Mining magnetic attraction butt joint type fishing tool and using method

Abstract

The invention discloses a mining magnetic attraction butt-joint type fishing tool and a using method. The mining magnetic attraction butt-joint type fishing tool comprises a male tap, a female connecting plug, a universal head, a connecting rod, a centralizing spring, a telescopic sensor and a sealing rubber sleeve. The front section of the male tap is a tap section, and the rear section is a male connector; the outer layer of the conical section is a neodymium iron boron magnet material layer; the male tap is provided with a Y-shaped channel; a positioning tooth groove is formed in the outer wall of the male connecting plug; the rear part of the female connecting plug can be connected with a drill rod; positioning groove teeth are distributed on the inner wall of the inserting groove, and after the male inserting connector and the female inserting connector are connected in an inserting mode, the positioning tooth grooves and the positioning groove teeth are meshed to achieve locking so as to transmit torque and axial force; the female connecting plug is provided with a Y-shaped channel; the universal head is arranged in the inserting groove, the front end of the universal head is connected with the centralizing spring, the centralizing spring is connected with the male inserting head, and the telescopic sensor is arranged in the centralizing spring; and the sealing rubber sleeve is connected with the male connecting plug and the female connecting plug in a surrounding manner. By the adoption of the magnetic attraction butt joint principle, the butt joint accuracy of the fishing tool and the fish in the hole is improved, and then the fishing efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of coal mine gas extraction technology, and relates to a magnetic docking retrieval tool for mining and its usage method. Background Technology

[0002] Coal mine gas drainage is a crucial means of preventing gas exceedances, and drilling for gas drainage is the primary form of coal mine gas control. During drilling operations, accidents frequently occur due to factors such as complex geological formations causing drill bit burial, drill string wear, worker error, and inherent quality issues with the drilling tools. Minor accidents may result in ordinary drill bits becoming stuck in the borehole, causing tens of thousands of yuan in economic losses; more serious accidents may involve directional drilling tools, measurement systems, and screw motors becoming stuck in the hole, causing hundreds of thousands of yuan in economic losses. Furthermore, these accidents impact the drilling schedule, delaying gas drainage projects and severely affecting roadway excavation and coal seam recovery.

[0003] Currently, the common method for retrieving broken drill bits in boreholes is to use a male (female) cone retrieval system. This involves attaching a male (female) cone to the front end of the drill rod, lowering it to a designated position, and then docking it with the fish that has fallen into the borehole. After docking, rotational pressure is used to create a fishing line for the fish. Once the line is successfully created, the drill string is pulled out to retrieve the fish. However, because this method uses a rigid connection between the male (female) cone and the drill rod, it is difficult to achieve precise docking at the broken drill bit location in actual operation. In other words, this method generally suffers from limitations in docking efficiency and low retrieval success rate. Therefore, it is necessary to research a retrieval method that overcomes these limitations, improves the docking efficiency of the male (female) cone with the fish that has fallen into the borehole, and thus improves the overall success rate of the retrieval operation. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a magnetic docking salvage tool for mining and its usage method, so as to solve the problems of insufficient docking accuracy and low salvage success rate of current salvage tools.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A magnetic docking salvage tool for mining includes a male cone, a female connector, a universal joint, a connecting rod, a straightening spring, a telescopic sensor, and a sealing sleeve. The male cone has a conical section at the front, a middle section at the middle, and a male connector at the rear. The outer layer of the conical section is a neodymium iron boron magnet material layer, which is tightly bonded to the internal material and has threads on the outer layer to allow the drill bit to be threaded into the hole after successful docking. The male cone has a water flow channel at its center, which branches into a Y-shaped channel at the male connector. The male connector has circumferentially distributed positioning grooves on its outer wall. The female connector has a groove at the front and can be connected to the drill pipe at the rear; the groove can accommodate the axial insertion of the male connector; positioning teeth are evenly distributed circumferentially on the inner sidewall of the groove, and correspond one-to-one with the positioning teeth of the male connector. After the male connector and the female connector are inserted, the positioning teeth mesh with each other to lock and transmit torque and axial force; the female connector has a water flow channel at the center and splits forward into a Y-shaped channel, which corresponds to the Y-shaped channel of the male connector; The universal joint is located in the center of the bottom of the insertion slot. The front end of the universal joint is connected to the centering spring via a connecting rod. The front end of the centering spring is connected to the center of the rear end of the male connector. A telescopic sensor is installed inside the centering spring. The tolerance connector is covered with a sealing sleeve. The front end of the sealing sleeve is circumferentially connected to the outer wall of the front end of the tolerance connector, and the rear end of the sealing sleeve is circumferentially connected to the front end of the female connector.

