A coring device

Abstract

The application discloses a coring device and belongs to the technical field of drilling engineering construction, which comprises a connecting head, a buffer rubber fixedly installed at the other end of the connecting head, a connecting seat frictionally and drivably connected with the buffer rubber, an upper pre-tightening joint threadedly connected at the end of the connecting seat away from the buffer rubber, an outer pipe threadedly connected with the upper pre-tightening joint, a lower pre-tightening joint threadedly connected at the other end of the outer pipe, a pre-tightening support pipe arranged in the outer pipe, the pre-tightening support pipe being located between the upper pre-tightening joint and the lower pre-tightening joint, an outer drill bit threadedly connected at the other end of the lower pre-tightening joint, a boss protruding into the pre-tightening support pipe arranged at the end of the connecting seat, a rotating shaft rotatably installed on the boss, and an inner pipe fixedly installed on the rotating shaft and used for extracting a core sample. The application solves the technical problem that the drilling rod and the coring outer pipe are bent and deformed, thus causing the coring position to be greatly deviated, and is widely applied to drilling engineering construction.

Description

Technical Field

[0001] This invention belongs to the field of drilling engineering construction technology, and particularly relates to a core sampling device. Background Technology

[0002] In geological exploration drilling operations, core sampling is a commonly used method to obtain accurate geological data. It can accurately understand the engineering geological and hydrogeological issues related to hydraulic structures (dams, tunnels, power plants, etc.). There are many types of commonly used core sampling devices, among which the single-action double-tube structure is widely used in complex strata. However, some problems exist during its use, especially in some deep and complex core sampling locations. Due to the applied drilling pressure, the drill rod is prone to bending and deformation. Since the drill rod and the core sampler are rigidly connected, this can cause the core sampling device to deviate. In addition, because the outer tube of the core sampling device is generally thin and has poor rigidity, it will also undergo elastic deformation, leading to increasingly larger deviations in the core sampling position. Therefore, how to ensure the accuracy of the core sampling position without affecting subsequent drilling is a problem worth exploring and a technical challenge that has troubled those skilled in the art.

[0003] Therefore, in the field of drilling engineering construction technology, there is still a need for research and improvement of coring devices. This is a current research hotspot and focus in the field of drilling engineering construction technology, and it is also the starting point for the completion of this invention. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a coring device to solve the technical problem of large deviation in coring position caused by bending deformation of drill rod and coring outer tube.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is: a coring device, comprising a connector threadedly connected to a drill rod, a buffer rubber fixedly installed at the other end of the connector, a connecting seat frictionally connected to the buffer rubber, an upper pre-tightening joint threadedly connected to the end of the connecting seat away from the buffer rubber, an upper pre-tightening joint threadedly connected to an outer tube, a lower pre-tightening joint threadedly connected to the other end of the outer tube, a pre-tightening support tube provided inside the outer tube, the pre-tightening support tube being located between the upper and lower pre-tightening joints, and an outer drill bit threadedly connected to the other end of the lower pre-tightening joint. The end of the connector has a boss that extends into the pre-tightening support tube. A rotating shaft is rotatably mounted on the boss, and an inner tube for extracting the core sample is fixedly mounted on the rotating shaft. The end of the inner tube is provided with a clamp. The inner cavity of the inner tube is connected to the center hole of the outer drill bit. An annular cavity is provided between the pre-tightening support tube and the inner tube. The annular cavity is connected to the flushing hole on the outer drill bit. A central channel is provided through the connector, the buffer rubber, and the connector. The connector is provided with a connecting channel that connects the central channel and the annular cavity. A one-way valve is provided between the central channel and the connecting channel.

[0006] As an improvement, the outer surface of the connecting seat is provided with several sets of protruding supports for pressing against the inner wall of the drill hole.

