A device for lowering a power casing at the bottom of a coal mine borehole

Abstract

This invention discloses a power casing lowering device for underground coal mine boreholes, including an outer pipe and a lower connector, as well as a drive shaft. The drive shaft is also equipped with a hole-sweeping drill bit and is connected to a power mechanism. The power mechanism includes a first power mechanism, multiple second power mechanisms, and a third power mechanism. The first power mechanism includes a first stator and a first rotor; the second power mechanisms include a second stator and a second rotor; and the third power mechanism includes a third stator and a third rotor. An impact mechanism is sleeved on the drive shaft, and the drive shaft is connected to the impact mechanism. This invention provides a power casing lowering device for underground coal mine boreholes, employing a multi-stage power mechanism at the bottom of the borehole to convert liquid pressure energy into mechanical energy to drive the hole-sweeping drill bit to rotate, thereby repairing irregular borehole walls and passing through collapsed borehole sections. Furthermore, the hole-sweeping drill bit has a guiding function, making it suitable for lowering casing in directional drilling with large curvature sections. Torque transmission is direct, energy loss is low, and the breaking efficiency of various components within the device is improved.

Description

Technical Field

[0001] This invention relates to the field of drilling equipment technology, specifically to a device for lowering a power casing at the bottom of a coal mine borehole. Background Technology

[0002] Drilling is a crucial technical means for gas extraction, water hazard control, and geological anomaly detection. Based on trajectory characteristics, boreholes are generally divided into three parts: the casing section, the transition section, and the target formation section. The casing section, located at the borehole opening, requires casing to be lowered for sealing. It is fundamental for ensuring large-scale borehole trajectory adjustments, controlling high-pressure water-bearing bodies and gas, and protecting fractured formations. The casing should be lowered according to design specifications and dimensions. Casing throughput capacity, casing section trajectory deviation control, and near-horizontal borehole slag removal efficiency are key factors affecting casing lowering. Current coal mine drilling technology and equipment research mainly focuses on drilling processes for the transition and target formation sections, lacking research on casing lowering equipment and supporting technologies. Furthermore, the casing section still primarily employs conventional rotary drilling, resulting in problems such as easy borehole trajectory deviation, difficulty in near-horizontal slag removal, low drilling efficiency, and frequent accidents, severely impacting the success rate of casing lowering.

[0003] Currently, casing lowering in coal mines involves manual splicing at the borehole opening and jacking down the casing using a drilling rig. Furthermore, the casing lacks a guide head at the front end. This often leads to problems during lowering, such as borehole wall deformation, localized unstable formation collapse, drill cuttings accumulation, and excessive curvature in the directional drilling trajectory, preventing the casing from reaching the target depth and rendering it useless. The method of manually splicing and jacking down the casing suffers from low success rate, low efficiency, and low safety for personnel working at height. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a device and method for lowering a power casing at the bottom of a coal mine borehole, which solves the problems that existing technologies can easily lead to the casing failing to be lowered to the target depth, low lowering efficiency, and low safety factor for personnel working at height.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a coal mine underground hole bottom power casing lowering device, including an outer pipe and a lower connector installed at one end of the outer pipe. The lower connector is a hollow structure and one end extends into the outer pipe. It also includes a drive shaft passing through the lower connector. The end of the drive shaft facing away from the outer pipe and passing through the lower connector is also equipped with a hole-sweeping drill bit.

[0006] The drive shaft, with one end facing the outer tube and extending out of the lower connector, is also connected to the power mechanism.

[0007] The power mechanism includes a first power mechanism, multiple second power mechanisms, and a third power mechanism coaxially mounted inside the outer tube.

[0008] The first power mechanism includes a first stator and a first rotor fitted inside the first stator.

[0009] The first stator includes a stator outer shell and a stator inner shell that are coaxially sleeved together. The length of the stator inner shell is shorter than that of the stator outer shell, and one end of the stator inner shell is flush with the stator inner shell.

[0010] A second helical blade is installed between the stator outer shell and the stator inner shell. Both the stator outer shell and the stator inner shell are hollow cylinders, and the center of the stator inner shell forms a fourth central through hole.

[0011] The first rotor includes a rotor center cylinder and a blade mounting cylinder installed at one end of the rotor center cylinder. A first helical blade is installed on the outer side of the blade mounting cylinder. The center of the rotor center cylinder and the blade mounting cylinder forms a third central through hole.

[0012] The rotor center cylinder is inserted into the fourth center through hole.

[0013] The inner surface of the rotor center cylinder at the end where the first helical blade is installed is provided with a spline groove, and the side of the rotor center cylinder facing away from the spline groove is connected to the drive shaft.

[0014] The second power mechanism includes a second stator and a second rotor fitted inside the second stator.

[0015] The second stator structure is the same as the first stator, and the second rotor structure is the same as the first rotor, except that a spline is provided at the end of the rotor center cylinder facing away from the rotor helical blades. The adjacent second rotors are connected to each other, and the second rotor is connected to the first rotor.

[0016] The third power mechanism includes a third stator and a third rotor fitted inside the third stator.

[0017] The third stator structure is the same as the first stator, and the third rotor structure is the same as the first rotor. The difference is that the rotor center cylinder has a spline at one end facing away from the first helical blade, and the other end of the rotor center cylinder has an internal thread section. The splined end of the third rotor is connected to the second rotor.

[0018] The outer tube is equipped with a lower connector at one end and a fixing ring at the other end. The fixing ring has a hollow structure. The other end of the third rotor is connected to the upper plug, and the upper plug passes through the fixing ring.

[0019] An impact mechanism is sleeved on the drive shaft.