[0006] The present invention also includes the following technical features: Specifically, each of the male and female connectors is provided with a Y-shaped channel to form a double Y-shaped water eye with a diameter of 20mm. It is equipped with a BLY390 mud pump truck and uses a medium pumping rate of 200L / min for retrieval.

[0007] Specifically, the male and female connectors each have two circumferentially distributed Y-shaped channels forming a four-Y water eye with a diameter of 40mm. They are equipped with a BLY460 mud pump truck and use a large pumping capacity of 460L / min for retrieval.

[0008] Specifically, the outer layer of the male cone is 10mm thick, and the interior of the male cone is made of high-strength alloy steel; the outer and interior materials are formed by high-temperature die casting in one step.

[0009] Specifically, the maximum magnetic attraction force within 50mm of the surface of the male cone segment is 1046N.

[0010] Specifically, the male cone can achieve 360° rotation and ±5° deflection across the entire cross-section within the hole via a universal joint and a centering spring.

[0011] Specifically, the male connector is tapered in the rearward direction and matches the flared insertion groove of the female connector.

[0012] Specifically, in the positioning groove of the outer wall of the male connector, a positioning tooth is formed by a circumferential arc protrusion from the surface of the outer wall of the male connector. Each positioning tooth protrudes in an arc in the same direction in sequence, and the positioning groove is between adjacent positioning teeth. In the positioning groove of the female connector, the positioning teeth protruding on the inner wall of the insertion groove are recessed in a circumferential arc shape to the inner wall surface of the insertion groove to form a positioning groove, and each positioning tooth is recessed in an arc shape in the same direction to form a positioning groove. The positioning teeth of the male connector correspond to the positioning groove of the female connector, and the positioning groove of the male connector corresponds to the positioning teeth of the female connector, so as to realize the mating of the male connector and the female connector.

[0013] Specifically, the sensor display of the telescopic sensor is located at the orifice. The reading is positive when the straightening spring is compressed and negative when the straightening spring is stretched. The state of the straightening spring is determined by the positive or negative reading of the sensor display to determine whether the male cone has been attracted to the fish. When the retrieval tool is lowered into the designated position, the male cone is automatically moved to find the fish in the orifice and attracted to it by fine adjustment. The magnetic attraction causes the straightening spring to stretch, and the sensor display reading is negative. At this time, it is determined that the male cone has been successfully docked with the fish.

[0014] A method for using the aforementioned magnetic docking type retrieval tool for mining includes the following steps: Step 1: Assemble the magnetic docking fishing tool: Connect the male drill rod to the female threaded thread at the rear end of the magnetic docking fishing tool. Determine the length of the drill rod connection according to the position of the fish in the hole. After the connection is completed, feed the drill into the hole at a constant speed. If the male cone hits the hole wall during the lowering process, causing the drilling pressure to increase, move the drill rod back and forth to adjust its direction and continue lowering. Step 2: Reaching the predetermined position: After the male cone has been lowered to the fish landing position, lift the drill string slightly at a distance of 1m and record the pulling pressure at this time. Then continue lowering until it is 100mm behind the fish landing position. Reduce the lowering speed and continue to feed into the hole while monitoring the numbers on the sensor display at the hole opening. When the number becomes negative and stabilizes at a specific value, and the drill rod vibrates slightly, it is determined that the male cone has docked with the fish landing position. Mark the current position on the drill rod at the hole opening. If the sensor display reading does not change significantly and the driller does not feel significant vibration in the drill rod, continue to move the male cone slightly until the above situation occurs. Step 3: After the male cone and the fish are connected, continue to feed forward slowly. The sensor display reading will change from negative to 0 and from 0 to positive. This indicates that the straightening spring is gradually changing from a stretched state to a compressed state until it is compressed to its limit. At the same time, the drilling rig feed pressure also increases synchronously until it stabilizes. At this time, the male and female connectors are connected axially. Step 4: After the connector and the female connector are connected, stop feeding immediately when the sensor display reading is at its maximum or the drilling rig feed force is at its maximum. The drilling rig operation will then switch to rotation operation. Rotate slowly until the rotation pressure increases to a specific value, then stop rotating immediately. Step 5: Simultaneously perform slow feeding and slow rotation operations, and observe the feeding pressure and rotation pressure readings. If both the feeding pressure and rotation pressure slowly increase, it indicates that the male cone has penetrated into the fish and the silk-making is successful. Step 6: After successful wire forming, continue to maintain the above feed pressure and rotation pressure, or increase the feed pressure and rotation pressure according to the actual situation, until the drill rod marked in Step 2 enters the hole more than 500mm. At this time, stop rotation and feed. Step 7: Switch the drilling rig to forceful pulling. If the pressure reaches 10MPa or more during forceful pulling, the retrieval is successful. Continue to pull up the drill bit until all drill bits are pulled out of the hole. If the pressure during forceful pulling is significantly less than 10MPa or there is no significant change compared to the pulling pressure recorded in Step 2, it is determined that the fish has not been successfully retrieved. Exit the retrieval drill bit to check the cause, or replace the retrieval drill bit and repeat Step 1 to retrieve the fish again.