[0007] As a further improvement, the extendable support includes a radial groove formed on the connecting seat, a telescopic block is radially slidably installed in the radial groove, a pressure plate is installed on the connecting seat by a clamping screw to restrict the telescopic block from sliding out of the radial groove, an expansion capsule is provided in the radial groove, the expansion capsule is connected to the central channel, and a force-applying spring is provided in the radial groove to press the telescopic block against the expansion capsule.

[0008] As another improvement, the connector is provided with a cavity, and the connector head is provided with a spline groove at one end of the cavity. The buffer rubber includes a rubber sleeve covering the outer periphery of the spline groove and an end face rubber fixed to the end face of the connector head by a fixing screw.

[0009] As a further improvement, the one-way valve includes a screw plug disposed on the connecting seat at the end of the central channel, a steel ball is provided in the central channel to isolate the central channel from the connecting channel, and a compression spring is provided between the steel ball and the screw plug.

[0010] As a further improvement, an upper preload blade with a protruding cutting edge is installed on the outer periphery of the upper preload joint, and a lower preload blade with a protruding cutting edge is installed on the outer periphery of the lower preload joint.

[0011] As a further improvement, the rotating shaft is rotatably mounted on the bearing housing, the bearing housing is threadedly connected to the boss, one end of the rotating shaft away from the inner tube extends out of the bearing housing and a buffer nut is installed at the end, and a buffer spring is provided between the buffer nut and the bearing housing.

[0012] As a further improvement, the inner tube is threaded onto the end connector, the end connector is threaded onto the rotating shaft, and an adjusting nut is threaded onto the rotating shaft, the adjusting nut abutting against the end connector.

[0013] As a further improvement, a semi-closed pipe upper connector is fixedly connected to the end connector, the inner pipe is threadedly connected to the semi-closed pipe upper connector, the other end of the inner pipe is threadedly connected to a semi-closed pipe lower connector, and the semi-closed pipe lower connector is threadedly connected to the clamp.

[0014] As a further improvement, a straightening ring is provided between the lower pre-tightening joint and the lower half-closed pipe joint. The straightening ring is located in the annular cavity and has several axially arranged through holes.

[0015] After adopting the above technical solution, the beneficial effects of the present invention are:

[0016] (1) In the embodiment of the present invention, the connector is connected to the connecting seat through friction transmission of buffer rubber. The buffer rubber acts as an elastic coupling, which can effectively absorb the axial bending moment of the drill rod and does not affect the transmission of radial torque. Furthermore, the buffer rubber absorbs the axial bending moment of the drill rod, avoiding the axial bending moment of the drill rod from affecting the deformation of the outer tube and ensuring the accuracy of the core sampling position.

[0017] (2) In this embodiment of the invention, an upper pre-tightening joint and a lower pre-tightening joint are provided, and a pre-tightening support tube is provided inside the outer tube. By rotating the upper pre-tightening joint and the lower pre-tightening joint, axial pre-tightening tension is applied to the outer tube. At this time, the outer tube is in a tensioned state and the pre-tightening support tube is in a compressed state. Due to the radial constraint effect of the outer tube on the pre-tightening support tube, the pre-tightening support tube does not produce outward radial deformation and plays a supporting role on the outer tube. When the tensile force is greater than the axial load of the drill pipe, the axial load of the drill pipe is balanced with the pre-tightening force of the outer tube, thus reducing the bending deformation of the outer tube.

[0018] (3) In the embodiment of the present invention, an expansion capsule is provided in the radial groove, and a force spring is provided in the radial groove to press the telescopic block against the expansion capsule. During the drilling process, the flushing fluid enters the expansion capsule, overcomes the force of the force spring, and the telescopic block extends out and presses against the inner wall of the borehole, thus ensuring the accuracy of the drilling direction.