[0020] The present invention also has the following technical features:

[0021] The drive shaft includes a drill bit connector, an annular boss, a main shaft, and a rotor connector that are coaxially connected in sequence.

[0022] The drill bit connector is a hollow cylinder with threads on its outer surface, which connects to the hole-sweeping drill bit.

[0023] The annular boss is a hollow cylinder with a diameter larger than that of the drill bit connector, and its outer surface contacts the inner wall of the lower connector.

[0024] The spindle is a hollow cylinder with one end open, and the internal cavity of the drill bit connector is connected. The diameter of the spindle is smaller than that of the annular boss, and the outer surface of the spindle facing away from the annular boss is threaded.

[0025] The rotor joint is a solid cylinder with a diameter smaller than that of the main shaft, and has threads on the outside, which connects to the rotor center cylinder of the first rotor.

[0026] The main shaft is provided with a water inlet hole, which connects the inside and outside of the drive shaft.

[0027] A sealing groove is provided on the outer surface of the annular boss, and a sealing ring is installed in the sealing groove.

[0028] A sealing groove is provided on the outer surface between the thread and the annular boss, and a sealing ring is installed in the sealing groove.

[0029] The main shaft is also fitted with a first bearing, and the outer ring of the first bearing contacts the inner wall of the lower connector.

[0030] The impact mechanism includes an anvil and a hammer.

[0031] The anvil includes a circular anvil base plate and multiple rising inclined surfaces installed on one side of the anvil base plate. The center of the anvil base plate forms a first central through hole, and the main shaft passes through the first central through hole and is connected to the first central through hole by threads.

[0032] The hammer includes a ring-shaped hammer body, an annular boss installed on one side of the hammer body, and multiple impact teeth installed on the other side of the hammer body. The center of the hammer body forms a second central through hole. The hammer body is sleeved on the outside of the main shaft but is not connected to the main shaft.

[0033] A spring is also installed inside the annular boss, and the other end of the spring is placed on a spring seat. The spring seat is sleeved on the outside of the rotor center cylinder of the first rotor and connected to the end face of the first stator. The spring is sleeved on the outside of the main shaft and the rotor joint.

[0034] The impact teeth are matched with the rising inclined plane and the number of impact teeth is the same as the number of rising inclined planes.

[0035] The stator housing is also provided with a rectangular boss on its outer periphery, which engages with a rectangular groove formed on the inner wall of the outer tube.

[0036] A retaining ring groove is also provided on the inner wall of the outer tube, and a retaining ring is installed in the retaining ring groove. The retaining ring is used to limit the position of the third stator.

[0037] The fixing ring includes a disc-shaped fixing ring body, a central hole opened at the center of the fixing ring body, and a plurality of water guiding holes opened along the circumference of the fixing ring body.

[0038] The upper plug includes a spherical water guide, a tooling groove, and a plug connector connected in sequence. The plug connector is connected to a third rotor, and the spherical water guide is located inside the central hole.

[0039] Thrust bearings are arranged between the first stator and the first rotor, between the second stator and the second rotor, and between the third stator and the third rotor.

[0040] A thrust bearing is also arranged between the third stator and the fixed ring.

[0041] The hole-sweeping drill bit includes a tapered drill body with a larger diameter open end and a tower-shaped groove formed inside the drill body. The inner wall of the tower-shaped groove, which is connected to the outside of the hole-sweeping drill bit, is threaded and connected to the drill bit connector.

[0042] The outer surface of the hole-sweeping drill bit is also provided with several sets of helical cutting teeth and several sets of vertical chip cutting teeth.

[0043] The drilling bit is also provided with a water outlet, which connects the tower-shaped groove and the outside of the drill bit body.

[0044] Compared with the prior art, the present invention has the following technical effects:

[0045] (I) The present invention provides a coal mine underground hole bottom power casing lowering device, which adopts a hole bottom multi-stage power mechanism to convert liquid pressure energy into mechanical energy to drive the hole sweeping drill bit to rotate, thereby repairing irregular hole walls and passing through collapsed hole sections. In addition, the hole sweeping drill bit has a guiding function and can be used to lower casing in directional drilling large curvature hole sections.

[0046] (II) The present invention provides a power casing lowering device for the bottom of a coal mine hole, wherein the turbine assembly consisting of the stator and rotor is connected to the outer tube, the rotor is connected to the stator, and the rotor is connected to each other. The installation is simple, the torque transmission between the rotors is direct, and the energy loss is low.

[0047] (III) The present invention provides a coal mine underground hole bottom power casing lowering device, wherein the rotor, stator, drive shaft and hole sweeping drill bit are all hollow structures, and the hole sweeping drill bit adopts a tower-type groove structure inside, which facilitates subsequent crushing and improves the crushing efficiency of each component inside the device.

[0048] (IV) The present invention provides a power casing lowering device for the bottom of a coal mine hole. The device is equipped with an impact mechanism, which can improve the hole sweeping efficiency of the sweeping drill bit, reduce the frictional resistance between the casing and the hole wall, and improve the casing lowering efficiency.

[0049] (V) The present invention provides a coal mine underground borehole bottom power casing lowering device. The device can be broken in the later stage by a variety of combined drilling tools and various breaking processes, which is conducive to further improving the breaking efficiency of each component inside the device. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0051] Figure 2 This is a top view of the first rotor of the present invention.

[0052] Figure 3 This is a half-sectional structural diagram of the first rotor of the present invention.

[0053] Figure 4 This is a top view of the first stator structure of the present invention.

[0054] Figure 5 This is a schematic diagram of the full cross-sectional structure of the first stator of the present invention.