[0015] Compared with the prior art, the present invention has the following technical effects: (1) This invention innovatively designs a magnetic docking retrieval tool for mining. The device consists of two parts: a male cone and a connector. The core component is the connector. The magnetic docking principle is used to improve the accuracy of docking the retrieval tool with the fish that has fallen into the hole, thereby improving the retrieval efficiency.

[0016] (2) This invention proposes an operating process for a magnetic docking retrieval tool for mining. A key step is determining whether the retrieval tool has successfully docked with the fish that fell into the hole. This invention overcomes the limitations of conventional retrieval tools that rely solely on increased drilling pressure to determine successful docking. This reliance is subject to interference from factors such as the male cone penetrating the hole wall and increasing drilling pressure, or water clogging causing increased drilling pressure. Instead, it uses the elasticity of a built-in spring to determine whether the retrieval tool has successfully docked with the fish. This method is simple and intuitive, avoiding blind feeding due to misjudgment.

[0017] (3) The present invention uses the three-dimensional modeling software SolidWorks to establish a three-dimensional model of the magnetic docking salvage tool, which helps to realize mass production.

[0018] (4) Compared with existing technologies or processes, the present invention has the advantages of high docking accuracy and high retrieval efficiency. In traditional retrieval tools, the male cone is connected to the drill rod through a threaded connection and is rigid in the borehole. When docking with the fish buried in the hole, there is a situation where the end faces are touching, or the male cone is raised due to the bending of the borehole trajectory and sediment in the hole, causing the male cone to slide along the top of the borehole, which prevents the male cone from effectively entering the fish and thus cannot achieve wire formation. However, the magnetic docking retrieval tool adopts a universal head structure, that is, a universal head is installed on the inside of the female connector, which allows the male cone connected to it to achieve 360° rotation and ±5° deflection in the hole. Even if the male cone is raised by local sediment in the hole, the universal head can still achieve precise docking between the male cone and the fish in the hole, which greatly improves the docking success rate.

[0019] (5) This invention improves the efficiency of handling accidents in the borehole while reducing the cost of using (directional) drilling tools, which helps construction units reduce costs and increase efficiency.

[0020] (6) The core component of this invention, the connector and its internal parts, are machined parts or mature technologies. The male and female connectors are connected by tooth grooves. The structure is simple, the cost is low, and it is easy to mass-produce. It has broad market application prospects. Attached Figure Description

[0021] Figure 1 It refers to the connection method between the salvage tool and the drill pipe.

[0022] Figure 2 It is a magnetic docking type salvage tool structure.

[0023] Figure 3 This is a cross-sectional view (AA).

[0024] Figure 4 This is a cross-sectional view of BB.

[0025] Figure 5 It refers to the dimensions of the magnetic docking salvage tool.

[0026] Figure 6 It is an operation flowchart.

[0027] Figure 7 It is a three-dimensional structure (partially hidden) of a magnetic docking salvage tool.

[0028] Figure 8 It is a magnetic flux density diagram of the male cone end face.

[0029] Figure 9 It is a magnetic flux density diagram of the longitudinal section of the male cone.

[0030] Figure 10 It is the magnetic flux density curve within 50mm of the male cone end face.

[0031] Figure 11 This is a pressure and velocity contour plot when the water inlet diameter is 20mm and the pump flow rate is 200L / min.

[0032] Figure 12 This is a pressure and velocity contour plot when the water inlet diameter is 20mm and the pump flow rate is 390L / min.

[0033] Figure 13 This is a pressure and velocity contour plot when the water inlet diameter is 40mm and the pump flow rate is 460L / min.

[0034] The meanings of the labels in the diagram are as follows: 1. Male cone, 2. Female connector, 3. Universal joint, 4. Connecting rod, 5. Straightening spring, 6. Telescopic sensor, 7. Sealing sleeve, 8. Y-shaped channel, 11. Outer layer, 12. Inner layer, 13. Male connector. Detailed Implementation

[0035] 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.

[0036] Example 1: This embodiment provides a magnetic docking type salvage tool for mining, such as... Figures 1 to 10 As shown, it includes a male cone 1, a female connector 2, a universal joint 3, a connecting rod 4, a straightening spring 5, a telescopic sensor 6, and a sealing sleeve 7.