[0019] (4) Because a buffer spring is provided between the buffer nut and the bearing seat, the vibration during the core extraction process is reduced, the core drop phenomenon is prevented, and the core collection rate is improved. Attached Figure Description

[0020] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0021] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0022] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0023] The components are as follows: 1. Drill pipe; 2. Connector; 3. Bolt; 4. Gland; 5. Buffer rubber; 6. Connecting seat; 7. Telescopic block; 8. Expansion capsule; 9. Tension spring; 10. Upper gauge-maintaining blade; 11. Upper pre-tightening joint; 12. Outer tube; 13. Pre-tightening support tube; 14. Lower pre-tightening joint; 15. Lower gauge-maintaining blade; 16. Centralizing ring; 17. Outer drill bit; 18. Clamp; 19. Inner tube; 20. Rotary shaft; 21. End joint; 22. Adjusting nut; 23. 101 Rolling bearing; 24 Thrust bearing; 25 Bearing housing; 26 Buffer spring; 27 Buffer nut; 28 Plug; 29 Compression spring; 30 Steel ball; 31 Pressure plate; 32 Clamping screw; 33 Spline sleeve; 34 Clamping nut; 35 Core; 101 Extending support; 102 Check valve; 501 Rubber sleeve; 502 End face rubber; 503 Fixing screw; 191 Upper connector of semi-closed pipe; 192 Lower connector of semi-closed pipe. Detailed Implementation

[0024] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The terms used in this specification, such as "front," "back," "left," "right," "inner," "outer," and "middle," are merely for clarity of description and are not intended to limit the scope of the invention. Any changes or adjustments to their relative relationships, without substantially altering the technical content, shall also be considered within the scope of the invention.

[0026] like Figure 1As shown, a coring device includes a connector 2 threadedly connected to a drill rod 1. A buffer rubber 5 is fixedly installed at the other end of the connector 2. The buffer rubber 5 is frictionally connected to a connecting seat 6. The buffer rubber 5 transmits the power of the drill rod 1 to the connecting seat 6 through friction, causing the connecting seat 6 to rotate. The buffer rubber 5 acts as an elastic coupling, effectively absorbing the axial bending moment of the drill rod 1 without affecting the transmission of radial torque. An upper pre-tightening connector 11 is threaded to the end of the connecting seat 6 away from the buffer rubber 5. The upper pre-tightening connector 11 is threaded to an outer tube 12. The other end of the outer tube 12 is threaded to a lower pre-tightening connector 14. The outer tube 12 is equipped with a pre-tightening support tube 13, which is located between the upper pre-tightening joint 11 and the lower pre-tightening joint 14. By rotating the upper pre-tightening joint 11 and the lower pre-tightening joint 14, axial pre-tightening tension is applied to the outer tube 12. At this time, the outer tube 12 is in a tensioned state, and the pre-tightening support tube 13 is in a compressed state. Due to the radial constraint of the outer tube 12 on the pre-tightening support tube 13, the pre-tightening support tube 13 does not produce outward radial deformation and plays a supporting role for the outer tube 12. When the tensile force is greater than the axial load of the drill pipe 1, the axial load of the drill pipe 1 is balanced with the pre-tension force of the outer tube 12, thus reducing the bending deformation of the outer tube 12. The other end of connector 14 is threaded to the outer drill bit 17. The end of connector 6 has a boss that extends into the pre-tightening support tube 13. A rotating shaft 20 is rotatably mounted on the boss. An inner tube 19 for extracting the core sample 35 is fixedly mounted on the rotating shaft 20. A clamp 18 is provided at the end of the inner tube 19. During drilling, the outer tube 12 rotates while drilling, and the inner tube 19 drills along with it without rotating, ensuring the cutting and extraction of the core sample 35. The inner cavity of the inner tube 19 is connected to the center hole of the outer drill bit 17. An annular cavity is provided between the pre-tightening support tube and the inner tube 19. The annular cavity is connected to the flushing hole on the outer drill bit 17. The connector 2 passes through. The buffer rubber 5 and the connecting seat 6 are provided with a central channel. The connecting seat 6 is provided with a connecting channel that connects the central channel and the annular cavity. A one-way valve 102 is provided between the central channel and the connecting channel. Specifically, the one-way valve 102 includes a screw plug 28 located at the end of the central channel on the connecting seat 6. A steel ball 30 is provided in the central channel to isolate the central channel and the connecting channel. A compression spring 29 is provided between the steel ball 30 and the screw plug 28. When the drilling fluid pressure reaches a certain pressure, the compression spring 29 is compressed, which pushes open the steel ball 30 of the one-way valve 102, and the drilling fluid enters the annular cavity between the inner tube 19 and the outer tube 12 and reaches the bottom of the drill bit.