[0055] Figure 6 This is a schematic diagram of the structure of the second stator of the present invention.

[0056] Figure 7 This is a schematic diagram of the structure of the third stator of the present invention.

[0057] Figure 8 This is a schematic diagram of the transmission shaft of the present invention.

[0058] Figure 9 This is a schematic diagram of the structure of the anvil of the present invention.

[0059] Figure 10 This is a half-section structural diagram of the punch of the present invention.

[0060] Figure 11 This is a schematic diagram of the structure of the impact hammer of the present invention.

[0061] Figure 12 This is a schematic diagram of the structure of the fixing ring of the present invention.

[0062] Figure 13This is a schematic diagram of the upper plug of the present invention.

[0063] Figure 14 This is a schematic diagram of the outer tube structure of the present invention.

[0064] Figure 15 This is a schematic diagram of the snap ring of the present invention.

[0065] Figure 16 This is a schematic diagram of the structure of the hole-sweeping drill bit of the present invention.

[0066] Figure 17 This is a schematic diagram illustrating the usage state of the present invention.

[0067] The meanings of the labels in the attached diagram are as follows:

[0068] 1-Outer tube, 2-Lower connector, 3-Drive shaft, 4-Sweeping drill bit, 5-Power mechanism, 6-Fixing ring, 7-Upper plug, 8-Impact mechanism, 9-Rectangular groove, 10-Snap ring groove, 11-Snap ring, 12-Thrust bearing, 13-Casing, 14-Casing fixing flange, 15-Breaking drill bit.

[0069] 3-1-Drill bit connector, 3-2-Annular boss, 3-3-Main spindle, 3-4-Rotor connector, 3-5-Water inlet hole, 3-6-Sealing groove, 3-7-First bearing.

[0070] 4-1-Drill body, 4-2-Tower-shaped groove, 4-3-Helical cutting teeth, 4-4-Vertical cutting teeth, 4-5-Water outlet.

[0071] 5-1-First power mechanism, 5-2-Second power mechanism, 5-3-Third power mechanism.

[0072] 6-1-Fixing ring body, 6-2-Center hole, 6-3-Water guide hole.

[0073] 7-1-Spherical water guide body, 7-2-Tooling trough, 7-3-Plug connector.

[0074] 8-1 Anvil, 8-2 Punch, 8-3 Spring, 8-4 Spring seat.

[0075] 5-1-1-First stator, 5-1-2-First rotor.

[0076] 5-2-1-Second stator, 5-2-2-Second rotor.

[0077] 5-3-1-Third stator, 5-3-2-Third rotor.

[0078] 8-1-1-Anvil base plate, 8-1-2-Rising slope, 8-1-3-Central through hole.

[0079] 8-2-1-Punch body, 8-2-2-Annular boss, 8-2-3-Impact tooth, 8-2-4-Punch center through hole.

[0080] 5-1-1-1-Stator outer shell, 5-1-1-2Stator inner shell, 5-1-1-3-Stator spiral blade, 5-1-1-4-Stator center through hole, 5-1-1-5-Rectangular boss.

[0081] 5-1-2-1-Rotor center cylinder, 5-1-2-2-Blade mounting cylinder, 5-1-2-3-Rotor helical blade, 5-1-2-4-Rotor center through hole, 5-1-2-5-Spline groove.

[0082] 5-2-2-6-spline.

[0083] 5-3-2-7 Internal thread section.

[0084] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0085] Unless otherwise specified, all components in this invention are components known in the prior art.

[0086] 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.

[0087] Example 1:

[0088] This embodiment provides a device for lowering a power casing at the bottom of a coal mine borehole, such as... Figures 1-7 As shown, it includes an outer tube 1 and a lower connector 2 installed at one end of the outer tube 1. The lower connector 2 is a hollow structure, with one end extending into the outer tube 1. It also includes a drive shaft 3 passing through the lower connector 2. The end of the drive shaft 3 facing away from the outer tube 1 and passing through the lower connector 2 is also equipped with a hole-sweeping drill bit 4. The end of the drive shaft 3 facing the outer tube 1 and passing through the lower connector 2 is also connected to a power mechanism 5.

[0089] The power mechanism 5 includes a first power mechanism 5-1, multiple second power mechanisms 5-2, and a third power mechanism 5-3, all coaxially mounted inside the outer tube 1.

[0090] The first power mechanism 5-1 includes a first stator 5-1-1 and a first rotor 5-1-2 sleeved inside the first stator 5-1-1.

[0091] The first stator 5-1-1 includes a stator outer shell 5-1-1-1 and a stator inner shell 5-1-1-2 that are coaxially sleeved together. The length of the stator inner shell 5-1-1-2 is shorter than that of the stator outer shell 5-1-1-1, and one end of the stator inner shell 5-1-1-2 is flush with the stator inner shell 5-1-1-2.

[0092] A stator spiral blade 5-1-1-3 is installed between the stator outer shell 5-1-1-1 and the stator inner shell 5-1-1-2. Both the stator outer shell 5-1-1-1 and the stator inner shell 5-1-1-2 are hollow cylinders. The center of the stator inner shell 5-1-1-2 forms a stator central through hole 5-1-1-4.

[0093] The first rotor 5-1-2 includes a rotor center cylinder 5-1-2-1 and a blade mounting cylinder 5-1-2-2 installed at one end of the rotor center cylinder 5-1-2-1. Rotor helical blades 5-1-2-3 are installed on the outer side of the blade mounting cylinder 5-1-2-2. The centers of the rotor center cylinder 5-1-2-1 and the blade mounting cylinder 5-1-2-2 form a rotor center through hole 5-1-2-4.