[0037] The male cone 1 has a conical section at the front, a middle section in the middle, and a male connector 13 at the rear. The outer layer 11 of the conical section is a neodymium iron boron magnet material layer, which is tightly bonded to the internal material 12 of the male cone 1 through welding or other special processes. The outer layer 11 has threads to allow for threading into the hole after successful docking. The thread type conforms to relevant standards, and the hardness is 50~60 HRC, while the hardness of the drill pipe steel is 42~46 HRC. The maximum magnetic energy product of the neodymium iron boron material itself can reach 400 KJ / m. 3 Because the male cone 1 is cone-shaped, the magnetic field lines are denser at the head of the male cone 1, resulting in a stronger magnetic field and magnetism. Therefore, theoretically, it is possible to achieve docking of the magnetic retrieval tool with the fish that has fallen into the hole and further rotational filament formation after docking. The male cone 1 has a water flow channel in the center, which branches into a Y-shaped channel 8 at the male connector 13. The outer wall of the male connector 13 has circumferentially distributed positioning tooth grooves.

[0038] The front of the female connector 2 is a insertion groove, and the rear can be connected to the drill pipe; the insertion groove can accommodate the axial insertion of the male connector 13; the inner sidewall of the insertion groove is evenly distributed with positioning groove teeth, which correspond one-to-one with the positioning grooves of the male connector 13. After the male connector 13 and the female connector 2 are inserted, the positioning grooves mesh with the positioning groove teeth to lock and transmit torque and axial force; the center of the female connector 2 is provided with a water flow channel and splits forward into a Y-shaped channel 8, which corresponds to the Y-shaped channel 8 of the male cone 1.

[0039] Universal joint 3 is located in the center of the bottom of the insertion slot. The front end of universal joint 3 is connected to the centering spring 5 via connecting rod 4. The front end of centering spring 5 is connected to the center of the rear end of male connector 13. An extension sensor 6 is installed inside centering spring 5. Tolerance connector is covered with sealing sleeve 7. The front end of sealing sleeve 7 is circumferentially connected to the outer wall of the front end of tolerance connector. The rear end of sealing sleeve 7 is circumferentially connected to the front end of female connector 2.

[0040] The male cone 1 and the female connector 2 are connected by a straightening spring 5 and a sealing sleeve 7, so that the front end of the male cone 1 always stays along the drilling axis during the process of being lowered into the hole, and has a certain degree of freedom so that it can be smoothly connected at the fish landing position; the Y-shaped water eye provides a flow channel for high-pressure circulating water, which can remove obstacles such as sediment and falling pieces in front of the male cone 1.

[0041] Both the male connector 13 and the female connector 2 are provided with a Y-shaped channel 8 to form a double Y-shaped water eye with a diameter of 20mm. It is equipped with a BLY390 mud pump truck and uses a pumping rate of 200L / min for retrieval.

[0042] The male connector 13 and the female connector 2 each have two circumferentially distributed Y-shaped channels 8 forming a four-Y water eye with a diameter of 40mm. They are equipped with a BLY460 mud pump truck and use a large pumping capacity of 460L / min for retrieval.

[0043] The outer layer 11 of the male cone 1 is 10mm thick, and the inner layer 12 of the male cone 1 is made of high-strength alloy steel. The outer layer 11 and the inner layer 12 are formed by high-temperature die casting in one step.

[0044] The maximum magnetic attraction force within 50mm of the surface of the cone section of male cone 1 is 1046N.

[0045] The male cone 1 can achieve 360° rotation and ±5° deflection across the entire cross section within the hole via the universal joint 3 and the centering spring 5.

[0046] The male connector 13 is tapered in the rearward direction and matches the flared insertion groove of the female connector 2.

[0047] In the positioning tooth groove on the outer wall of the male connector 13, a positioning tooth is formed by gradually arcing up from the surface of the outer wall of the male connector 13 in the circumferential direction. Each positioning tooth gradually arcs up in the same direction, and the positioning groove is between adjacent positioning teeth. In the positioning groove of the female connector 2, the positioning teeth protruding on the inner wall of the insertion groove gradually curve downwards in the circumferential direction to the inner wall surface of the insertion groove to form a positioning groove. Each protruding positioning tooth gradually curves downwards in the same direction to form a positioning groove. The positioning teeth of the male connector 13 correspond to the positioning groove of the female connector 2, and the positioning groove of the male connector 13 corresponds to the positioning teeth of the female connector 2, so as to realize the mating of the male connector 13 and the female connector 2.

[0048] The sensor display of the telescopic sensor 6 is located at the orifice. When the straightening spring 5 is compressed, the reading is positive, and when the straightening spring 5 is stretched, the reading is negative. The state of the straightening spring 5 is determined by the positive or negative reading of the sensor display to determine whether the male cone 1 has been attracted to the fish. When the retrieval tool is lowered into the designated position, the male cone 1 is automatically moved to find the fish in the orifice and attracted together by fine adjustment. The magnetic attraction causes the straightening spring 5 to stretch, and the sensor display reading is negative. At this time, it is determined that the male cone 1 has been docked with the fish.

