A coal seam cutting gun and a coal cutting system

Abstract

The utility model relates to the technical field of coal mining, and discloses a coal seam cutting gun and a coal cutting system, the cutting gun comprises a central shaft located in the middle, an outer cover rotatable around the central shaft and located between the two end limiters and in the periphery of the central shaft, the outer cover is axially limited through the limiting assembly between the two ends, the central shaft is hollow inside and forms an inner cavity, an outer cavity is arranged between the outer cover and the central shaft, a plurality of inner holes are arranged on the wall surface of the inner cavity leading to the outer cavity, at least one pair of opposite outwardly penetrating spray holes are arranged on the outer cover, the included angle between the hole axis of the spray hole and the projection of the spray hole on the plane of the cross section of the central shaft is theta, and the included angle between the hole axis of the spray hole and the projection of the spray hole on the longitudinal symmetry plane formed by the central axis of the central shaft and the center point of the inner mouth of the spray hole is beta. The cutting gun can cut various coal seams with different dip angles, and the device can realize the characteristics that the larger the dip angle of the coal seam, the easier the coal mining.

Description

Technical Field

[0001] This utility model relates to the field of coal mining technology, and in particular to a coal seam cutting gun and a coal mining cutting system. Background Technology

[0002] The coal seam dip angle is a core parameter in coal mine geology that describes the spatial morphology of coal seams. It is defined as the angle between the coal seam bedding plane and the horizontal plane. According to the requirements of mining technology, its value range is divided into four categories: near-horizontal coal seams (below 8°), gently dipping coal seams (8° to 25°), dipping coal seams (25° to 45°), and steeply dipping coal seams (45° to 90°).

[0003] Mining inclined coal seams with large dip angles (generally 35°~90°) presents multiple technical challenges, including: limited mining space, steep working face slopes, and significant forces along the dip direction from the weight of heavy equipment such as hydraulic supports, coal mining machines, and conveyors, making them prone to overall slippage, toppling, or displacement, and increasing the difficulty of operation; personnel movement, material transportation, support work, and pillar removal all require climbing slopes, resulting in high labor intensity and low efficiency. Therefore, mining inclined coal seams with large dip angles currently presents considerable challenges, and the safety, efficiency, and convenience of coal mining urgently need improvement. Summary of the Invention

[0004] To overcome or alleviate the technical problems of safety, mining efficiency, and unmanned operation in the mining of steeply inclined coal seams, this utility model provides a coal seam cutting gun and a coal mining cutting system.

[0005] This utility model provides the following technical solution:

[0006] A coal seam cutting gun includes a central shaft located in the middle, and an outer cover rotatable around the central shaft located between two limiting components at both ends. The outer cover is axially limited at its front and rear ends by limiting components. The central shaft is hollow inside, forming an inner cavity. An outer cavity is provided between the outer cover and the central shaft. A plurality of inner holes are provided in the tube wall of the central shaft leading from the inner cavity to the outer cavity. The outer cover is provided with at least one pair of opposing outwardly penetrating nozzles. The angle between the nozzle axis and its projection on the plane containing the cross-section of the central shaft is θ. The angle between the nozzle axis and its projection on the longitudinal plane of symmetry formed by the central shaft axis and the center point of the nozzle opening is β.

[0007] According to some embodiments, when a pair of the spray holes are provided, the included angle θ ranges from 0 to 30°, and the included angle β ranges from 5 to 30°.

[0008] When there are three pairs of nozzles, the nozzle at the front end is tilted forward, the nozzle in the middle is not tilted, and the nozzle at the rear end is tilted backward. The tilt angle of the front and rear ends is 0~30°. The angle at which the nozzle at the front end is tilted forward is equal to the angle at which the nozzle at the rear end is tilted backward. The included angle β is in the range of 5~30°.

[0009] When there are two pairs of nozzles, the nozzle at the front end is tilted forward and the nozzle at the rear end is tilted backward. The tilt angle of the nozzles at both the front and rear ends is 0~30°. The angle at which the nozzle at the front end is tilted forward and the angle at which the nozzle at the rear end is tilted backward are equal. The included angle β is in the range of 5~30°.