[0094] The rotor center cylinder 5-1-2-1 is inserted into the stator center through hole 5-1-1-4.

[0095] The inner surface of the rotor center cylinder 5-1-2-1, on which the rotor helical blades 5-1-2-3 are mounted, is provided with a spline groove 5-1-2-5. The side of the rotor center cylinder 5-1-2-1 facing away from the spline groove 5-1-2-5 is connected to the drive shaft 3.

[0096] The second power mechanism 5-2 includes a second stator 5-2-1 and a second rotor 5-2-2 sleeved inside the second stator 5-2-1.

[0097] The structure of the second stator 5-2-1 is exactly the same as that of the first stator 5-1-1. The structure of the second rotor 5-2-2 is basically the same as that of the first rotor 5-1-2. The difference is that a spline 5-2-2-6 is provided at one end of the rotor center cylinder 5-1-2-1 facing away from the rotor spiral blades 5-1-2-3. The adjacent second rotors 5-2-2 are connected to each other by keyway fit. The second rotor 5-2-2 and the first rotor 5-1-2 are connected by keyway fit.

[0098] The third power mechanism 5-3 includes a third stator 5-3-1 and a third rotor 5-3-2 sleeved within the third stator 5-3-1.

[0099] The structure of the third stator 5-3-1 is exactly the same as that of the second stator 5-2-1. The structure of the third rotor 5-3-2 is basically the same as that of the second rotor 5-2-2. The difference is that a spline 5-2-2-6 is provided at one end of the rotor center cylinder 5-1-2-1 facing away from the rotor helical blade 5-1-2-3. The inner surface of one end of the rotor helical blade 5-1-2-3 does not have a spline groove 5-1-2-5, but has an internal thread section 5-3-2-7 near the blade side of the rotor center through hole 5-1-2-4. The end of the third rotor 5-3-2 with the spline 5-2-2-6 is connected to the second rotor 5-2-2.

[0100] The outer tube 1 is equipped with a lower connector 2 at one end and a fixing ring 6 at the other end. The fixing ring 6 has a hollow structure. The other end of the third rotor 5-3-2 is connected to the upper plug 7. The upper plug 7 passes through the fixing ring 6.

[0101] An impact mechanism 8 is sleeved on the drive shaft 3.

[0102] The first stator 5-1-1 and the first rotor 5-1-2 constitute a turbine assembly, the second stator 5-2-1 and the second rotor 5-2-2 constitute a turbine assembly, and the third stator 5-3-1 and the third rotor 5-3-2 constitute a turbine assembly.

[0103] The first rotor 5-1-2 is a hollow structure. Its uppermost end face has a spline groove 5-1-2-5. The blade mounting cylinder 5-1-2-2 has six sets of circumferentially distributed rotor helical blades 5-1-2-3. The rotor helical blades 5-1-2-3 connect the upper and lower end faces of the upper structure of the first rotor 5-1-2. Using the upper end face as a reference surface, the helical angle of the rotor helical blades 5-1-2-3 of the first rotor 5-1-2 is 30° counterclockwise. A rotor center through hole 5-1-2-4 is provided in the middle of the first rotor 5-1-2. The rotor center through hole 5-1-2-4 makes the first rotor 5-1-2 a thin-walled structure, facilitating subsequent crushing. The first rotor 5-1-2 is connected to a rotor connector 3-4.

[0104] The first stator 5-1-1 is a cylindrical structure, including a stator housing 5-1-1-1. The stator housing 5-1-1-1 has two rectangular bosses 5-1-1-5 on its outer ring. The center of the first stator 5-1-1 is a stator center through hole 5-1-1-4. The first rotor 5-1-2 passes through the stator center through hole 5-1-1-4 and can rotate freely in the stator center through hole 5-1-1-4.

[0105] A stator helical blade 5-1-1-3 is provided between the stator housing 5-1-1-1 and the stator center through hole 5-1-1-4. The helix angle of the stator helical blade 5-1-1-3 is 30° clockwise, which is opposite to the helix angle of the rotor helical blade 5-1-2-3 of the first rotor 5-1-2. Both are equipped with thrust bearings 12, which are sleeved on the first rotor 5-1-2 and located between the lower end face of the lowest rotor and the upper end face of the first stator 5-1-1, ensuring the stability of rotor rotation and withstanding a certain axial pressure.

[0106] The first rotor 5-1-2, the second rotor 5-2-2, and the third rotor 5-3-2 are all the same size. The second rotor 5-2-2 lacks the thread for connecting to the drive shaft 3 compared to the first rotor 5-1-2, and instead has a spline 5-2-2-6. The outer contour of the spline 5-2-2-6 is consistent with the spline groove 5-1-2-5. The spline 5-2-2-6 and the spline groove 5-1-2-5 are interlocked to ensure torque transmission. The third rotor 5-3-2 lacks the spline groove 5-1-2-5 compared to the second rotor 5-2-2, and the third rotor 5-3-2 is connected to the plug 7.

[0107] As a preferred embodiment:

[0108] like Figure 8 As shown, the drive shaft 3 includes a drill bit connector 3-1, an annular boss 3-2, a main shaft 3-3, and a rotor connector 3-4, which are coaxially connected in sequence.

[0109] The drill bit connector 3-1 is a hollow cylinder with threads on its outer surface, and it is connected to the hole-sweeping drill bit 4.

[0110] The annular boss 3-2 is a hollow cylinder with a diameter larger than that of the drill bit connector 3-1, and its outer surface contacts the inner wall of the lower connector 2.