[0049] In this embodiment, the male connector and the male taper are integrated, with positioning grooves milled out during milling. The male taper is 600mm long, with an inner layer made of high-strength alloy steel and an outer layer made of neodymium iron boron magnet material, which has strong magnetism and facilitates the placement of the drill bit into the mating hole. The outer layer is 10mm thick. The inner and outer layers are formed in one piece using a high-temperature die-casting process, and the outer layer has fine-tooth threads for easy wire forming.

[0050] The magnetic field of the male cone was simulated using COMSOL simulation software. The results show that the maximum magnetic flux density modulus within a 50 mm radius of the male cone tip reaches 1.41 T. Figure 8-10 As shown, according to Maxwell's magnetic attraction formula: ① ② In the formula: —The attractive force of a magnet on a magnetic material, measured in N; —Magnetic flux density, unit: T; —The area of ​​the magnetic poles of a magnet, in meters. 2 ; —Vacuum permeability, typically taken as 1; —Magnetic flux density modulus, unit: T.

[0051] According to equations ① and ②, we can obtain... ③ Therefore, based on the simulation results and combined with Equation ③, the maximum magnetic attraction force within a 50mm radius of the male cone tip surface can be calculated to be approximately 1046N. This theoretically ensures that the male cone tip possesses sufficient magnetic force.

[0052] The male connector has four positioning teeth on its outer side and four on its inner side. In actual use, the shape, size, and number of these positioning teeth and grooves can be adjusted according to the torque transmission effect. In this embodiment, the male connector has an axially protruding arc-shaped positioning tooth groove on its outer side. Each positioning tooth is 50mm long, with an outer diameter of 60-70mm, an inner diameter of 50-60mm, and a thickness of 0-5mm. Four positioning teeth are evenly arranged circumferentially along the male connector, with adjacent positioning teeth connected end-to-end, and a positioning groove between adjacent teeth. The female connector has arc-shaped positioning grooves, each groove being 50mm long, with an outer diameter of 60-70mm, an inner diameter of 50-60mm, and a thickness of 0-5mm. Four positioning grooves are evenly arranged circumferentially along the female connector, with adjacent positioning grooves connected end-to-end, and a positioning tooth between adjacent grooves. During use, when the feed force compresses the centering spring, the male and female connectors mesh. Rotation causes the positioning teeth to enter the positioning grooves, locking the male and female connectors and enabling the transmission of torque and axial force.

[0053] The female connector features a 16mm diameter spherical universal joint at its inner center, allowing the male drill bit to rotate 360° and tilt ±5° within the borehole. A 20mm diameter, 90mm long centering spring connects to the front of the universal joint, with the other side of the spring connected to the male connector. The universal joint and centering spring are connected via a connecting rod, with the front of the spring connected to the rear of the male connector. This allows the feed force acting on the drill rod to be elastically transmitted to the male drill bit axially via the centering spring, and radially, the male drill bit can tilt ±5° in any direction within the borehole cross-section via the universal joint. This enables the attraction of ferromagnetic objects across the entire borehole cross-section, ensuring flexibility when the male drill bit docks with a fish in the borehole. A 50mm long wireless telescopic sensor with micron-level accuracy is located inside the centering spring. The sensor display is located at the borehole opening; the sensor is set before use, with a positive reading when the spring is compressed and a negative reading when the spring is extended. The state of the centering spring can be visually determined by the reading on the display, which in turn indicates whether the male cone has been attracted to the fish. After the retrieval tool is lowered into the designated position, a small range of movement causes the male cone to automatically locate the fish in the hole and attract it. Due to the magnetic attraction, the centering spring is stretched, and the display reading becomes negative. At this point, it can be determined that the male cone has successfully docked with the fish, and the next step can be performed.

[0054] Both the male and female connectors have internal water inlets with diameters ranging from 10mm to 40mm. High-pressure water enters the female connector through the drill pipe and is diverted by the Y-shaped water inlets. The water flows along both sides of the female connector into the area between the male and female connectors, then converges through the Y-shaped water inlets on both sides of the male connector before being ejected through the male conical water inlet, effectively flushing away rock debris and cooling the surface. The double Y-shaped water inlet design ensures a high-pressure water flow channel within the retrieval tool while preventing direct impact of high-pressure water on the centering spring and universal joint, thus guaranteeing the reliability of the components. The double Y-shaped water inlets can meet the requirements of typical borehole retrieval operations. Specifically, if the borehole has already been cleaned of sediment and debris using conventional drilling tools before the magnetic docking retrieval tool is lowered, then a high pump flow rate is not necessary after lowering the magnetic docking retrieval tool, as the flow cross-section of the double Y-shaped water inlets can meet the required flow rate. However, considering that replacing conventional drilling tools and re-drilling the hole takes a lot of time, especially in deep directional boreholes, replacing drilling tools and re-drilling the hole often takes a whole shift, it is necessary to adjust the water jet structure to single or multiple jets according to the pump flow rate. The water jet trajectory can also be adjusted to other curved shapes to adapt to the needs of different drilling tool gradations and pump truck displacements.