[0010] According to some embodiments, the limiting component includes a rear limiting component fixed at a position slightly behind the central axis and a front limiting component fixed at a position slightly forward of the central axis, with the outer cover between the front limiting component and the rear limiting component. When high-pressure water is sprayed from the nozzle, the outer cover automatically rotates around the central axis.

[0011] According to some embodiments, the rear limiting assembly includes a rear limit and a first rotating base disposed between the rear limit and the outer cover; the first rotating base is connected to the rear limit by a key, and the first rotating base is rotatably connected to the outer cover by a slip ring.

[0012] According to some embodiments, the front limiting assembly includes a second rotating base, which is rotatably connected to the outer cover via a slip ring; the second rotating base is fixedly connected to the front end of the central shaft via at least two sets of fixing devices fixed in the axial and radial directions, the fixing devices being arranged at equal intervals on the diametrical plane.

[0013] According to some embodiments, the fixing device is axially fixed by a limiting cylindrical pin hole, a limiting cylindrical pin and an axial spring, and radially fixed by a radially arranged cylindrical pin hole, a cylindrical pin and a radial spring.

[0014] According to some embodiments, the sum of the cross-sectional areas of all the inner holes is greater than or equal to 1.5 times the sum of the areas of the inner openings of all the nozzles.

[0015] According to some embodiments, the nozzles are all disposed in a nozzle carrier, the nozzle carrier is disposed in an embedded hole, and the nozzle carrier is made of a material with a hardness higher than or equal to that of tungsten steel.

[0016] On the other hand, this application also provides a coal mining cutting system, which includes a coal seam cutting gun as described above, wherein a high-pressure water delivery hose, a high-pressure water delivery steel pipe and a high-pressure water pump set are connected in sequence to the rear end of the coal seam cutting gun.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The coal seam cutting gun provided by this utility model is designed for coal seams with various dip angles, especially those with large dip angles that are difficult to mine. It uses high-pressure nozzles to spray high-pressure water jets to cut the coal seam. It has the characteristic that the larger the dip angle of the coal seam, the easier it is to mine the coal. It can not only ensure high output, but also has a high level of safety. It is of great significance to realize unmanned working faces and dust-free underground coal mining. Attached Figure Description

[0019] Figure 1 A schematic diagram of the working profile of inclined coal seam strip high-pressure water jet mining provided in this embodiment of the utility model.

[0020] Figure 2 A longitudinal cross-sectional view of the coal seam cutting gun provided in an embodiment of this utility model.

[0021] Figure 3 for Figure 2 Transverse cross-sectional views of AA, BB, CC, DD, EE, FF, GG, HH, II, JJ, and KK.

[0022] Figure 4 A longitudinal cross-sectional view of the central axis of the coal seam cutting gun provided in an embodiment of this utility model.

[0023] Figure 5 A longitudinal cross-sectional view illustrating the outer cover and front and rear limiting positions of the coal seam cutting gun provided in this embodiment of the utility model.

[0024] Figure 6 A longitudinal cross-sectional view showing the outer cover with inlaid holes provided for an embodiment of this utility model.

[0025] In the picture:

[0026] Coal cutting hole 100; upper roadway 200; lower roadway 300; coal seam 400; mining strip 500;

[0027] 1. Central shaft; 2. Rear limit; 3. First rotating base; 4. Flat key; 5. Left keyway; 6. Right keyway; 7. Shaft tube wall; 8. Outer cover; 8-1. Embedded hole; 8-2. Spray hole carrier; 8-3. First spray hole 8-3-1; 8-3-2. Third spray hole 8-3-3; 8-3-4. Fifth spray hole 8-3-5. Sixth spray hole 8-3-6; 9. Slip ring; 10. Annular groove; 11. Inner cavity; 11-1, 11-2, 11-3, 11-4; 12. Second rotating base; 13. Outer cavity; 14. Cylindrical pin hole; 14-1. Cylindrical pin hole of central shaft; 15. Cylindrical pin; 15-1. Radial spring; 16. Cylindrical pin hole of limit; 17. Cylindrical pin of limit; 18. Axial spring; 19. Ejector pin hole; 20. Ejector pin; 21. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the embodiments and accompanying drawings. However, it should be understood that the embodiments and accompanying drawings are for illustrative purposes only and do not constitute any limitation on the scope of protection of the present invention. All reasonable modifications and combinations that fall within the inventive spirit of the present invention are within the scope of protection of the present invention.

