A hydraulic plug-type ball thrower for coal mines with a manifold and method

Abstract

The application discloses a coal mine hydraulic plug type ball thrower with a manifold and a method, which comprises a ball thrower body, a ball taking device, a hydraulic rotating mechanism and a ball storage pipe; a straight channel and a branch manifold thereof are arranged in the ball thrower body; a spherical space is arranged in the manifold; the ball taking device is arranged in the spherical space; the hydraulic rotating mechanism can drive the ball taking device to rotate; and the ball storage pipe is communicated with the spherical space, so that the ball taking device takes balls from the ball storage pipe. The application has the advantages that the influence of the ball throwing process on the pipeline pressure is greatly reduced through a double-channel design, continuous ball throwing can be realized without stopping the pressure, the volume is small, intrinsic safety can be realized, the fracturing fluid flow rate of the manifold is low, the ball taking device is less abraded, and the reliability is high.

Description

Technical Field

[0001] This invention belongs to the field of coal mine safety and relates to a ball-dropping device and method used in underground coal mine fracturing. It can be applied in fracturing conditions that require ball dropping, such as underground cementing sliding sleeve fracturing and tubing sliding sleeve fracturing. Background Technology

[0002] Ball launchers are commonly used equipment in oil, gas, and unconventional oil and gas fracturing projects. Their main function is to manually or mechanically launch balls into the manifold when temporary plugging balls are needed. Underground fracturing in coal mines is an inevitable trend in coal mine gas extraction. With the development of underground fracturing technology in coal mines, the research and development of underground ball launchers is imperative. Ball launchers used in underground coal mine fracturing, in addition to meeting high technical requirements such as minimal impact on fracturing fluid pressure and continuous ball launch capability, also need to be miniaturized and intrinsically safe. Existing ball launchers include clip-type, parallel-type, and rotary-type, etc., specifically:

[0003] (1) Magazine-type ball throwers use a principle similar to that of pistol magazines. When a ball needs to be thrown, the topmost ball is pushed into the fluid channel in sequence, making it a continuous ball thrower. The specific technical principles for throwing the ball vary. A reciprocating slider can be used to send the ball into the pipeline, or a spring-loaded ball blocker can be used to press the ball into the pipeline. However, this type of ball thrower is difficult to use in underground coal mines for the following reasons: ① It can easily affect the manifold pressure at the moment of throwing the ball; ② Most of them are electric and require Class I explosion-proof treatment. Currently, there are no products with MA certification.

[0004] (2) Parallel ball-throwing device: This device uses multiple parallel pipelines, with a temporary ball placed in each pipeline, and is controlled by two valves at the top and bottom. Its disadvantages are its large size, numerous valves, and high requirements for the hydraulic pump station if remote operation is required, resulting in high cost. Currently, the weight of a single hydraulic control plug valve can reach 180KG, and the weight of the matching hydraulic pump station can reach 0.5t. Assuming at least 5 balls are needed for single-hole ball throwing in coal mine fracturing, the complete set of hydraulic control plug valves, hydraulic pump station, and pipeline equipment can weigh more than 1t, causing great inconvenience to underground coal mine construction.

[0005] (3) The turntable ball thrower is a ball seat set on a turntable. The ball is placed on the turntable ball seat. When a ball needs to be thrown, the corresponding ball can be rotated to the throwing port for throwing. Its structure is relatively complex, and the turntable is large in size and weight, making it unsuitable for use underground.

[0006] Therefore, existing ball throwers are inconvenient to use in underground coal mines, and there is a need to develop a new remotely controllable underground pressure-stabilized continuous ball thrower. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a hydraulic rotary valve ball launcher and method for coal mines with a manifold, thereby solving problems such as pressure fluctuations in the pipeline caused by the ball launcher's insertion of temporary plugging balls into the pipeline, difficulty in continuous ball launch during fracturing without continuous pressure, large size and high cost making it inconvenient for use in underground coal mines, and intrinsic safety issues in underground coal mines.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A hydraulic rotary ball launcher for coal mines with a manifold includes a ball launcher body, a ball retriever, a hydraulic rotating mechanism, and a ball storage pipe.