[0055] The flow field of double-Y and quad-Y water jets was simulated using ANSYS software, and the results are as follows: Figure 11-13 As shown, Figure 11 In the diagram, we have: a) pressure cloud map with Φ=20mm and v=10m / s (i.e., pump flow rate 200L / min); b) joint surface pressure cloud map with Φ=20mm and v=10m / s (i.e., pump flow rate 200L / min); and c) velocity cloud map with Φ=20mm and v=10m / s (i.e., pump flow rate 200L / min). Figure 12 In the diagram, we have: a) pressure cloud map with Φ=20mm and v=20m / s (i.e., pump flow rate 390L / min); b) joint surface pressure cloud map with Φ=20mm and v=20m / s (i.e., pump flow rate 200L / min); and c) velocity cloud map with Φ=20mm and v=20m / s (i.e., pump flow rate 390L / min). Figure 13The diagrams show pressure contours for: a) Φ=40mm, v=6m / s (i.e., pump flow rate 460L / min); b) interface pressure contours for: Φ=40mm, v=6m / s (i.e., pump flow rate 400L / min); and c) velocity contours for: Φ=40mm, v=6m / s (i.e., pump flow rate 460L / min). When the water inlet diameter is 20mm, paired with a BLY390 mud pump truck, and using a medium pump flow rate (200L / min) for salvage operations, the maximum water pressure in the water inlet is 82Pa, and the minimum flow velocity is 2.26m / s. At this point, the pump flow rate and water inlet are well matched, and pressure buildup will not occur. When the water inlet diameter is 20mm, paired with a BLY390 mud pump truck, and using a large pump flow rate (390L / min) for salvage operations, the maximum water pressure in the water inlet is 300Pa, and the minimum flow velocity is 6.6m / s. At this point, slight pump buildup will occur, which is detrimental to equipment operation. When the water inlet diameter is adjusted to 40mm and the water inlet structure is adjusted to a four-Y type, due to the increased flow cross-section, a BLY460 type mud pump truck should be used with a large pump flow rate (460L / min) for retrieval. The maximum water pressure in the water inlet is 32Pa, and the minimum flow velocity is 2.8m / s. At this point, the pump flow rate matches the water inlet structure well, and pump blockage will not occur. Comprehensive simulation results show that a double-Y type water inlet is best used with a BLY390 type mud pump truck with a medium pump flow rate for retrieval, while a four-Y type water inlet requires a BLY460 type mud pump truck with a large pump flow rate for retrieval.

[0056] The male and female connectors are connected by a rubber sleeve on the outside, which seals the internal parts and effectively prevents coal slag from entering the connector. The rubber sleeve connection is flexible and does not restrict the male cone's freedom of movement, thus not affecting its guiding function. The sealing rubber sleeve is 130mm long, with an outer diameter of 89mm and an inner diameter of 79mm.