[0029] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "front," and "rear," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not 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; the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In addition, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0030] The present invention will be further described below with reference to the accompanying drawings.

[0031] like Figure 1As shown, the cutting gun is suitable for the strip high-pressure water jet coal mining method. In the strip high-pressure water jet coal mining method, the coal mining face is set in the coal seam 400, and an upper roadway 200 and a lower roadway 300 are horizontally provided. Between the upper and lower roadways, there is a coal mining strip 500 along the dip of the coal seam. A coal cutting hole 100 is provided in the coal mining strip 500. A high-pressure water delivery hose that can move longitudinally is provided in the coal cutting hole. The cutting gun is installed at the lower end of the high-pressure water delivery hose.

[0032] To facilitate the construction of an intelligent coal mining system, this embodiment provides a coal seam cutting gun, which is a front-end device for coal mining, hereinafter referred to as the cutting gun.

[0033] The entire coal mining and cutting system consists of a high-pressure water pump set, a high-pressure water delivery steel pipe, a high-pressure water delivery hose, and a cutting gun. The cutting gun is located at the front end and is directly connected to the high-pressure water delivery hose. The high-pressure water delivery hose and the high-pressure water delivery steel pipe are connected in the upper roadway 200. The high-pressure water delivery steel pipe leads to the surface in a suitable manner and connects to the high-pressure water pump set located on the surface. When the high-pressure water pump set is located underground, the high-pressure water delivery steel pipe is connected to the high-pressure water pump set located underground. Before implementing high-pressure water jet coal mining, the high-pressure water delivery hose with the cutting gun fixed at the front end is... Figure 1 The upper end of the coal cutting hole 100 shown is inserted into the lower end of the coal cutting hole 100. When the valve of the high-pressure water pump group is opened, the high-pressure water will pass through the high-pressure water supply steel pipe and the high-pressure water supply hose, and finally enter the cutting gun. The cutting gun is equipped with several nozzles. When the high-pressure water is sprayed out through the nozzles, it forms a high-pressure water jet. At the same time as the high-pressure water jet is sprayed out, the cutting gun rotates automatically. The coal around the hole is broken under the high intensity and high speed impact of the high-pressure water jet and flows down the inclined coal seam floor into the chute, thereby realizing unmanned, dust-free, safe and efficient coal mining.

[0034] The main components of the cutting gun provided in this embodiment are as follows: Figure 2 As shown, the cutting gun includes a central shaft, an outer cover, and front and rear limiters. The main components include: a cylindrical central shaft 1 in the middle, an outer cover 8 covering the central shaft 1, a first rotating base 3 fixedly connected to the rear limiter 2 by a flat key, and a second rotating base 12 for fixing the limiters. The second rotating base 12 is the front limiter.

[0035] The front limit 2 of the first rotating base 3 is fixed to the central shaft 1. The annular structure protruding from the right side of the first rotating base 3 or the left side of the second rotating base 12 is a slip ring 9. The opening direction of both slip rings is towards the middle and extends into the annular groove 10 of the outer cover 8 facing outward. The two are in clearance fit. With the help of the clearance fit between the two, the outer cover 8 can rotate relative to the first rotating base 3 and the second rotating base 12.

[0036] like Figures 3-5The first rotating base 3 has a left keyway 5 in its rear limit 2 and a right keyway 6. A flat key 4 is placed in both the left and right keyways, thus connecting the rear limit 2 and the first rotating base 3 and ensuring no relative rotation occurs between them. During installation, the flat key 4 is first placed in the left keyway 5. Then, the first rotating base 3 is inserted into the central shaft 1 from the right end of the central shaft 1, and its right keyway 6 is aligned with the flat key 4. The flat key 4 is then inserted into the right keyway 6 until the rear limit 2 and the first rotating base 3 are tightly fitted together.

[0037] The protruding annular structure on the left side of the second rotating base 12 is a slip ring 9. The opening of the slip ring faces left and extends into the annular groove 10 on the right side of the outer cover 8. The two are in clearance fit. With the help of the clearance fit between the two, the outer cover 8 can rotate relative to the second rotating base 12.