[0010] The ball launcher body contains: a straight channel, a manifold, a spherical space, a rotating mechanism channel, and a ball storage tube channel; the straight channel runs through both ends of the ball launcher body to allow fracturing fluid to pass through; the manifold is a branch pipe on the side wall of the straight channel, and the inlet and outlet of the manifold are respectively connected to the straight channel; the spherical space is located on the manifold, and the diameter of the spherical space is larger than the inner diameter of the manifold; the inner diameter of the manifold between the spherical space and the manifold outlet is larger than the diameter of the temporary plug ball; the rotating mechanism channel connects the spherical space and the upper wall of the ball launcher body; the ball storage tube channel connects the spherical space and the front wall of the ball launcher body.

[0011] The ball picker is located in a spherical space. The ball picker has a spherical structure and its diameter is larger than the inner diameter of the manifold. A through hole is provided in the middle of the ball picker, and the diameter of the through hole is larger than the diameter of the temporary plugging ball.

[0012] The connecting rod of the hydraulic rotating mechanism passes through the rotating mechanism channel and is fixedly connected to the ball picker. The connecting rod is perpendicular to the through hole. The hydraulic rotating mechanism can drive the ball picker to rotate.

[0013] The ball storage tube can be installed inside the ball storage tube channel, and a temporary blocking ball can be placed inside the ball storage tube;

[0014] The ball retriever can rotate to either a ball-retrieving state or a ball-throwing state. In the ball-retrieving state, the through hole of the ball retriever is connected to the ball storage tube for ball retrieval. In the ball-throwing state, the through hole of the ball retriever is connected to the manifolds on both sides for ball throwing via the fracturing fluid diverted from the manifolds. A sealing layer is filled between the ball retriever and the spherical space to enable the ball retriever to form a dynamic seal on the manifold and ball storage tube channels, and the through hole will never connect the manifold and ball storage tube channels, thereby preventing fracturing fluid leakage.

[0015] The present invention also includes the following technical features:

[0016] Specifically, the manifold includes an upper section, a middle section, and a lower section that are connected to each other; the spherical space is located at the connection between the upper section and the middle section of the manifold; when the ball retriever is in the ball-dropping state, the fracturing fluid is injected through the straight channel and can also flow sequentially through the manifold inlet, the upper section of the manifold, the through hole of the ball retriever located in the spherical space, the middle section of the manifold, the lower section of the manifold, the manifold outlet, and the straight channel for ball dropping; when the ball retriever is in the ball-dropping state, the through hole is coaxially connected with the ball storage tube channel.

[0017] Specifically, the middle section of the manifold is parallel to the straight channel; when the ball retriever is in the throwing state, the through hole of the ball retriever is parallel to the middle section of the manifold; the ball retriever can switch to the ball retrieval state when it rotates 90 degrees horizontally from the throwing state.

[0018] Specifically, the angle between the upper section of the manifold and the straight channel is θ1, and the angle between the lower section of the manifold and the straight channel is θ2; θ1 is not greater than 65°, and θ2 is not greater than 70°.

[0019] Specifically, the diameter of the middle section of the manifold is not less than the diameter of the through hole of the ball retriever, and the diameter of the through hole of the ball retriever is not less than the inner diameter of the ball storage tube.

[0020] Specifically, the ball storage tube includes a tube body, a baffle plate, a spring, and a limiting block; one end of the tube body is open and the other end is sealed, and when the ball storage tube is inserted into the ball storage tube channel, the open end of the tube body is opposite to the ball taker; the spring and the baffle plate are located inside the tube body, one end of the spring is connected to the baffle plate, and the other end is fixed to the sealed end of the tube body, and the spring can extend and retract along the axial direction of the tube body; the limiting block is located on the side wall of the tube body and can be inserted into the tube body.