[0027] The outer surface of the connecting seat 6 is provided with several sets of protruding supports 101 for pressing against the inner wall of the drill hole. The protruding supports 101 include radial grooves formed on the connecting seat 6. The radial grooves are open grooves that extend radially on the connecting seat 6. Telescopic blocks 7 are radially slidably installed in the radial grooves. A pressure plate 31 is installed on the connecting seat 6 by clamping screws 32 to restrict the telescopic blocks 7 from sliding out of the radial grooves. Typically, the telescopic blocks 7 have a T-shaped structure. The large end slides in the radial groove and is constrained by the pressure plate 31, while the small end can extend out of the outer surface of the connecting seat 6 to press against the drill hole. The inner wall serves as a guide and positioning element. An expansion capsule 8 is installed in the radial groove, which is connected to the central channel. A force spring, typically a tension spring 9, is installed in the radial groove to press the telescopic block 7 against the expansion capsule 8. One end of the tension spring 9 is connected to the telescopic block 7, and the other end is connected to the bottom of the radial groove. When stationary, the telescopic block 7 is retracted into the connecting seat 6 under the tension of the tension spring 9. During operation, the flushing fluid enters the expansion capsule 8, overcoming the force of the force spring. The expansion capsule 8 pushes the telescopic block 7 out and presses it tightly against the inner wall of the borehole, ensuring the accuracy of the drilling direction.

[0028] The connecting seat 6 has a cavity, one end of which is open. A pressure cap 4 is installed on the open end by bolts 3. One end of the connecting head 2 is located in the cavity, and the other end extends out of the pressure cap 4 to connect to the drill rod. The connecting head 2 has a spline groove at one end located in the cavity. The buffer rubber 5 includes a rubber sleeve 501 covering the outer periphery of the spline groove and an end face rubber 502 fixed to the end face of the connecting head 2 by fixing screws 503. The rubber sleeve 501 covers the spline groove and is firmly connected, which can effectively transmit torque. The outer periphery of the rubber sleeve 501 abuts against the connecting seat 6 to realize friction transmission. The end face rubber 502 is fixed to the end of the connecting head 2 and abuts against the cavity, which can effectively absorb the axial bending moment from the drill rod 1.

[0029] An upper gauge-maintaining blade 10 with a protruding cutting edge is installed on the outer periphery of the upper pre-tightening joint 11, and a lower gauge-maintaining blade 15 with a protruding cutting edge is installed on the outer periphery of the lower pre-tightening joint 14. The upper gauge-maintaining blade 10 and the lower gauge-maintaining blade 15 can press against the inner wall of the borehole, ensuring the accuracy of the drilling direction of the outer tube 12.

[0030] The rotating shaft 20 is rotatably mounted on the bearing housing 25. Specifically, a spline sleeve 33 is fitted on the rotating shaft 20, and two sets of bearings are fitted on the spline sleeve 33. Each set of bearings includes a rolling bearing 23 and a thrust bearing 24. The two sets of bearings are located at both ends of the bearing housing 25, ensuring bearing load and radial load. The bearing housing 25 is threadedly connected to the boss. The end of the rotating shaft 20 away from the inner tube 19 extends out of the bearing housing 25 and is fitted with a buffer nut 27. A buffer spring 26 is provided between the buffer nut 27 and the bearing housing 25. A clamping nut 34 is threadedly installed on the spline sleeve 33, pressing against the rolling bearing 23, so that the rolling bearing 23 and the thrust bearing 24 are firmly installed on the bearing housing 25, ensuring that the outer tube 12 rotates while the inner tube 19 remains stationary during core extraction. The buffer spring 26 is clamped between the buffer nut 27 and the clamping nut 34 to reduce vibration during core extraction, prevent core loss, and improve the core collection rate.