[0038] There are two types of connections between the second rotating base 12 and the central shaft 1. The first type is a threaded connection, such as... Figure 1 As shown, the second type of connection is a cylindrical pin connection, as detailed below.

[0039] like Figure 4 The second rotating base 12 has a cylindrical pin hole 14, and the right side of the central shaft 1 has a radial central shaft cylindrical pin hole 14-1. When the second rotating base 12 is threadedly connected to... Figure 2 After reaching the indicated position, the cylindrical pin hole 14 of the second rotating base 12 and the cylindrical pin hole 14-1 of the central shaft are exactly coaxial. At this time, the cylindrical pin 15 and the radial spring 16 are aligned... Figure 2 The arrangement of the pins in the hole restricts the relative rotational movement of the central shaft 1 and the second rotating base 12. The radial spring 16 provides an upward elastic thrust to the cylindrical pin 15. During disassembly, when the pin 21 pushes the limiting cylindrical pin 18 through the pin hole 20 to the left side of the limiting pin hole 17, the cylindrical pin 15 will be pushed out of the cylindrical pin hole 14 by the elastic thrust of the radial spring 16. After the cylindrical pin 15 is removed, the second rotating base 12 can be rotated off the central shaft 1.

[0040] The second rotating base 12 has a limiting cylindrical pin hole 17 and a ejector pin hole 20. The diameter of the ejector pin hole 20 is much smaller than the diameter of the limiting cylindrical pin 18. The diameter of the limiting cylindrical pin hole 17 is at least 6 mm smaller than the diameter of the cylindrical pin hole 14, and the diameter of the limiting cylindrical pin 18 is at least 6 mm smaller than the diameter of the cylindrical pin 15. The cylindrical pin 15 has a limiting hole 15-1, the diameter of which is slightly larger than the diameter of the limiting cylindrical pin hole 17. When installing the cylindrical pin 15, the limiting hole 15-1 is coaxial with the limiting cylindrical pin hole 17, and the limiting cylindrical pin 18 is passed through the limiting hole 15-1 to the bottom end of the cylindrical pin hole 17, thereby fixing the second rotating base 12 to the central shaft 1. During installation, a push pin 21 needs to be inserted into the push pin hole 20 to push the right end of the limiting cylindrical pin 18 beyond the left side of the cylindrical pin hole 14. For each rotation of the second rotating base 12, the push pin 21 needs to be inserted into the push pin hole 20 to push the limiting pin 18 once, until the second rotating base 12 is installed to the desired position. Figure 2 The location shown.

[0041] After the second rotating base 12 is installed in place, the ejector pin 21 is still inserted into the ejector pin hole 20 to push the limiting cylindrical pin 18 to a position outside the left side of the cylindrical pin hole 14. Then, the radial spring 16 is first inserted into the central shaft cylindrical pin hole 14-1, and then the cylindrical pin 15 is inserted into the cylindrical pin hole 14. During the process of inserting the cylindrical pin 15, the axis of the limiting hole 15-1 is always aligned with the axis of the limiting cylindrical pin hole 17. When the axes of the two holes coincide, the ejector pin 21 is slowly moved backward. Under the elastic thrust of the axial spring 19 on the left, the limiting cylindrical pin 18 is pushed into and passes through the limiting hole 15-1 to the bottom of the limiting cylindrical pin hole 17. Thus, the second rotating base 12 is fixed together with the central shaft 1.

[0042] The cylindrical pin hole 14, the central shaft cylindrical pin hole 14-1, the cylindrical pin 15, and the radial spring 16 constitute a fixing device. Typically, at least two fixing devices are required, and these two devices are positioned at 180° intervals from each other on the diametrical plane. o Angle. Three or four sets of fixing devices can be installed. Regardless of the number of sets, each set should be arranged at equal angular intervals on the diametrical plane. Correspondingly, the number of cylindrical pin holes 17, cylindrical pins 18, axial springs 19, and ejector pin holes 20 should be increased accordingly.