[0021] Specifically, the distance between the limiting block and the sealed end of the tube is the length of the spring in its compressed state; when multiple temporary blocking balls are sequentially inserted into the tube, they can compress the baffle and the spring. At this time, the limiting block inserted into the tube can be stuck at the front end of the baffle to limit the extension of the spring; when the limiting block is pulled out of the tube, the extension of the spring can drive the baffle to push the temporary blocking ball toward the open end of the tube, thereby entering the through hole of the ball taker.

[0022] Specifically, the hydraulic rotating mechanism includes a piston cylinder, a piston, a helical gear, and a connecting rod. The piston cylinder is mounted on the ball-collecting device body. The piston cylinder is divided into two sealed chambers by the piston head of the piston. Both sealed chambers are equipped with hydraulic nozzles, which are connected to a hydraulic pump to drive the piston to move up and down. The lower part of the piston rod extends downward out of the piston cylinder, and the lower side wall of the piston rod is provided with helical teeth. The helical teeth of the piston rod mesh with the helical gear next to it. The lower end of the helical gear is fixed to the connecting rod, so that the helical gear is driven to rotate by the up and down movement of the piston rod, thereby driving the connecting rod and the ball-collecting device connected to it to rotate.

[0023] Specifically, the hydraulic pump is an explosion-proof hydraulic pump.

[0024] The ball-throwing method of the aforementioned hydraulic rotary ball thrower for coal mines with manifold includes the following steps:

[0025] Ball storage: Multiple temporary plugging balls are sequentially loaded into the tube. The temporary plugging balls compress the spring. At this time, the limiting block is inserted into the tube and can be locked at the front end of the baffle. The ball storage tube is then loaded into the ball storage tube channel.

[0026] Ball Retrieval: The ball storage tube is inserted into the ball storage tube channel and the through hole of the ball retriever is kept coaxially connected with the ball storage tube. At this time, the limiting block on the side wall of the ball storage tube is pulled out. The spring extension can drive the baffle to push the temporarily blocked ball towards the opening end of the tube body and thus enter the through hole of the ball retriever.

[0027] Ball throwing: The hydraulic rotating mechanism drives the connecting rod to rotate 90 degrees so that the through hole of the ball retriever is connected to the manifold. The fracturing fluid flows into the spherical space from the inlet end of the manifold and pushes the temporary plugging ball into the straight channel from the outlet end of the manifold, thereby completing the ball throwing action.

[0028] The hydraulic rotating mechanism drives the connecting rod to rotate 90 degrees again so that the through hole of the ball retriever is connected to the ball storage tube, and the ball retrieval and throwing actions are repeated in sequence to complete all the throwing actions.

[0029] Compared with the prior art, the present invention has the following technical effects:

[0030] (1) The present invention uses a dual-path structure. Through the special design of the manifold, the impact of the ball throwing process on the pipeline pressure is greatly reduced. Moreover, the flow rate of the fracturing fluid in the manifold is low, resulting in less wear on the ball taker and high reliability.

[0031] (2) This invention can realize remote continuous ball throwing, avoid manual operation, and has high safety.

[0032] (3) The ball thrower of the present invention has only one action mechanism, which reduces the size and makes it easier to use in underground coal mines.

[0033] (4) The ball thrower of the present invention uses hydraulic power to realize the ball throwing action. With the help of a special explosion-proof hydraulic pump for coal mines, intrinsic safety can be achieved. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the ball-throwing device body of the present invention;

[0035] Figure 2 This is a schematic diagram of the ball retriever of the present invention in the ball-throwing state;

[0036] Figure 3 This is a schematic diagram of the ball-collecting device of the present invention in the ball-collecting state;

[0037] Figure 4 This is a schematic diagram of the interior of the ball-collecting device and the ball-throwing device of the present invention;

[0038] Figure 5This is a schematic diagram of the ball-collecting device of the present invention;

[0039] Figure 6 This is a schematic diagram of the ball storage tube of the present invention;

[0040] Figure 7 This is a schematic diagram of the ball storage tube of the present invention;

[0041] Figure 8 This is a schematic diagram of the hydraulic rotating mechanism of the present invention;

[0042] Figure 9 This is a graph showing the relationship between the angle between the upper section of the manifold and the straight channel and the fracturing fluid velocity.