[0031] The inner tube 19 is threaded onto the end connector 21, which is threaded onto the rotating shaft 20. An adjusting nut 22 is threaded onto the rotating shaft 20, abutting against the end connector 21. A semi-closed tube upper connector 191 is fixedly connected to the end connector 21. The inner tube 19 is threaded onto the semi-closed tube upper connector 191, and the other end of the inner tube 19 is threaded onto a semi-closed tube lower connector 192. The inner tube 19 is a semi-closed tube to ensure minimal disturbance during core extraction. The lower connector 192 is threadedly connected to the clamp 18. The adjusting nut 22 is used to adjust the distance between the clamp 18 on the inner tube 19 and the outer drill bit 17. A straightening ring 16 is provided between the lower pre-tightening connector 14 and the semi-closed pipe lower connector 192. The straightening ring 16 is slidably connected to the inner tube 19 and the semi-closed pipe lower connector 192. The outer circumference of the straightening ring 16 is clamped on the inner wall of the lower pre-tightening connector 14. The straightening ring 16 is located in the annular cavity. The straightening ring 16 is provided with several axially arranged through holes to ensure the smooth flow of flushing fluid.

[0032] The operation process of this invention embodiment is as follows:

[0033] 1. Check whether the connections of each component are normal. Replace the appropriate external drill bit 17 and clamp 18 according to the geological conditions. Adjust the adjusting nut 22 so that the external drill bit 17 and clamp 18 are at the appropriate distance. Assemble each component from the inside to the outside.

[0034] 2. Connect drill rod 1 and send the outer drill bit 17 to the core sampling position at the bottom of the borehole.

[0035] 3. Turn on the flushing fluid. The flushing fluid reaches the one-way valve 102 through the middle channel and the central channel of the drill pipe 1. Due to the opening pressure of the one-way valve 102, the flushing fluid first enters the expansion capsule 8, causing the expansion capsule 8 to expand and push the telescopic block 7 out and tighten it against the hole wall. As the flushing fluid pressure increases, the one-way valve 102 is opened, and the flushing fluid enters the annular cavity between the inner tube 19 and the outer tube 12, and then flows out from the drill bit hole.

[0036] 4. Rotate drill rod 1 and apply axial pressure to drill rod 1. The torque and pressure are transmitted to connecting seat 6 through connecting head 2 and buffer rubber 5. Connecting seat 6 transmits power to outer drill bit 17 through outer tube 12. Under the rotation and propulsion force of outer drill bit 17, the rock and soil are cut. The broken part is carried to the hole opening through the annular gap between outer tube 12 and hole wall with flushing fluid. The unbroken part inside outer drill bit 17 enters inner tube 19 through clamp 18.

[0037] 5. Once the drilling depth is reached, stop drilling, turn off the flushing fluid, and then slowly raise drill pipe 1 to remove the coring device.

[0038] 6. After taking it out, place the outer tube 12 horizontally, disassemble the outer tube 12 connected to the upper pre-tightening connector 11 and the connecting seat 6, then disassemble the inner tube 19 and take out the core sample 35.

[0039] 7. Repeat the above process to enter the next cycle.