[0057] Example 2: This embodiment provides a method for using a magnetic docking retrieval tool for mining. The method is implemented using the magnetic docking retrieval tool and includes the following steps: Step 1: Assemble the magnetic docking fishing tool: Connect the male drill rod to the female threaded thread at the rear end of the magnetic docking fishing tool. Determine the length of the drill rod connection according to the position of the fish in the hole. After the connection is completed, feed the drill into the hole at a constant speed. If the male cone hits the hole wall during the lowering process, causing the drilling pressure to increase, the drill rod needs to be moved back and forth to adjust its direction and continue lowering. Step 2: Reaching the predetermined position: After the male cone has been lowered to the fish landing position, lift the drill string slightly about 1m away and record the pulling pressure at this time. Then continue lowering it until it is about 100mm away from the fish landing position. Reduce the lowering speed and continue to feed into the hole while closely monitoring the numbers on the sensor display at the hole opening. When the number becomes negative and stabilizes at a specific value, and the driller feels a slight vibration in the drill rod (the degree of vibration varies depending on the depth of the fish landing position), it can be determined that the male cone has docked with the fish landing position. Mark the current position on the drill rod at the hole opening and then proceed to the next step. If the sensor display reading does not change significantly and the driller does not feel a significant vibration in the drill rod, continue to move the male cone slightly until the above situation occurs. Step 3: After the male cone and the fish are connected, continue to feed forward slowly. The sensor display reading will change from negative to 0 and then from 0 to positive. This indicates that the centering spring is gradually changing from a stretched state to a compressed state until it is compressed to its limit. At the same time, the drilling rig feed pressure will also increase synchronously until it stabilizes at a certain value. At this time, the male and female connectors are axially connected, but the positioning teeth and positioning grooves are not necessarily fully engaged. Therefore, the next step needs to be performed. Step 4: After the connector and the female connector are connected, that is, when the sensor display reading is at its maximum or the drilling rig feed force is at its maximum, immediately stop the feed. The drilling rig operation is changed to rotation operation. Similarly, rotate slowly until the rotation pressure increases to a certain specific value, and then stop the rotation immediately. Step 5: Simultaneously perform slow feeding and slow rotation operations, and observe the feeding pressure and rotation pressure readings. At this time, both the feeding pressure and rotation pressure will slowly increase, indicating that the male cone has penetrated into the fish and the silk-making is successful. Step 6: After successful wire forming, continue to maintain the above feed pressure and rotation pressure, or increase the feed pressure and rotation pressure appropriately according to the actual situation, until the drill rod marked in Step 2 enters the hole more than 500mm. At this time, stop rotation and feed. Step 7: Switch the drilling rig to forceful pulling and observe whether the pulling pressure reaches 10MPa (this value is an empirical value; the specific value needs to be determined based on the number of remaining drill bits in the hole, the location of the fish, and whether the fish is buried or crushed). If the pressure reaches more than 10MPa during forceful pulling, it indicates that the retrieval is successful, and the drill bits can be raised until all drill bits are pulled out of the hole. If the pressure during forceful pulling is significantly less than 10MPa or there is no significant change compared to the pulling pressure recorded in Step 2, it can be determined that the fish has not been successfully retrieved. The retrieval drill bit needs to be removed to check the cause, or the retrieval drill bit needs to be replaced and Step 1 needs to be repeated for retrieval.

[0058] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0059] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0060] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A magnetic docking type fishing tool for mining, characterized by, It comprises a male taper (1), a female adapter (2), a universal head (3), a connecting rod (4), a centralizing spring (5), an expansion sensor (6), a sealing rubber sleeve (7); The front section of the male taper (1) is a taper section, the middle section is a middle section, and the rear section is a male adapter (13). The outer layer (11) of the taper section is a layer of neodymium iron boron magnet material, which is tightly attached to the inner part (12) of the male taper (1) and has threads on the outer layer (11) to generate a wire inside the drill tool after successful connection. The male taper (1) is provided with a water flow channel in the center and is divided into a Y-shaped channel (8) at the rear of the male adapter (13). The outer wall of the male adapter (13) is provided with circumferentially distributed positioning teeth. The front part of the female adapter (2) is an adapter slot, and the rear part can be connected with a drill rod. The adapter slot can correspondingly accommodate the axial insertion of the male adapter (13). The circumferentially distributed positioning teeth on the inner wall of the adapter slot correspond one-to-one with the positioning teeth of the male adapter (13). After the male adapter (13) is inserted into the female adapter (2), the positioning teeth and the positioning teeth are engaged to achieve locking to transmit torque and axial force. The female adapter (2) is provided with a water flow channel in the center and is divided into a Y-shaped channel (8) forward and corresponds to the Y-shaped channel (8) of the male taper (1). The universal head (3) is arranged in the center of the bottom of the adapter slot. The front end of the universal head (3) is connected to the connecting rod (4), and the front end of the connecting rod (4) is connected to the rear end center of the male adapter (13). The universal head (3) is provided with an expansion sensor (6) in the center. The outer sleeve of the universal joint is provided with a sealing rubber sleeve (7). The front end of the sealing rubber sleeve (7) is circumferentially connected to the outer wall of the front end of the universal joint, and the rear end of the sealing rubber sleeve (7) is circumferentially connected to the front end of the female adapter (2).

2. The magnetic docking type fishing tool for mines according to claim 1, characterized in that, The male adapter (13) and the female adapter (2) are each provided with a Y-shaped channel (8) to form a double-Y-shaped water eye with a diameter of 20mm. It is matched with a BLY390 type mud pump truck and uses a medium pump capacity of 200L / min for fishing.

3. The magnetic docking type fishing tool for mines according to claim 1, characterized in that, The male adapter (13) and the female adapter (2) are each provided with two circumferentially distributed Y-shaped channels (8) to form a four-Y-shaped water eye with a diameter of 40mm. It is matched with a BLY460 type mud pump truck and uses a large pump capacity of 460L / min for fishing.

4. The magnetic docking overshot tool of claim 1, wherein, The thickness of the outer layer (11) of the male taper (1) is 10mm, and the inner part (12) of the male taper (1) is made of high-strength alloy steel material. The outer layer (11) and the inner part (12) are made of high-temperature pressure casting one-step forming process.

5. The magnetic docking overshot tool of claim 4, wherein, The maximum magnetic attraction force of the taper section surface of the male taper (1) within a range of 50mm is 1046N.