[0043] Figure 10 This is a graph showing the relationship between the angle between the lower section of the manifold and the straight channel and the fracturing fluid velocity.

[0044] The meanings of the labels in the diagram are as follows:

[0045] 1. Ball thrower body; 2. Ball catcher; 3. Hydraulic rotating mechanism; 4. Ball storage tube; 11. Straight channel; 12. Manifold; 13. Spherical space; 14. Rotating mechanism channel; 15. Ball storage tube channel; 121. Upper section of manifold; 122. Middle section of manifold; 123. Lower section of manifold; 21. Through hole; 31. Piston cylinder; 32. Piston; 33. Helical gear; 34. Connecting rod; 35. Hydraulic nozzle; 41. Tube body; 42. Baffle; 43. Spring; 44. Limiting block. Detailed Implementation

[0046] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0047] Example 1:

[0048] like Figures 1 to 8 As shown, this embodiment provides a hydraulic rotary ball launcher for coal mines with a manifold, including a ball launcher body 1, a ball taker 2, a hydraulic rotating mechanism 3, and a ball storage pipe 4.

[0049] The ball launcher body 1 has the following internal structures: a straight channel 11, a manifold 12, a spherical space 13, a rotating mechanism channel 14, and a ball storage pipe channel 15. The straight channel 11 runs through both ends of the ball launcher body 1 to allow fracturing fluid to pass through. The manifold 12 is a branch pipe on the side wall of the straight channel 11, and the inlet and outlet of the manifold 12 are respectively connected to the straight channel 11. The spherical space 13 is located on the manifold 12, and the diameter of the spherical space 13 is larger than the inner diameter of the manifold 12. The inner diameter of the manifold 12 between the spherical space 13 and the outlet of the manifold 12 is larger than the diameter of the temporary plug ball. The rotating mechanism channel 14 connects the spherical space 13 and the upper wall of the ball launcher body 1. The ball storage pipe channel 15 connects the spherical space 13 and the front wall of the ball launcher body 1.

[0050] The ball taker 2 is located in the spherical space 13. The ball taker 2 has a spherical structure and its diameter is larger than the inner diameter of the manifold 12. A through hole 21 is provided in the middle of the ball taker 2. The diameter of the through hole 21 is larger than the diameter of the temporary plug ball.

[0051] The connecting rod 34 of the hydraulic rotating mechanism 3 passes through the rotating mechanism channel 14 and is fixedly connected to the ball picker 2. The connecting rod 34 is perpendicular to the through hole 21. The hydraulic rotating mechanism 3 can drive the ball picker 2 to rotate.

[0052] The ball storage tube 4 can be installed inside the ball storage tube channel 15, and a temporary blocking ball can be placed inside the ball storage tube 4.

[0053] The ball retriever 2 can rotate to either the ball retrieval state or the ball throwing state. In the ball retrieval state, the through hole 21 of the ball retriever 2 is connected to the ball storage tube 4 to retrieve the ball. In the ball throwing state, the through hole 21 of the ball retriever 2 is connected to the manifolds 12 on both sides to throw the ball through the fracturing fluid diverted from the manifolds 12. A sealing layer is filled between the ball retriever 2 and the spherical space 13 so that the ball retriever 2 can form a dynamic seal on the manifolds 12 and the ball storage tube channel 15, and the through hole 21 will never connect the manifolds 12 and the ball storage tube channel 15, thereby preventing fracturing fluid leakage.

[0054] In this embodiment, the manifold 12 includes an upper manifold section 121, a middle manifold section 122, and a lower manifold section 123 that are connected to each other; the spherical space 13 is located at the connection between the upper manifold section 121 and the middle manifold section 122; when the ball taker 2 is in the ball throwing state, the fracturing fluid is injected through the straight channel 11 and can also flow sequentially through the manifold inlet, the upper manifold section 121, the through hole 21 of the ball taker 2 located in the spherical space 13, the middle manifold section 122, the lower manifold section 123, the manifold outlet, and the straight channel 11 to throw the ball; when the ball taker 2 is in the ball taking state, the through hole 21 is coaxially connected with the ball storage tube channel 15.