[0040] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A coring device, comprising a connector threadedly connected to a drill pipe, characterized in that, A buffer rubber is fixedly installed at the other end of the connector. The buffer rubber is frictionally connected to a connecting seat. The end of the connecting seat away from the buffer rubber is threaded to an upper pre-tightening joint. The upper pre-tightening joint is threaded to an outer tube. The other end of the outer tube is threaded to a lower pre-tightening joint. A pre-tightening support tube is provided inside the outer tube. The pre-tightening support tube is located between the upper and lower pre-tightening joints. The other end of the lower pre-tightening joint is threaded to an outer drill bit. The end of the connecting seat has a boss that extends into the pre-tightening support tube. A rotating shaft is rotatably mounted on the boss. An inner tube for core sample extraction is fixedly mounted on the rotating shaft. A clamp is provided at the end of the inner tube. The inner cavity of the inner tube communicates with the center hole of the outer drill bit. An annular cavity is provided between the pre-tightening support tube and the inner tube. The annular cavity is connected to the flushing hole on the outer drill bit. A central channel is provided through the connector, buffer rubber, and connecting seat. The connecting seat is provided with a connecting channel connecting the central channel and the annular cavity. A one-way valve is provided between the central channel and the connecting channel. By rotating the upper and lower pre-tightening joints, axial pre-tightening tension is applied to the outer tube. At this time, the outer tube is in a tensioned state, and the pre-tightening support tube is in a compressed state. Due to the radial constraint of the outer tube on the pre-tightening support tube, the pre-tightening support tube does not produce outward radial deformation and plays a supporting role for the outer tube. When the tensile force is greater than the axial load of the drill rod, the axial load of the drill rod is balanced with the pre-tension force of the outer tube, thus reducing the bending deformation of the outer tube.

2. The coring device according to claim 1, characterized in that, The outer surface of the connector is provided with several sets of protruding supports for pressing against the inner wall of the borehole.

3. The core sampling device according to claim 2, characterized in that, The extendable support includes a radial groove formed on the connecting seat, a telescopic block is radially slidably installed in the radial groove, a pressure plate is installed on the connecting seat by a clamping screw to restrict the telescopic block from sliding out of the radial groove, an expansion capsule is provided in the radial groove, the expansion capsule is connected to the central channel, and a force spring is provided in the radial groove to press the telescopic block against the expansion capsule.

4. The coring device according to claim 1, characterized in that, The connector is provided with a cavity, and the connector head is provided with a spline groove at one end of the cavity. The buffer rubber includes a rubber sleeve covering the outer periphery of the spline groove and an end face rubber fixed to the end face of the connector head by a fixing screw.

5. The coring device according to claim 1, characterized in that, The one-way valve includes a screw plug located at the end of the central channel on the connecting seat. A steel ball is provided in the central channel to isolate the central channel from the connecting channel. A compression spring is provided between the steel ball and the screw plug.

6. The coring device according to claim 1, characterized in that, An upper preload blade with a protruding cutting edge is installed on the outer periphery of the upper preload joint, and a lower preload blade with a protruding cutting edge is installed on the outer periphery of the lower preload joint.

7. The coring device according to claim 1, characterized in that, The rotating shaft is rotatably mounted on the bearing housing, which is threadedly connected to the boss. One end of the rotating shaft, away from the inner tube, extends out of the bearing housing and is fitted with a buffer nut. A buffer spring is provided between the buffer nut and the bearing housing.

8. The coring device according to any one of claims 1 to 7, characterized in that, The inner tube is threaded onto the end connector, which is threaded onto the rotating shaft. An adjusting nut is threaded onto the rotating shaft, and the adjusting nut abuts against the end connector.

9. The coring device according to claim 8, characterized in that, The end connector is fixedly connected to the upper connector of the semi-closed pipe, the inner pipe is threadedly connected to the upper connector of the semi-closed pipe, the other end of the inner pipe is threadedly connected to the lower connector of the semi-closed pipe, and the lower connector of the semi-closed pipe is threadedly connected to the clamp.

10. The coring device according to claim 9, characterized in that, A straightening ring is provided between the lower pre-tightening joint and the lower half-closed pipe joint. The straightening ring is located in the annular cavity and has several axially arranged through holes.

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