Reverse circulation drill rod pressure fan cover

Abstract

The invention belongs to the technical field of geological exploration and mine engineering, and discloses a reverse circulation drill rod pressure fan cover which comprises an upper connector, a first limiting ring, two packing rings and a second limiting ring are arranged outside the upper connector, a lower connector is installed at one end of the upper connector, and the lower connector is installed at the other end of the upper connector. One end of the lower joint away from the upper joint is provided with a connecting pipe through a connecting assembly; a large connector, a center pipe and a center pipe small connector are arranged in the upper connector, the large connector and the center pipe small connector are installed at the two ends of the center pipe respectively, and an elastic check ring for a hole is installed outside the large connector. A sealing ring is mounted in the central pipe small joint; in the working process, high-pressure gas is prevented from leaking towards the hole wall along the outer wall of the drill bit, it is ensured that all the gas returns along the inner wall of the inner drill rod, air flow circulates according to a set line, energy loss caused by turbulent flow is avoided, meanwhile, a stable negative pressure area is formed, and the rock debris capturing capacity is enhanced; the method has obvious advantages in the aspects of energy consumption control and drilling efficiency improvement.

Description

Technical Field

[0001] The invention belongs to the technical field of geological exploration and mining engineering, and in particular relates to a reverse circulation drill pipe air pressure cover. Background Art

[0002] Reverse circulation drilling (RCD) is an advanced drilling method that uses double-walled drill pipe to create a closed gas system. In this system, high-pressure gas is injected into the annular space between the inner and outer drill pipes, creating a negative pressure at the bottom of the hole. This negative pressure effectively draws cuttings up from the hole bottom and returns them to the surface at high speed through the inner drill pipe. This process forms a closed loop, ensuring continuous and efficient drilling.

[0003] Compared to traditional direct circulation drilling, reverse circulation drilling offers several advantages. First, it significantly improves cuttings removal efficiency. Because cuttings are returned directly to the surface via the inner drill pipe rather than being carried by the drilling fluid, they are removed more quickly from the hole bottom, maintaining a clean bottom. This not only increases drilling speed but also reduces drill bit wear and drilling accidents caused by cuttings accumulation.

[0004] The double-wall drill pipe structure primarily consists of an inner drill pipe, an outer drill pipe, and a drill bit. Most drill bits utilize a larger diameter than the outer drill pipe. Because the base and sides of these bits are covered with spherical carbide, during drilling, a significant amount of gas cannot be returned through the inner drill pipe as intended. Instead, it flows through the gaps between the drill bit's balls and into the space between the outer drill pipe and the hole wall. This high-pressure gas escapes through these gaps, causing a sharp drop in pressure and preventing effective reverse circulation. This directly weakens the reverse circulation driving force, hindering the upward return of cuttings, reducing drilling efficiency, and potentially even causing accidents such as hole wall collapse. Summary of the Invention

[0005] The object of the present invention is to provide a reverse circulation drill pipe air pressure cover to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a reverse circulation drill pipe pressure cover, comprising an upper joint, a first limit ring, a sealing ring, and a second limit ring are arranged on the outside of the upper joint, two sealing rings are provided, a lower joint is installed at one end of the upper joint, and a connecting pipe is installed at the end of the lower joint away from the upper joint through a connecting assembly;

[0007] A large joint, a central tube and a small central tube joint are provided inside the upper joint. The large joint and the small central tube joint are respectively installed at both ends of the central tube. An elastic retaining ring for a hole is installed outside the large joint.

[0008] During operation, the high-pressure gas is blocked from leaking out along the outer wall of the drill bit to the hole wall, ensuring that all the gas is returned along the inner wall of the inner drill pipe, so that the air flow circulates along the specified route, avoiding energy loss caused by turbulence, and forming a stable negative pressure area at the same time, thereby enhancing the ability to capture rock cuttings. It has obvious advantages in energy consumption control and drilling efficiency improvement.

[0009] As a further technical solution of the present invention, a sealing ring is installed inside the small central tube joint.

[0010] As a further technical solution of the present invention, the connecting assembly includes a card block embedded in the lower joint, the card blocks are evenly distributed in a circular array, a spring is connected between each card block and the lower joint, and the top of each card block is embedded in the inner wall of the card slot, and the card slot is opened on the inner wall of the connecting pipe.