[0043] The central shaft 1 is a hollow shaft, and the shaft tube wall 7 of the central shaft 1 is provided with two sets of internal holes, four in each set, as shown in the details. Figure 2 and Figure 3In the cross-sectional view along line E-E, the first inner hole 11-1, the second inner hole 11-2, the third inner hole 11-3, and the fourth inner hole 11-4, located slightly off-center within the central shaft 1, typically have axes on two mutually perpendicular diameter lines. Two holes on one diameter line and two holes on the other diameter line can be on the same diameter plane or on two different diameter planes. The function of these two sets of holes is to connect the inner cavity 11 of the central shaft with the outer cavity 13 between the cutting torch outer cover 8 and the central shaft 1, allowing high-pressure water from the inner cavity 11 to smoothly enter the outer cavity 13 between the central shaft 1 and the outer cover 8, and ultimately exit through nozzles in the outer wall of the outer cover 8, forming a high-pressure water jet. See details... Figure 2 As shown. The central shaft tube wall is usually provided with two sets of holes, but one set or three sets of holes can also be provided, but a basic principle must be followed, that is, the sum of the cross-sectional areas of all the inner holes must be greater than or equal to 1.5 times the sum of the areas of the inner openings of all the nozzles.

[0044] The outer cover 8, located around the outer perimeter of the outer cavity 13, has six inlay holes 8-1. Each inlay hole 8-1 contains a nozzle carrier 8-2, and each nozzle carrier 8-3 contains a nozzle 8-3. Figure 5 There are a total of 6 nozzles 8-3: nozzle 8-3-1, nozzle 8-3-2, nozzle 8-3-3, nozzle 8-3-4, nozzle 8-3-5, and nozzle 8-3-6. No. 8-3-1 and nozzle 8-3-2 form the first group; nozzles 8-3-3 and 8-3-4 form the second group; and nozzles 8-3-5 and 8-3-6 form the third group. These three groups are arranged at equal intervals. Each group contains two nozzles related to... Figure 2 The central axis 1 at the indicated position is symmetrical in the horizontal and longitudinal direction. The two nozzles in the first group are tilted to the right at an angle θ, with the angle θ ranging from 0 to 30 degrees. o The two nozzles in the third group are tilted to the left at an angle θ, with the angle value θ also ranging from 0 to 30 degrees. o The first group of two nozzles has the same inclination angle, and the third group of two nozzles also has the same inclination angle. The inclination angles of the two nozzles in the first and third groups are also the same, except that the inclination directions of the two nozzles in the first group are exactly opposite to those in the third group. The axes of the two nozzles in the middle of the second group are perpendicular to the central axis, and the ratio of the area of ​​the outer port cross-section to the inner port cross-section of the nozzle is 0.2:1 to 1:1.

[0045] The nozzles 8-3 are all set in nozzle carriers 8-2 made of a high-hardness material with a hardness similar to or much higher than that of tungsten steel. The nozzle carriers 8-2 are installed in the inlay holes 8-1, as detailed below. Figure 5 and Figure 6 As shown.

[0046] Typically, the outer cover 8 can be equipped with three sets of spray holes 8-3: the first set of spray holes includes the first spray hole 8-3-1 and the second spray hole 8-3-2; the second set of spray holes includes the third spray hole 8-3-3 and the fourth spray hole 8-3-4; and the third set of spray holes includes the fifth spray hole 8-3-5 and the sixth spray hole 8-3-6. See details below. Figure 5 As shown. When a higher water pressure and velocity are required, only one set of nozzles needs to be installed. This set of nozzles is located at the position of the first set of nozzles mentioned above, i.e. Figure 2 The rightmost pair of nozzles are positioned at the same angles as the aforementioned θ and β, where the included angle θ ranges from 0 to 30° and is tilted forward. Figure 2 (in the right direction), the included angle β ranges from 5 to 30°, and the tilt direction is shown in the figure. Figure 3 The K-K section in the diagram.

[0047] Each group of nozzles, in addition to having [specific features] within the longitudinal symmetry plane of the cutting gun, Figure 2 Beyond the angle shown, in Figure 3 On the cross-sectional profile (G-G section), oblique cross-sectional profile (D-D section and K-K section), each nozzle forms a specific angle β with the vertical line of symmetry of the profile, and the specific angle β ranges from 5 to 30 degrees. o The purpose of setting this angle is to automatically form a rotational couple when the high-pressure water is ejected from the nozzle, causing the outer cover 8 of the cutting gun to rotate. With the rotation of the outer cover 8, the ejected high-pressure water jet performs rotational cutting of the coal.