[0055] The middle section 122 of the manifold is parallel to the straight channel 11; when the ball retriever 2 is in the throwing state, the through hole 21 of the ball retriever 2 is parallel to the middle section 122 of the manifold, and the connection between the upper section of the manifold and the spherical space, as well as the connection between the middle section of the manifold and the spherical space, are all connected to the through hole; when the ball retriever 2 rotates horizontally by 90 degrees from the throwing state, it can switch to the ball retrieval state, at which time the through hole is coaxially connected to the ball storage tube channel.

[0056] The angle between the upper section 121 of the manifold and the straight channel 11 is θ1, and the angle between the lower section 123 of the manifold and the straight channel 11 is θ2; θ1 is not greater than 65°, and θ2 is not greater than 70°. For details, see attached... Figure 9The left figure shows the fluid velocity contour plots between the upper section of the manifold and the straight channel at different angles, while the right figure shows the relationship between the angle between the upper section of the manifold and the straight channel and the fracturing fluid velocity. It can be seen from the figures that when θ1 ≤ 65°, the fluid velocity can reach at least 0.2, which is beneficial for fracturing fluid ball deployment. More preferably, considering the optimization of fluid velocity and manifold length (i.e., the overall size of the device), in this embodiment, when θ1 is 65°, it can both meet the ball deployment requirements for fluid velocity and ensure that the upper section of the manifold is not too long. Similarly, specifically, see the appendix... Figure 10 In the diagram, the left figure shows the flow velocity cloud map of the fluid passing through the lower section of the manifold and the straight channel at different angles, and the right figure shows the relationship between the angle between the lower section of the manifold and the straight channel and the fracturing fluid velocity. It can be seen from the figure that when θ2≤70°, the fluid velocity can reach no less than 0.01, which is beneficial for fracturing fluid ball dropping. More preferably, considering the optimization of fluid velocity and manifold length, i.e., the overall size of the device, in this embodiment, when θ2 is 70°, it can not only meet the ball dropping requirements for fluid velocity, but also ensure that the length of the lower section of the manifold is not too long.

[0057] The diameter of the middle section 122 of the manifold is not less than the diameter of the through hole 21 of the ball picker 2, and the diameter of the through hole 21 of the ball picker 2 is not less than the inner diameter of the ball storage tube 4.

[0058] The ball storage tube 4 includes a tube body 41, a baffle 42, a spring 43, and a limiting block 44. One end of the tube body 41 is open and the other end is sealed. When the ball storage tube 4 is inserted into the ball storage tube channel 15, the open end of the tube body 41 is opposite to the ball taker 2. In this embodiment, the ball storage tube is threadedly connected to the ball storage tube channel. The spring 43 and the baffle 42 are located inside the tube body 41. One end of the spring 43 is connected to the baffle 42, and the other end is fixed to the sealed end of the tube body 41. The spring 43 can extend and retract along the axial direction of the tube body 41. The limiting block 44 is located on the side wall of the tube body 41 and can be inserted into the tube body 41.

[0059] The distance between the limiting block 44 and the sealing end of the tube body 41 is the length of the spring 43 in its compressed state; for example Figure 6 As shown, when multiple temporary blocking balls are sequentially inserted into the tube 41, they can compress the baffle 42 and the spring 43. At this time, the limiting block 44 is inserted into the tube 41 and can be locked at the front end of the baffle 42 to limit the extension of the spring 43; as Figure 7 As shown, when the limiting block 44 is pulled out of the tube 41, the spring 43 extends and drives the baffle 42 to push the temporarily blocked ball toward the opening end of the tube 41, thereby entering the through hole 21 of the ball taker 2.