[0011] During installation, plug the lower connector into the connecting pipe. When the card block slides to one side of the card slot, the spring releases the elastic potential energy to push the card block into the inside of the card slot, completing the plug-in.

[0012] The above-mentioned connection method avoids the problem of traditional threaded connection, which requires sufficient space for rotation to complete tightening and may be limited in narrow wellheads or automated drilling rigs. This connection method not only has low installation space requirements but is also convenient and fast.

[0013] As a further technical solution of the present invention, the card block is slidably connected to the card slot.

[0014] When plugging in, there is no need to adjust the position of the lower joint and the connecting pipe, just plug in and install it directly. The installation method is simple and convenient.

[0015] As a further technical solution of the present invention, a rotating ring is installed on the outside of the lower joint, and guide plates are fixedly installed on the inner wall of the rotating ring, and the guide plates are evenly distributed in a ring array;

[0016] A fixing plate is provided on one side of the guide plate, and the fixing plate is fixedly installed on one side of the clamping block.

[0017] When disassembling, rotate the rotating ring, and the rotation of the rotating ring drives the rotation of the guide plate. When the guide plate rotates, it contacts the fixed plate and presses it down. The movement of the fixed plate drives the clamping block to slide out from the inner wall of the clamping groove, and then separates the lower joint and the connecting pipe, making it easier to disassemble;

[0018] Both ends of the guide plate are tilted so that the fixed plate can be moved downward when the rotating ring is rotated forward or backward to complete the disassembly.

[0019] As a further technical solution of the present invention, the guide plate is rotatably mounted on the inner wall of the lower joint.

[0020] As a further technical solution of the present invention, the side wall of the fixed plate is evenly installed with indication plates in a ring array, and the indication plates are arranged on one side of the guide plate.

[0021] The indicator plate is located on one side of the guide plate, which makes it easy for workers to understand the position of the guide plate from outside the device and assist in completing the disassembly.

[0022] As a further technical solution of the present invention, the inner wall of the connecting pipe is provided with an O-ring, and the outer wall of the O-ring is fixedly installed with a connecting plate, and the connecting plates are evenly distributed in an annular array. A guide ring is provided on the top of the connecting plate, and the side wall of the guide ring is evenly installed with connecting shafts in an annular array, and the connecting shaft is slidably installed on the inner wall of the connecting pipe.

[0023] The O-ring is used to seal the lower joint and the connecting pipe during installation. When the lower joint and the connecting pipe are plugged in during installation, the rotating ring approaches one side of the connecting pipe to push the connecting shaft inward. The movement of the connecting shaft drives the movement of the guide ring. When the guide ring moves, it presses the connecting plate downward. When the connecting plate moves, it squeezes the O-ring, so that the inner wall of the O-ring fits the outer wall of the lower joint, thereby improving the sealing between the connecting pipe and the lower joint. Under the combined action of drill pipe rotation and axial impact, the O-ring reduces friction and wear through its self-lubricating properties, maintaining a long-term sealing effect.

[0024] As a further technical solution of the present invention, the guide ring is slidably installed inside the connecting pipe, and a first tension spring is connected between the guide ring and the connecting pipe.

[0025] During the installation process, when the guide ring moves toward the side away from the connecting shaft, the first tension spring deforms to store elastic potential energy;

[0026] After disassembly, the first tension spring releases elastic potential energy to cause the guide ring to move to a side away from the connecting plate and reset.

[0027] As a further technical solution of the present invention, a limiting shaft is fixedly installed on the top of the connecting plate, the limiting shaft is slidably installed inside the connecting pipe, and a second tension spring is sleeved on the outside of the limiting shaft.

[0028] During the installation process, when the connecting plate moves downward, the second tension spring deforms to store elastic potential energy;

[0029] During disassembly, after the guide ring is removed from the top of the connecting plate, the elastic potential energy is released by the second tension spring to move the O-ring back to its original position, making it easier to separate the lower joint from the connecting pipe.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. The present invention uses multiple structures to coordinate and cooperate. When working, it blocks the high-pressure gas from leaking out along the outer wall of the drill bit to the hole wall, ensures that all the gas returns along the inner wall of the inner drill pipe, and makes the air flow circulate along the specified route, avoiding energy loss caused by turbulence. At the same time, a stable negative pressure area is formed, which enhances the ability to capture rock cuttings. It has obvious advantages in energy consumption control and drilling efficiency improvement.