[0111] The spindle 3-3 is a hollow cylinder with one end open. Its internal cavity is connected to the internal cavity of the drill bit connector 3-1. The diameter of the spindle 3-3 is smaller than that of the annular boss 3-2. The outer surface of the spindle 3-3 facing away from the annular boss 3-2 is threaded.

[0112] The rotor joint 3-4 is a solid cylinder with a diameter smaller than that of the main shaft 3-3, and has threads on the outside, which are connected to the rotor center cylinder 5-1-2-1 of the first rotor 5-1-2.

[0113] The main shaft 3-3 is provided with a water inlet hole 3-5, which connects the inside and outside of the transmission shaft 3.

[0114] As a preferred embodiment:

[0115] A sealing groove 3-6 is provided on the outer side of the annular boss 3-2, and a sealing ring is installed in the sealing groove 3-6.

[0116] A sealing groove 3-6 is provided on the outer surface between the thread and the annular boss 3-2, and a sealing ring is installed in the sealing groove 3-6.

[0117] The main shaft 3-3 is also fitted with a first bearing 3-7, the outer ring of which is in contact with the inner wall of the lower connector 2.

[0118] The lowermost end of the drive shaft 3 is a drill bit connector 3-1, which is threadedly connected to the hole-sweeping drill bit 4. The outer ring of the annular boss 3-2 has two sealing grooves 3-6. The right side of the annular boss 3-2 is provided with a main shaft 3-3. The first bearing 3-7 is sleeved on the main shaft 3-3 and contacts the upper end face of the annular boss 3-2. The middle part of the main shaft 3-3 has two sealing grooves 3-6. The upper end of the main shaft 3-3 has a male thread section for connecting the anvil 8-1. The punch 8-2 ​​is sleeved on the main shaft 3-3. The uppermost end of the drive shaft 3 is a rotor connector 3-4. The transition section between the rotor connector 3-4 and the main shaft 3-3 has 6 circumferentially distributed water inlet holes 3-5. The lower connector 2 is sleeved on the outside of the drive shaft 3. One side of the first bearing 3-7 is pressed against the upper end face of the lower connector 2 and radially sealed by the sealing ring sleeved on the drive shaft 3 to ensure that the liquid pressure does not leak.

[0119] As a preferred embodiment:

[0120] like Figures 9-11 As shown, the impact mechanism 8 includes an anvil 8-1 and a hammer 8-2.

[0121] The anvil 8-1 includes an annular anvil base plate 8-1-1 and multiple rising inclined surfaces 8-1-2 installed on one side of the anvil base plate 8-1-1. The center of the anvil base plate 8-1-1 forms an anvil center through hole 8-1-3. The main shaft 3-3 passes through the anvil center through hole 8-1-3 and is connected to the anvil center through hole 8-1-3 by threads.

[0122] The hammer 8-2 includes a ring-shaped hammer body 8-2-1, an annular boss 8-2-2 installed on one side of the hammer body 8-2-1, and multiple impact teeth 8-2-3 installed on the other side of the hammer body 8-2-1. The center of the hammer body 8-2-1 forms a hammer center through hole 8-2-4. The hammer body 8-2-1 is sleeved on the outside of the main shaft and is not connected to the main shaft 3-3.

[0123] A spring 8-3 is also installed inside the annular boss 8-2-2. The other end of the spring 8-3 is placed on the spring seat 8-4-4. The spring seat 8-4-4 is sleeved on the outside of the rotor center cylinder 5-1-2-1 of the first rotor 5-1-2 and connected to the end face of the first stator 5-1-1. The spring 8-3 is sleeved on the outside of the main shaft 3-3 and the rotor joint 3-4.

[0124] The impact teeth 8-2-3 are matched with the rising inclined plane 8-1-2 and the number of them is the same as the number of rising inclined planes 8-1-2.

[0125] The anvil 8-1 has an overall annular structure and a central through hole 8-1-3. The central through hole 8-1-3 is provided with a female thread, which is connected to the male thread at the upper end of the main shaft 3-3. The upper surface of the anvil 8-1 is provided with four circumferentially distributed rising inclined surfaces 8-1-2. The rising angle of the inclined surfaces is 15° to 30° counterclockwise, and the lifting height is 1 to 2 cm. In this embodiment, the rising angle is 15° and the lifting height is 1 cm.

[0126] The impact hammer 8-2 has an overall annular structure with an annular boss 8-2-2 at the upper end. One end of the spring 8-3 is placed inside the annular boss 8-2-2. The impact hammer 8-2 has a central through hole 8-2-4 in the middle, and the inner diameter of the central through hole 8-2-4 is slightly larger than the outer diameter of the main shaft 3-3 to ensure that the impact hammer 8-2 can reciprocate along the main shaft 3-3. The lower end of the impact hammer has four circumferentially distributed impact teeth 8-2-3. The two sides of the impact teeth 8-2-3 are arc-shaped and 1cm high. The height of the impact teeth 8-2-3 is determined by the lifting height of the rising inclined plane 8-1-2. The other end of the spring 8-3 rests on the spring seat 8-4, which is sleeved on the first rotor 5-1-2 and located on the lower end face of the first stator 5-1-1.

[0127] Specifically, during operation, the anvil 8-1 rotates together with the drive shaft 3. The clockwise rotation of the anvil 8-1 causes the impact teeth 8-2-3 to rise to their highest point along the ascending ramp 8-1-2. At this point, the spring 8-3 is compressed and stores energy. After the impact teeth 8-2-3 pass the highest point of the ascending ramp 8-1-2, they instantly fall and impact the anvil 8-1 under the action of the spring 8-3. The anvil 8-1 rotates once, and the number of impacts is four. The impact frequency can be increased by changing the ascending ramp 501 and the number of impact teeth 8-2-3. Simultaneously, the spring stiffness, lifting height, and impact hammer mass can be adjusted to increase the impact energy.