[0060] The hydraulic rotating mechanism 3 includes a piston cylinder 31, a piston 32, a helical gear 33, and a connecting rod 34. The piston cylinder 31 is mounted on the ball-throwing device body 1. The piston cylinder 31 is divided into two sealed chambers by the piston head of the piston 32. Both sealed chambers are equipped with hydraulic nozzles 35, which are connected to a hydraulic pump to drive the piston 32 to move up and down. The lower part of the piston rod of the piston 32 extends downward out of the piston cylinder 31, and the lower side wall of the piston rod is provided with helical teeth. The helical teeth of the piston rod mesh with the helical gear 33 next to it. The lower end of the helical gear 33 is fixed to the connecting rod 34 so that the helical gear 33 can be driven to rotate by the up and down movement of the piston rod, thereby driving the connecting rod 34 and the ball-retrieving device 2 connected to it to rotate.

[0061] The hydraulic pump is an explosion-proof hydraulic pump to achieve intrinsic safety.

[0062] In this embodiment, as Figure 4 As shown in the top view of the ball retriever in the spherical space, the four corners of the ball retriever's through hole are points A, B, C, and D, respectively; the upper end point of the upper manifold section where it connects with the spherical space is E, and the lower end point is F; the left end point of the storage tube channel where it connects with the spherical space is G, and the right end point is H; the lower end point of the middle manifold section where it connects with the spherical space is I, and the upper end point is J. When the ball retriever is in the throwing state, point A is close to point E and above point E, point B is between point F and point G, point C is level with or slightly lower than point J, and point D is level with or slightly higher than point I. If the ball retriever is rotated 90 degrees counterclockwise and is in the ball-retrieving state, point A is level with or slightly to the right of point G, and point B is level with or slightly to the left of point H. If the ball retriever is rotated 90 degrees clockwise and is in the ball-retrieving state, point I is level with or slightly to the right of point G, and point J is level with or slightly to the left of point H.

[0063] If the ball retriever rotates 90 degrees counterclockwise from the throwing position to the ball retrieving position, then the following must be satisfied:

[0064] The length of the line connecting AB is less than the length of the straight line FG to prevent the upper section of the manifold from connecting with the gas storage tube; and when point D turns to point J, point B has not yet reached point G to prevent the middle section of the manifold from connecting with the gas storage tube.

[0065] If the ball retriever rotates 90 degrees clockwise from the throwing position to the retrieval position, then the following conditions must be met:

[0066] The length of the CD line is less than the length of the HI line to prevent the middle section of the manifold from connecting with the gas storage tube; and when point B turns to point E, point D has not yet reached point H to prevent the upper section of the manifold from connecting with the gas storage tube.

[0067] More specifically, in this embodiment, the ball-throwing device body is a cuboid made of high-strength wear-resistant alloy material, with a length × width × height of 1m × 0.5m × 0.3m. The diameter of the straight channel is 70mm; the diameter of the upper section of the manifold is 10mm; and the diameters of the middle and lower sections of the manifold are 70mm. The diameter of the spherical space is 90mm, the diameter of the ball-collecting device is 88mm, and the diameter of the through hole is 60mm. The gap between the spherical space and the ball-collecting device is filled with polytetrafluoroethylene (PTFE); the inner diameter of the ball storage device is 60mm. The entire ball-throwing device system uses hydraulic transmission for remote control, improving safety.

[0068] Example 2:

[0069] This embodiment provides a ball-throwing method for a hydraulic rotary ball thrower for coal mines with a manifold, including the following steps:

[0070] Ball storage: Multiple temporary plugging balls are sequentially loaded into the tube. The temporary plugging balls compress the spring. At this time, the limiting block is inserted into the tube and can be locked at the front end of the baffle. The ball storage tube is then loaded into the ball storage tube channel.

[0071] Ball Retrieval: The ball storage tube is inserted into the ball storage tube channel and the through hole of the ball retriever is kept coaxially connected with the ball storage tube. At this time, the limiting block on the side wall of the ball storage tube is pulled out. The spring extension can drive the baffle to push the temporarily blocked ball towards the opening end of the tube body and thus enter the through hole of the ball retriever.

[0072] Ball throwing: The hydraulic rotating mechanism drives the connecting rod to rotate 90 degrees so that the through hole of the ball retriever is connected to the manifold. The fracturing fluid flows into the spherical space from the inlet end of the manifold and pushes the temporary plugging ball into the straight channel from the outlet end of the manifold, thereby completing the ball throwing action.

