slag particles stuck in the first filter screen 3. After the drive component 5 reaches the preset time, the control device determines whether the negative pressure values ​​of the first negative pressure sensor and the second negative pressure sensor are the same. If they are the same, the drive component 5 is controlled to stop running. If not, the drain port 6 is opened to discharge impurities. After the impurities are discharged, the drain port 6 is closed so that the water pump can continue to be drained through the suction pipe 1.

[0048] This application addresses the actual drainage situation in most coal mines and, considering the characteristics of water inflow in coal mine pump rooms, specifically proposes installing a pre-filter at the inlet of the coal mine water pump. Furthermore, this device reduces impurities entering the pump from wastewater, enabling true integration with remote control of the mine drainage system. While it cannot completely filter fine particles and gravel, it can filter coal slag and gravel particles clogging the screen plates and jet nozzles in the pump's jet-flow system, ensuring safe drainage in the coal mine, protecting the pumps and drainage pipelines, effectively extending the service life of drainage equipment, and guaranteeing the safe and reliable operation of the remote-controlled drainage system in the coal mine.

[0049] In summary, the pre-filter for coal mine water pumps provided by this utility model can remove a large amount of impurities such as coal dust, coal slag particles, and gravel from the mine water, thus preventing damage and impact on the pumps during drainage.

[0050] In one embodiment, the other end of the suction pipe 1 is provided with a flange 8 for connection to a water pump. The diameter of the flange 8 is the same as the diameter of the water pipe connector end of the water pump, and the flange 8 and the water pipe connector end are sealed to ensure that the water flowing from the suction pipe 1 into the water pump does not leak.

[0051] In one embodiment, such as Figure 1 As shown, the suction pipe 1 includes an inverted L-shaped pipe. The bottom of the vertical section of the inverted L-shaped pipe is provided with a faucet 2. The faucet 2 is provided with a filter hole for preliminary filtration of impurities. The end of the horizontal section of the inverted L-shaped pipe is connected to a water pump.

[0052] In one embodiment, such as Figure 1 As shown, the horizontal section of the suction pipe 1 is fitted with a reducer 9 for increasing the water flow rate. The reducer 9 is used to increase the water flow rate from the pre-filter of the coal mine water pump into the pump.

[0053] In one embodiment, the diameter of the reducer 9 located in the area of ​​the first filter screen plate 3 and the second filter screen plate 4 is larger than the diameter of the vertical section of the suction pipe 1, and the diameter of the flange end of the reducer 9 is the same as the diameter of the suction pipe 1. Specifically, to ensure that the normal drainage of the suction pipe 1 is not affected after the installation of the pre-filter for the coal mine water pump, the reducer 9 is embedded in the horizontal section of the suction pipe 1. The diameter of the larger diameter end of the reducer 9 is larger than the diameter of the suction pipe 1, and the diameter of the smaller diameter end of the reducer 9 is the same as the diameter of the suction pipe 1, so as to avoid affecting the drainage flow rate of the water pump.

[0054] In one embodiment, the first filter screen 3 comprises a stainless steel plate with a thickness greater than or equal to 8 mm.

[0055] In one embodiment, the stainless steel plate is provided with a plurality of sieve holes, the sieve hole diameter being less than or equal to 7 mm.

[0056] It should be noted that the first filter screen plate 3 is used to filter impurities such as coal slag particles and gravel from the sewage flowing to the first filter screen plate 3 after passing through the faucet 2. The screen hole diameter of the first filter screen plate 3 is manufactured after multiple optimizations based on actual site conditions. The first filter screen plate 3 needs to be easy to disassemble and replace, ensuring that it can fully filter coal slag particles, gravel, and other debris from the sewage, while also ensuring that the drainage flow rate is not lower than the water flow rate before the installation of the pre-filter device for the coal mine water pump. The first filter screen plate 3 can be made of wear-resistant material, but the first filter screen plate 3 is still easily damaged by long-term collision and friction with impurities. When the detection device 7 finds that the first filter screen plate 3 is severely worn, it needs to be replaced in time.

[0057] Therefore, this application prioritizes the use of wear-resistant stainless steel to make the first filter screen plate 3. The thickness of the first filter screen plate 3 is not less than 8mm, and the aperture is less than or equal to 7mm. Due to the characteristics of coal mine water inflow, there are many impurities in coal mine wastewater. If the thickness of the first filter screen plate 3 is less than 8mm, it is easy to cause the problem of needing to replace the first filter screen plate 3 frequently, increasing the maintenance workload of operators. If the aperture of the first filter screen plate 3 is greater than 7mm, it is easy to cause the nozzles of the jet water diversion system in the drainage system to be blocked, making it impossible to achieve vacuum drainage of the water pump and affecting the safe drainage of the mine.

[0058] In one embodiment, the driving component 5 includes a drive motor, a telescopic cylinder, or a lead screw and nut structure, and the moving end of the driving component 5 is connected to the top of the second filter screen plate 4. The driving component 5 is used to drive the second filter screen plate 4 to move up and down relative to the first filter screen plate 3, so as to cut and clean the coal slag particles stuck in the first filter screen plate 3 and the second filter screen plate 4 during the water pump drainage process.