[0128] As a preferred embodiment:

[0129] The stator housing 5-1-1-1 is also provided with a rectangular boss 5-1-1-5 on its outer periphery, and the rectangular boss 5-1-1-5 cooperates with the rectangular groove 9 opened on the inner wall of the outer tube 1.

[0130] The inner wall of the outer tube 1 is also provided with a retaining spring groove 10, and a retaining spring 11 is installed in the retaining spring groove 10. The retaining spring 11 is used to limit the position of the third stator 5-3-1.

[0131] The fixing ring 6 includes a disc-shaped fixing ring body 6-1, a central hole 6-2 opened at the center of the fixing ring body 6-1, and a plurality of water guiding holes 6-3 opened around the fixing ring body 6-1.

[0132] The upper plug 7 includes a spherical water guide body 7-1, a tooling groove 7-2, and a plug connector 7-3 connected in sequence. The plug connector 7-3 is connected to the third rotor 5-3-2, and the spherical water guide body 7-1 is located inside the central hole 6-2.

[0133] like Figures 14-15 As shown, the outer tube 1 has a male and female head structure. One end of the female head is connected to the lower connector 2, and the male head is connected to the sleeve to be lowered. One end of the male head is provided with a rectangular groove 9. The outline of the rectangular groove 9 is consistent with the outline of the rectangular boss 5-1-1-5, so that the first stator 5-1-1 can be inserted and fitted into the outer tube 1, and the first stator 5-1-1 is radially fixed and circumferentially limited. The inner side of one end of the male head is provided with a snap ring groove 10. The inner wall of the upper end of the snap ring groove 10 is provided with a female thread section. The multiple turbine sets are placed in the inner tube. The turbine set stator is axially fixed by snap ring 11, and the turbine set rotor is axially fixed by connecting and fitting with the female thread section of the outer tube 1 through the fixing ring 6.

[0134] like Figure 12 As shown, the fixing ring 6 is a disc-shaped structure. The outer ring of the fixing ring is provided with a male thread section for connecting and cooperating with the female thread section of the outer tube 1. The inner hole is slightly larger than the outer diameter of the upper plug 7, and there are 6 water guide holes 6-3 on the disc surface of the fixing ring 6.

[0135] like Figure 13 As shown, the top of the upper plug 7 is a spherical water guide 7-1, which seals the central through hole 5-1-2-4 of the rotor and diverts the liquid to the rotor spiral blades 5-1-2-3. The upper plug 7 has a tooling groove 7-2 in the middle to facilitate plug installation. The lower end of the upper plug 7 is a plug connector 7-3, which is connected to the third rotor 5-3-2.

[0136] As a preferred embodiment:

[0137] Thrust bearings 12 are arranged between the first stator 5-1-1 and the first rotor 5-1-2, between the second stator 5-2-1 and the second rotor 5-2-2, and between the third stator 5-3-1 and the third rotor 5-3-2.

[0138] A thrust bearing 12 is also arranged between the third stator 5-3-1 and the fixed ring 6.

[0139] As a preferred embodiment:

[0140] like Figure 16 As shown, the hole-sweeping drill bit 4 includes a tapered drill body 4-1 with a larger diameter and an open end, and a tower-shaped groove 4-2 formed inside the drill body 4-1. The tower-shaped groove 4-2 is connected to the drill bit 4 by threads on its inner wall at one end, which is connected to the drill bit connector 3-1.

[0141] The outer surface of the hole-sweeping drill bit 4 is also provided with several sets of spiral cutting teeth 4-3 and several sets of vertical chip cutting teeth 4-4.

[0142] The drilling bit 4 is also provided with a water outlet 4-5, which connects the tower-shaped groove 4-2 and the outside of the drill bit body 4-1.

[0143] The drill body 4-1 of the hole-sweeping drill bit 4 has an overall arc-shaped hollow structure. The front end of the drill body 4-1 is provided with 6 circumferentially distributed water outlet holes 4-5 for cooling the cutting teeth and flushing the rock cuttings in the hole. The upper end of the water outlet holes 4-5 is provided with 8 sets of spiral cutting teeth 4-3, with a spiral rise angle of 30° and 8 sets of circumferentially distributed. Each set of spiral cutting teeth 4-3 is provided with a set of vertical cutting teeth 4-4 at its upper end. The inside of the drill body 4-1 is a hollow structure, specifically a tower-shaped groove structure 4-2. The uppermost part of the inside of the drill body 4-1 is provided with a female thread. The arc-shaped structure of the drill body 4-1 plays a guiding role, ensuring that the hole-sweeping drill bit 4 can extend in the original hole. The spiral cutting teeth 4-3 are used to repair irregular hole walls. The vertical cutting teeth 4-4 are used to ensure the smoothness of the drill hole diameter and hole wall, reducing the resistance of subsequent casing lowering. The tower-shaped groove structure 4-2 facilitates subsequent crushing.