6. The magnetic docking overshot tool of claim 1, wherein, The male taper (1) can rotate 360° and ±5° in the hole by the universal head (3) and the centralizing spring (5).

7. The magnetic docking overshot tool of claim 1, wherein, The male adapter (13) is a reduced diameter in the rear direction and is matched with the horn-shaped adapter slot of the female adapter (2).

8. The magnetic docking overshot tool of claim 1, wherein, The positioning teeth groove on the outer wall of the male adapter (13) is formed by a positioning tooth protruding along the circumferential arc of the outer wall surface of the male adapter (13). Each positioning tooth protrudes along the same direction in sequence, and the adjacent positioning teeth form a positioning groove. The positioning teeth of the female connector (2) are arranged in the positioning groove teeth, and the positioning teeth protruding from the inner wall of the connector groove are arc-shaped concave to the inner wall surface of the connector groove to form a positioning groove, and each positioning tooth is arc-shaped concave to the positioning groove in the same direction; The positioning teeth of the male connector (13) correspond to the positioning grooves of the female connector (2), and the positioning grooves of the male connector (13) correspond to the positioning teeth of the female connector (2), so that the male connector (13) is matched with the female connector (2).

9. The magnetic docking overshot tool of claim 1, wherein, The sensor display instrument of the telescopic sensor (6) is located at the orifice, and the reading is positive when the centralizing spring (5) is compressed and negative when the centralizing spring (5) is stretched; the state of the centralizing spring (5) is judged according to the positive and negative readings of the sensor display instrument to judge whether the male taper (1) is sucked with the fish; after the fishing tool is lowered to the specified position, the male taper (1) automatically finds the fish in the hole and is sucked together through fine adjustment, the centralizing spring (5) is stretched due to magnetic attraction, the sensor display instrument reading is negative, and at this time it is determined that the male taper (1) has completed the butt joint with the fish.

10. A method of using the mining magnetic docking type fishing tool according to any one of claims 1 to 9, characterized in that, The method comprises the following steps: Step 1: Assemble the magnetic attraction butt joint type fishing tool: connect the drill rod male buckle to the female buckle at the rear end of the magnetic attraction butt joint type fishing tool, determine the length of the drill rod to be connected according to the position of the fish in the hole, and after the connection is completed, uniformly lower into the hole through the drilling machine, if the drill pressure increases due to the fact that the male taper is on the hole wall during the lowering process, adjust the direction of the drill rod to continue to lower into the hole; Step 2: Reach the predetermined position: after the male taper is lowered to 1m away from the fish position, record the pulling pressure by slightly raising the drill once, then continue to lower until 100mm away from the fish position, continue to feed into the hole at a reduced speed and pay attention to the number on the orifice sensor display instrument, when the number becomes negative and stabilizes at a specific value, and the drill rod appears slight vibration, it is judged that the male taper has been butt jointed with the fish, and the current position is marked on the drill rod at the orifice; if the sensor display instrument reading does not change obviously and the driller does not feel obvious vibration of the drill rod, continue to slightly move the male taper until the above-mentioned situation occurs; Step 3: After the male taper is butt jointed with the fish, continue to slowly feed forward, the sensor display instrument reading will change from negative to 0, and then from 0 to positive, indicating that the centralizing spring gradually changes from the stretched state to the compressed state, until it is compressed to the limit state, at the same time, the drilling machine feeding pressure also increases synchronously until it stabilizes at a certain value, at this time, the male connector is connected with the female connector in the axial direction; Step 4: After the male connector is connected with the female connector, stop feeding immediately when the sensor display instrument reading is maximum or the drilling machine feeding force is maximum, change the drilling machine operation to rotation operation, and also slowly rotate until the rotation pressure increases to a specific value and then stop rotating immediately; Step 5: Slowly feed and slowly rotate at the same time, observe the feeding pressure and rotation pressure readings, and if both the feeding pressure and the rotation pressure slowly increase, it indicates that the male taper has been eaten into the fish and the fishing is successful. Step 6: After the successful wireline, continue to maintain the above feeding pressure and rotary pressure or increase the feeding pressure and rotary pressure according to the actual situation until the marked drill pipe in step 2 enters the hole more than 500 mm, at which time the rotation and feeding are stopped; Step 7: The drilling machine operation is changed to strong pulling, if the pressure can reach more than 10 MPa when the strong pulling, it means that the fishing is successful, continue to pull up the drilling tools until all the drilling tools are pulled out of the hole; If the pressure is obviously less than 10 MPa or there is no obvious change compared with the pulling pressure recorded in step 2, it is judged that the fish is not successfully fished, the fishing drill pipe is withdrawn for inspection, or the fishing drill pipe is replaced and step 1 is repeated again to fish.

Images