[0048] The number of nozzles 8-3 corresponds to the number of nozzle carriers 8-2, and the number of nozzle carriers 8-2 corresponds to the number of inlay holes 8-1.

[0049] The above embodiments are merely preferred embodiments of this utility model, and the protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are within its protection scope. It should be noted that improvements and modifications made by those skilled in the art without departing from the principle of this utility model should also be considered within its protection scope.

Claims

1. A coal seam cutting gun, characterized in that: The device includes a central shaft located in the middle, an outer cover located between two limiting components and surrounding the central shaft, which can rotate around the central shaft, with the front and rear ends of the outer cover being axially limited by the limiting components; the central shaft is hollow inside, forming an inner cavity; an outer cavity is provided between the outer cover and the central shaft; the tube wall of the central shaft leading from the inner cavity to the outer cavity has several inner holes; the outer cover has at least one pair of opposing outwardly penetrating nozzles, the angle between the nozzle's bore axis and its projection on the plane containing the cross-section of the central shaft is θ; the angle between the nozzle's bore axis and its projection on the longitudinal plane of symmetry formed by the central shaft axis and the center point of the nozzle's inner opening is β.

2. The coal seam cutting gun according to claim 1, characterized in that: When a pair of nozzles are provided, the included angle θ ranges from 0 to 30°, and the included angle β ranges from 5 to 30°. When there are three pairs of nozzles, the nozzle at the front end is tilted forward, the nozzle in the middle is not tilted, and the nozzle at the rear end is tilted backward. The tilt angle of the front and rear ends is 0~30°. The angle at which the nozzle at the front end is tilted forward is equal to the angle at which the nozzle at the rear end is tilted backward. The included angle β is in the range of 5~30°. When there are two pairs of nozzles, the nozzle at the front end is tilted forward and the nozzle at the rear end is tilted backward. The tilt angle of the nozzles at both the front and rear ends is 0~30°. The angle at which the nozzle at the front end is tilted forward and the angle at which the nozzle at the rear end is tilted backward are equal. The included angle β is in the range of 5~30°.

3. The coal seam cutting gun according to claim 2, characterized in that: The limiting assembly includes a rear limiting assembly fixed at a position slightly behind the central axis and a front limiting assembly fixed at a position slightly forward of the central axis. The outer cover is located between the front limiting assembly and the rear limiting assembly. When high-pressure water is sprayed from the nozzle, the outer cover automatically rotates around the central axis.

4. The coal seam cutting gun according to claim 3, characterized in that: The rear limiting assembly includes a rear limit and a first rotating base disposed between the rear limit and the outer cover; the first rotating base is connected to the rear limit by a key, and the first rotating base is rotatably connected to the outer cover by a slip ring.

5. The coal seam cutting gun according to claim 3 or 4, characterized in that: The front limiting assembly includes a second rotating base, which is rotatably connected to the outer cover via a slip ring; the second rotating base is fixedly connected to the front end of the central shaft via at least two sets of fixing devices fixed in the axial and radial directions, the fixing devices being arranged at equal intervals on the diametrical plane.

6. The coal seam cutting gun according to claim 5, characterized in that: The fixing device is axially fixed by a limiting cylindrical pin hole, a limiting cylindrical pin and an axial spring, and radially fixed by a cylindrical pin hole, a cylindrical pin and a radial spring.

7. The coal seam cutting gun according to claim 1, characterized in that: The sum of the cross-sectional areas of all the said inner holes is greater than or equal to 1.5 times the sum of the areas of the inner openings of all the said nozzles.

8. The coal seam cutting gun according to claim 1, characterized in that: The nozzles are all located within the nozzle carrier, which is located within the embedded hole. The nozzle carrier is made of a material with a hardness higher than or equal to that of tungsten steel.

9. A coal mining and cutting system, characterized in that: The coal seam cutting gun as described in any one of claims 1 to 8 is provided, wherein the rear end of the coal seam cutting gun is sequentially connected to a high-pressure water delivery hose, a high-pressure water delivery steel pipe, and a high-pressure water pump set.

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