[0144] A method for using a power casing lowering device for the bottom of a coal mine borehole, such as... Figures 1 to 17 As shown, the specific steps include:

[0145] Step 1: Casing lowering procedure, following... Figure 1The bottom hole power casing lowering device is assembled and then mounted on the downhole drilling rig. The drilling rig connects 2-3 casings 13 at a time. A water feeder is installed behind the casing 13, and compressed fluid flows along the casing 13 into the bottom hole power casing lowering device, driving multiple turbine sets. Due to the spline structure between the rotors, the torque generated by the multiple turbine sets is superimposed and transmitted to the drive shaft 3. The drive shaft 3 drives the hole-sweeping drill bit 4 to rotate. Under the feed of the drilling rig, the hole-sweeping drill bit 4 grinds the irregular well wall, making the hole diameter uniform and the surface smooth. At the same time, the rotation of the drive shaft 3 drives the anvil 8-1 to rotate, thereby driving the hammer 8-2 to reciprocately impact the anvil 8-1. The impact energy is transmitted along the drive shaft to the hole-sweeping drill bit 4, improving the breaking efficiency and reducing the lowering resistance of the casing 13. The above steps are repeated until the casing 13 is lowered to the target formation.

[0146] Step 2: Device breaking step. After the casing 13 is lowered, the water supply device is removed, and the casing fixing flange 14 is installed at the end of the last casing 13. The casing fixing flange 14 is fixed to the original borehole flange of the borehole. Alternatively, the casing fixing flange 14 and the subsequent casings 13 can be grouted in the borehole annulus (using the 2-plug 1-grout method). The purpose is to fix the entire device in the borehole radially and axially. Then, the breaking drill bit 15 is lowered. The size of the breaking drill bit should be close to the inner diameter of the casing. The combination of breaking drill bits can be: (1) using a carbide drill bit with conventional drill bits to grind the components inside the bottom of the power casing lowering device until it passes through the hole sweeping drill bit 4; (2) using a PDC composite drill bit with a hydraulic impactor and conventional drill rod to impact and rotate to break the components inside the bottom of the power casing lowering device until it passes through the hole sweeping drill bit 4. When the annular water return of the entire device and the breaking drill bit combination is a mixture of coal or rock, after determining that the hole-sweeping drill bit 4 has passed through and the breaking drill bit 15 has been withdrawn, the next construction operation can be carried out.

[0147] The above technical solutions are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived by those skilled in the art within the scope of the technology disclosed in the present invention without creative effort are covered within the scope of protection of the present invention.

Claims

1. A device for lowering a power casing at the bottom of a coal mine borehole, comprising an outer pipe (1) and a lower connector (2) installed at one end of the outer pipe (1), wherein the lower connector (2) is a hollow structure and one end extends into the outer pipe (1), and further comprising a drive shaft (3) passing through the lower connector (2), wherein a hole-sweeping drill bit (4) is installed at the end of the drive shaft (3) facing away from the outer pipe (1) and extending out of the lower connector (2), characterized in that, The drive shaft (3) is also connected to the power mechanism (5) at one end, which faces the outer tube (1) and passes through the lower connector (2); The power mechanism (5) includes a first power mechanism (5-1) coaxially installed inside the outer tube (1), multiple second power mechanisms (5-2) and a third power mechanism (5-3); The first power mechanism (5-1) includes a first stator (5-1-1) and a first rotor (5-1-2) sleeved inside the first stator (5-1-1); The first stator (5-1-1) includes a stator outer shell (5-1-1-1) and a stator inner shell (5-1-1-2) that are coaxially sleeved together. The length of the stator inner shell (5-1-1-2) is shorter than that of the stator outer shell (5-1-1-1) and one end is flush with the stator inner shell (5-1-1-2). A stator spiral blade (5-1-1-3) is installed between the stator outer shell (5-1-1-1) and the stator inner shell (5-1-1-2). Both the stator outer shell (5-1-1-1) and the stator inner shell (5-1-1-2) are hollow cylinders. The center of the stator inner shell (5-1-1-2) forms a stator central through hole (5-1-1-4). The first rotor (5-1-2) includes a rotor center cylinder (5-1-2-1) and a blade mounting cylinder (5-1-2-2) installed at one end of the rotor center cylinder (5-1-2-1). Rotor helical blades (5-1-2-3) are installed on the outer side of the blade mounting cylinder (5-1-2-2). The center of the rotor center cylinder (5-1-2-1) and the blade mounting cylinder (5-1-2-2) forms a rotor center through hole (5-1-2-4). The rotor center cylinder (5-1-2-1) is inserted into the stator center through hole (5-1-1-4); The inner surface of the rotor center cylinder (5-1-2-1) on which the rotor helical blades (5-1-2-3) are mounted is provided with a spline groove (5-1-2-5), and the side of the rotor center cylinder (5-1-2-1) facing away from the spline groove (5-1-2-5) is connected to the drive shaft (3). The second power mechanism (5-2) includes a second stator (5-2-1) and a second rotor (5-2-2) sleeved within the second stator (5-2-1); The structure of the second stator (5-2-1) is the same as that of the first stator (5-1-1), and the structure of the second rotor (5-2-2) is the same as that of the first rotor (5-1-2). The difference is that a spline (5-2-2-6) is provided at one end of the rotor center cylinder (5-1-2-1) facing away from the rotor helical blades (5-1-2-3). The adjacent second rotors (5-2-2) are connected to each other, and the second rotor (5-2-2) is connected to the first rotor (5-1-2). The third power mechanism (5-3) includes a third stator (5-3-1) and a third rotor (5-3-2) sleeved within the third stator (5-3-1); The structure of the third stator (5-3-1) is the same as that of the first stator (5-1-1), and the structure of the third rotor (5-3-2) is the same as that of the first rotor (5-1-2). The difference is that the rotor center cylinder (5-1-2-1) has a spline (5-2-2-6) at one end facing away from the rotor helical blades (5-1-2-3), and the other end of the rotor center cylinder (5-1-2-1) has an internal thread section (5-3-2-7). The end of the third rotor (5-3-2) with the spline (5-2-2-6) is connected to the second rotor (5-2-2). The outer tube (1) is equipped with a lower connector (2) and a fixing ring (6) is installed at the other end. The fixing ring (6) has a hollow structure. The other end of the third rotor (5-3-2) is connected to the upper plug (7). The upper plug (7) is inserted on the fixing ring (6). An impact mechanism (8) is sleeved on the drive shaft (3).