[0059] Besides using a drive motor, telescopic cylinder, or screw-nut structure to drive the second filter screen plate 4 to move up and down, a gate valve (a common type of valve used in pipeline systems to control the full opening or closing of fluids. The gate valve's opening and closing element is a gate, and the gate's movement direction is perpendicular to the fluid direction. The screw (or valve stem) of the gate valve is one of its key components, responsible for converting rotary motion into linear motion, thereby realizing the raising and lowering of the gate and controlling the opening and closing of the valve) can be used to drive the second filter screen plate 4 (equivalent to the openable and closable gate in a gate valve) to move up and down, cutting coal slag particles and other debris in the screen holes, effectively removing impurities, and ensuring the normal water flow of the suction pipe 1. Furthermore, when the control device detects a difference in negative pressure values ​​between the first and second negative pressure sensors, the control device controls the drive component 5 to operate, thereby driving the second filter screen plate 4 to move up and down relative to the first filter screen plate 3, cutting and cleaning the coal slag particles trapped in the first and second filter screen plates 3 and 4 during the water pump's drainage process.

[0060] In one embodiment, an electric valve is provided at the drain outlet 6, and the electric valve is connected to a control device. That is, the control device can remotely control the opening or closing of the drain outlet 6.

[0061] In one embodiment, a manually controlled opening and closing valve is provided at the drain outlet 6. That is, the operator can manually control the opening or closing of the drain outlet 6. If, after opening the drain outlet 6, the control device determines that the negative pressure values ​​of the first negative pressure sensor and the second negative pressure sensor are still different, it may be that one of the first filter screen plate 3 or the second filter screen plate 4 is damaged, and then the first filter screen plate 3 and the second filter screen plate 4 can be inspected and repaired.

[0062] This device breaks away from the original centrifugal pump suction pipe 1 structure and adopts a pre-filter device for coal mine water pumps to filter the sewage in suction pipe 1, effectively eliminating coal slag particles and gravel from being sucked into the pump body, reducing wear on the pump caused by impurities, and extending the pump's service life. It also ensures the safe and reliable operation of the coal mine remote control drainage system.

[0063] It should also be noted that the first negative pressure sensor and the second negative pressure sensor, the first filter screen plate 3 and the second filter screen plate 4 mentioned in this application are only distinguished by their different positions and do not have any order of precedence.

[0064] In addition, it should be noted that the orientation or positional relationship indicated by "horizontal", "vertical", etc. in this application is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the purpose of simplifying the description and making it easier to understand, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0065] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Any combination of all embodiments provided by this utility model is within the protection scope of this utility model and will not be elaborated upon here.

[0066] The pre-filter device for coal mine water pumps provided by this utility model has been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A coal mine water pump pre-filter device, which is arranged at the water inlet position of a coal mine water pump, characterized in that, include: A water suction pipe (1) is connected at one end to a faucet (2), and the other end of the water suction pipe (1) is used to connect to the water pump; The first filter screen plate (3) is disposed inside the water suction pipe (1) to filter impurities from the sewage passing through the faucet (2); The second filter screen plate (4) is attached to the side of the first filter screen plate (3) near the head (2); A drive unit (5) is connected to the second filter screen plate (4). The drive unit (5) is used to drive the second filter screen plate (4) to rise and fall relative to the first filter screen plate (3) in order to cut and clean the coal slag particles stuck in the first filter screen plate (3). The drain outlet (6) is located on one side of the second filter screen plate (4) and is vertically inserted through the bottom of the water suction pipe (1). The drain outlet (6) is used to discharge the coal slag particles blocked by the filter from the water suction pipe (1). The detection device (7) includes a first negative pressure sensor located on one side of the drain outlet (6) and a second negative pressure sensor located at the water inlet of the water pump. The first negative pressure sensor is used to measure the negative pressure value in front of the second filter screen (4), and the second negative pressure sensor is used to measure the negative pressure value at the water inlet of the water pump. The control device is connected to the drive unit (5), the first negative pressure sensor and the second negative pressure sensor.

2. The pre-filtering device for coal mine water pump according to claim 1, characterized in that, The other end of the suction pipe (1) is provided with a flange (8) for connecting to the water pump.

3. The coal mine water pump pre-filter device according to claim 1, characterized in that, The water suction pipe (1) includes an inverted L-shaped pipe. The bottom of the vertical section of the inverted L-shaped pipe is provided with the head (2). The head (2) is provided with a filter hole for preliminary filtration of impurities. The end of the horizontal section of the inverted L-shaped pipe is connected to the water pump.

4. The coal mine water pump pre-filter device according to claim 3, characterized in that, The horizontal section of the suction pipe (1) is fitted with a reducer (9) for increasing the water flow rate.

5. The coal mine water pump pre-filter device according to claim 4, characterized in that, The diameter of the reducing head (9) located in the area between the first filter screen plate (3) and the second filter screen plate (4) is larger than the diameter of the vertical section of the water suction pipe (1), and the diameter of the flange end of the reducing head (9) is the same as the diameter of the water suction pipe (1).

6. The prefiltering device for coal mine water pumps according to any one of claims 1 to 5, characterized in that, The first filter screen plate (3) includes a stainless steel plate with a thickness greater than or equal to 8 mm.

7. The coal mine water pump pre-filter device according to claim 6, characterized in that, The stainless steel plate is provided with multiple sieve holes, and the diameter of the sieve holes is less than or equal to 7 mm.

8. The prefiltering device for coal mine water pumps according to any one of claims 1 to 5, characterized in that, The drive component (5) includes a drive motor, a telescopic cylinder or a lead screw nut structure, and the moving end of the drive component (5) is connected to the top of the second filter screen plate (4).

9. The prefiltering device for coal mine water pumps according to any one of claims 1 to 5, characterized in that, An electric valve is provided at the sewage outlet (6), and the electric valve is connected to the control device.

10. The prefiltering device for coal mine water pumps according to any one of claims 1 to 5, characterized in that, The drain outlet (6) is equipped with a manually controlled opening and closing valve.

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