[0073] The hydraulic rotating mechanism drives the connecting rod to rotate 90 degrees again so that the through hole of the ball retriever is connected to the ball storage tube, and the ball retrieval and throwing actions are repeated in sequence to complete all the throwing actions.

Claims

1. A hydraulic rotary ball launcher for coal mines with a manifold, characterized in that, It includes a ball-throwing device (1), a ball-retrieving device (2), a hydraulic rotating mechanism (3), and a ball-storage tube (4). The ball launcher body (1) contains: a straight channel (11), a manifold (12), a spherical space (13), a rotating mechanism channel (14), and a ball storage tube channel (15); the straight channel (11) runs through the left and right ends of the ball launcher body (1) to allow fracturing fluid to pass through; the manifold (12) is a branch pipe on the side wall of the straight channel (11), and the inlet and outlet of the manifold (12) are respectively connected to the straight channel (11); the spherical space (13) is located on the manifold (12), and the diameter of the spherical space (13) is larger than the inner diameter of the manifold (12); the inner diameter of the manifold (12) between the spherical space (13) and the outlet of the manifold (12) is larger than the diameter of the temporary plug ball; the rotating mechanism channel (14) connects the spherical space (13) and the upper wall of the ball launcher body (1); the ball storage tube channel (15) connects the spherical space (13) and the front wall of the ball launcher body (1); The ball taker (2) is located in the spherical space (13). The ball taker (2) has a spherical structure and its diameter is larger than the inner diameter of the manifold (12). A through hole (21) is provided in the middle of the ball taker (2), and the diameter of the through hole (21) is larger than the diameter of the temporary plug ball. The connecting rod (34) of the hydraulic rotating mechanism (3) passes through the rotating mechanism channel (14) and is fixedly connected to the ball picker (2). The connecting rod (34) is perpendicular to the through hole (21). The hydraulic rotating mechanism (3) can drive the ball picker (2) to rotate. The ball storage tube (4) can be installed in the ball storage tube channel (15) and a temporary blocking ball can be placed in the ball storage tube (4); The ball retriever (2) can rotate to either the ball retrieval state or the ball throwing state. In the ball retrieval state, the through hole (21) of the ball retriever (2) is connected to the ball storage tube (4) to retrieve the ball. In the ball throwing state, the through hole (21) of the ball retriever (2) is connected to the manifolds (12) on both sides to throw the ball using the fracturing fluid diverted from the manifolds (12). A sealing layer is filled between the ball retriever (2) and the spherical space (13) so that the ball retriever (2) can form a dynamic seal on the manifold (12) and the ball storage tube channel (15), and the through hole (21) will never connect the manifold (12) and the ball storage tube channel (15), thereby preventing fracturing fluid leakage. The manifold (12) includes an upper section (121), a middle section (122), and a lower section (123) that are connected. The spherical space (13) is located at the connection between the upper section (121) and the middle section (122). When the ball taker (2) is in the ball-throwing state, the fracturing fluid is injected through the straight channel (11) and can also flow sequentially through the manifold inlet, the upper section (121), the through hole (21) of the ball taker (2) located in the spherical space (13), the middle section (122), the lower section (123), the manifold outlet, and the straight channel (11) to throw the ball. When the ball taker (2) is in the ball-throwing state, the through hole (21) is coaxially connected with the ball storage tube channel (15). The ball storage tube (4) includes a tube body (41), a baffle (42), a spring (43), and a limiting block (44); one end of the tube body (41) is open and the other end is sealed. When the ball storage tube (4) is inserted into the ball storage tube channel (15), the open end of the tube body (41) is opposite to the ball taker (2); the spring (43) and the baffle (42) are located inside the tube body (41). One end of the spring (43) is connected to the baffle (42), and the other end is fixed to the sealed end of the tube body (41). The spring (43) can extend and retract along the axial direction of the tube body (41); the limiting block (44) is located on the side wall of the tube body (41) and can be inserted into the tube body (41); The hydraulic rotating mechanism (3) includes a piston cylinder (31), a piston (32), a helical gear (33), and a connecting rod (34). The piston cylinder (31) is located on the body (1) of the ball thrower. The piston cylinder (31) is divided into two sealed chambers by the piston head of the piston (32). Both sealed chambers are equipped with hydraulic nozzles (35). The hydraulic nozzles (35) are connected to a hydraulic pump to drive the piston (32) to move up and down. The lower part of the piston rod of the piston (32) extends downward out of the piston cylinder (31), and the lower side wall of the piston rod is provided with helical teeth. The helical teeth of the piston rod mesh with the helical gear (33) next to it. The lower end of the helical gear (33) is fixed to the connecting rod (34) so ​​that the helical gear (33) can be driven to rotate by the up and down movement of the piston rod, thereby driving the connecting rod (34) and the ball taker (2) connected to it to rotate.