2. The coal mine underground borehole bottom power casing lowering device as described in claim 1, characterized in that, The drive shaft (3) includes a drill bit connector (3-1), an annular boss (3-2), a main shaft (3-3), and a rotor connector (3-4) connected coaxially in sequence; The drill bit connector (3-1) is a hollow cylinder with threads on its outer surface, and is connected to the hole-sweeping drill bit (4); The annular boss (3-2) is a hollow cylinder with a diameter larger than that of the drill bit connector (3-1), and its outer surface contacts the inner wall of the lower connector (2). The spindle (3-3) is a hollow cylinder with one end open. The internal cavity of the drill bit connector (3-1) is connected. The diameter of the spindle (3-3) is smaller than that of the annular boss (3-2). The outer surface of the spindle (3-3) facing away from the annular boss (3-2) is threaded. The rotor joint (3-4) is a solid cylinder with a diameter smaller than that of the main shaft (3-3), and has threads on the outside, which connects to the rotor center cylinder (5-1-2-1) of the first rotor (5-1-2). The main shaft (3-3) is provided with a water inlet hole (3-5), which connects the inside and outside of the transmission shaft (3).

3. The coal mine underground borehole bottom power casing lowering device as described in claim 2, characterized in that, A sealing groove (3-6) is provided on the outer side of the annular boss (3-2), and a sealing ring is installed in the sealing groove (3-6); A sealing groove (3-6) is provided on the outer side of the thread and the annular boss (3-2), and a sealing ring is installed in the sealing groove (3-6); The main shaft (3-3) is also fitted with a first bearing (3-7), and the outer ring of the first bearing (3-7) contacts the inner wall of the lower connector (2).

4. The coal mine underground borehole bottom power casing lowering device as described in claim 2, characterized in that, The impact mechanism (8) includes an anvil (8-1) and a hammer (8-2); The anvil (8-1) includes an annular anvil base plate (8-1-1) and multiple rising inclined surfaces (8-1-2) installed on one side of the anvil base plate (8-1-1). The center of the anvil base plate (8-1-1) forms a central through hole (8-1-3). The main shaft (3-3) passes through the central through hole (8-1-3) and is connected to the central through hole (8-1-3) by threads. The hammer (8-2) includes an annular hammer body (8-2-1), an annular boss (8-2-2) installed on one side of the hammer body (8-2-1), and multiple impact teeth (8-2-3) installed on the other side of the hammer body (8-2-1). The center of the hammer body (8-2-1) forms a hammer center through hole (8-2-4). The hammer body (8-2-1) is sleeved on the outside of the main shaft and is not connected to the main shaft (3-3). A spring (8-3) is also installed inside the annular boss (8-2-2). The other end of the spring (8-3) is placed on the spring seat (8-4). The spring seat (8-4) is sleeved on the outside of the rotor center cylinder (5-1-2-1) of the first rotor (5-1-2) and connected to the end face of the first stator (5-1-1). The spring (8-3) is sleeved on the outside of the main shaft (3-3) and the rotor joint (3-4). The impact teeth (8-2-3) are matched with the rising inclined plane (8-1-2) and the number of them is the same as the number of rising inclined planes (8-1-2).

5. The coal mine underground borehole bottom power casing lowering device as described in claim 1, characterized in that, The stator housing (5-1-1-1) is also provided with a rectangular boss (5-1-1-5) on its outer periphery, and the rectangular boss (5-1-1-5) cooperates with the rectangular groove (9) opened on the inner wall of the outer tube (1); The outer tube (1) is also provided with a retaining ring groove (10) on its inner wall. A retaining ring (11) is installed in the retaining ring groove (10). The retaining ring (11) is used to limit the position of the third stator (5-3-1). The fixing ring (6) includes a disc-shaped fixing ring body (6-1), a central hole (6-2) opened at the center of the fixing ring body (6-1), and a plurality of water guiding holes (6-3) opened along the circumference of the fixing ring body (6-1); The upper plug (7) includes a spherical water guide (7-1), a tooling groove (7-2), and a plug connector (7-3) connected in sequence. The plug connector (7-3) is connected to the third rotor (5-3-2), and the spherical water guide (7-1) is located in the center hole (6-2).

6. The coal mine underground borehole bottom power casing lowering device as described in claim 1, characterized in that, Thrust bearings (12) are arranged between the first stator (5-1-1) and the first rotor (5-1-2), between the second stator (5-2-1) and the second rotor (5-2-2), and between the third stator (5-3-1) and the third rotor (5-3-2); A thrust bearing (12) is also arranged between the third stator (5-3-1) and the fixed ring (6).

7. The coal mine underground borehole bottom power casing lowering device as described in claim 2, characterized in that, The hole-sweeping drill bit (4) includes a tapered drill body (4-1) with a larger diameter and an open end, and a tower-shaped groove (4-2) opened in the drill body (4-1). The tower-shaped groove (4-2) has a threaded inner wall at one end that connects to the outside of the hole-sweeping drill bit (4) and is connected to the drill bit connector (3-1). The outer surface of the hole-sweeping drill bit (4) is also provided with several sets of spiral cutting teeth (4-3) and several sets of vertical chip cutting teeth (4-4); The drilling bit (4) is also provided with a water outlet (4-5), which connects the tower-shaped groove (4-2) and the outside of the drill bit body (4-1).

Images