2. The hydraulic rotary ball launcher for coal mines with a manifold as described in claim 1, characterized in that, The middle section (122) of the manifold is parallel to the straight channel (11); when the ball retriever (2) is in the throwing state, the through hole (21) of the ball retriever (2) is parallel to the middle section (122) of the manifold; the ball retriever (2) can switch to the ball retrieval state when it rotates 90 degrees horizontally from the throwing state.

3. The hydraulic rotary ball launcher for coal mines with a manifold as described in claim 2, characterized in that, The angle between the upper section (121) of the manifold and the straight channel (11) is θ1, and the angle between the lower section (123) of the manifold and the straight channel (11) is θ2; θ1 is not greater than 65°, and θ2 is not greater than 70°.

4. The hydraulic rotary ball launcher for coal mines with a manifold as described in claim 1, characterized in that, The diameter of the middle section (122) of the manifold is not less than the diameter of the through hole (21) of the ball taker (2), and the diameter of the through hole (21) of the ball taker (2) is not less than the inner diameter of the ball storage tube (4).

5. The hydraulic rotary ball launcher for coal mines with a manifold as described in claim 1, characterized in that, The distance between the limiting block (44) and the sealed end of the tube (41) is the length of the spring (43) in its compressed state. When multiple temporary blocking balls are inserted into the tube (41) in sequence, they can compress the baffle (42) and the spring (43). At this time, the limiting block (44) inserted into the tube (41) can be stuck at the front end of the baffle (42) to limit the extension of the spring (43). When the limiting block (44) is pulled out of the tube (41), the extension of the spring (43) can drive the baffle (42) to push the temporary blocking ball to the open end of the tube (41) and thus enter the through hole (21) of the ball taker (2).

6. The hydraulic rotary ball launcher for coal mines with a manifold as described in claim 1, characterized in that, The hydraulic pump is an explosion-proof hydraulic pump.

7. The ball-throwing method of the hydraulic rotary ball thrower for coal mines with manifold as described in claim 5, characterized in that, Includes the following steps: Ball storage: Multiple temporary plugging balls are sequentially loaded into the tube. The temporary plugging balls compress the spring. At this time, the limiting block is inserted into the tube and can be locked at the front end of the baffle. The ball storage tube is then loaded into the ball storage tube channel. Ball Retrieval: The ball storage tube is inserted into the ball storage tube channel and the through hole of the ball retriever is kept coaxially connected with the ball storage tube. At this time, the limiting block on the side wall of the ball storage tube is pulled out. The spring extension can drive the baffle to push the temporarily blocked ball towards the opening end of the tube body and thus enter the through hole of the ball retriever. Ball throwing: The hydraulic rotating mechanism drives the connecting rod to rotate 90 degrees so that the through hole of the ball retriever is connected to the manifold. The fracturing fluid flows into the spherical space from the inlet end of the manifold and pushes the temporary plugging ball into the straight channel from the outlet end of the manifold, thereby completing the ball throwing action. The hydraulic rotating mechanism drives the connecting rod to rotate 90 degrees again so that the through hole of the ball retriever is connected to the ball storage tube, and the ball retrieval and throwing actions are repeated in sequence to complete all the throwing actions.

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