[0032] 2. The present invention is provided with a connection component. During installation, the lower joint is plugged into the connecting pipe. When the clamping block slides to one side of the clamping slot, the elastic potential energy is released by the spring to push the clamping block into the interior of the clamping slot, thereby completing the plugging. The above-mentioned connection method avoids the problem that the traditional threaded connection method requires sufficient space for rotation to complete tightening, which may be limited in narrow wellheads or automated drilling rigs. This connection method not only has low installation space requirements but is also convenient and quick.

[0033] 3. The present invention seals the lower joint and the connecting pipe through the O-ring during installation. During the installation process, when the lower joint and the connecting pipe are plugged in, the rotating ring approaches one side of the connecting pipe to push the connecting shaft inward. The movement of the connecting shaft drives the movement of the guide ring. When the guide ring moves, it presses the connecting plate downward. When the connecting plate moves, it squeezes the O-ring, so that the inner wall of the O-ring fits with the outer wall of the lower joint, thereby improving the sealing between the connecting pipe and the lower joint; and under the combined action of the drill pipe rotation and axial impact, the O-ring reduces friction and wear through its self-lubricating characteristics, maintaining a long-term sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0035] Figure 2 It is a schematic cross-sectional view of the overall structure of the present invention;

[0036] Figure 3 It is a sectional side view of the overall structure of the present invention;

[0037] Figure 4 This is a schematic cross-sectional view of the lower joint structure of the present invention;

[0038] Figure 5 This is a schematic cross-sectional view of the structure of the lower joint and the connecting pipe of the present invention;

[0039] Figure 6 This is a schematic cross-sectional view of the connecting pipe structure of the present invention;

[0040] Figure 7 For the present invention Figure 6 A schematic diagram of the structure at center A;

[0041] Figure 8 This is a structural diagram of the rotating ring of the present invention;

[0042] Figure 9 Schematic diagram of gas flow in the present invention.

[0043] In the figure: 1. Upper joint; 2. Limiting ring 1; 3. Sealing ring; 4. Limiting ring 2; 5. Lower joint; 6. Large joint; 7. Center tube; 8. Small joint of center tube; 9. Elastic retaining ring for hole; 10. Sealing ring; 11. Connecting pipe; 12. Block; 13. Slot; 14. Spring; 15. Fixed plate; 16. Rotating ring; 17. Guide plate; 18. Schematic board; 19. Connecting shaft; 20. Guide ring; 21. Connecting plate; 22. O-ring; 23. First tension spring; 24. Limiting shaft; 25. Second tension spring. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] like Figures 1 to 9 As shown, in an embodiment of the present invention, a reverse circulation drill pipe pressure cover includes an upper joint 1, a limit ring 2, a sealing ring 3 and a limit ring 4 are provided on the outside of the upper joint 1, two sealing rings 3 are provided, a lower joint 5 is installed at one end of the upper joint 1, and a connecting pipe 11 is installed at the end of the lower joint 5 away from the upper joint 1 through a connecting assembly;

[0046] A large joint 6, a central tube 7 and a small central tube joint 8 are provided inside the upper joint 1. The large joint 6 and the small central tube joint 8 are respectively installed at both ends of the central tube 7. A hole elastic retaining ring 9 is installed outside the large joint 6.

[0047] The upper joint 1 is specifically made of 40Cr material, 6.128kg;

[0048] The limiting ring 2 is made of 40Cr material and weighs 0.642 kg.

[0049] The sealing ring 3 is specifically a 110 sealing ring, made of nylon material, 0.127 kg;

[0050] Limiting ring 2 4 is made of conventional material, 0.083kg;

[0051] The lower joint 5 is specifically made of 40Cr material, 3.566kg;

[0052] The large joint 6 is made of 40Cr material, weighs 0.061kg, and is compatible with the 89 double-arm drill pipe.

[0053] The central tube 7 is specifically made of aluminum 7 series material, 0.650 kg;

[0054] The central tube small joint 8 is specifically made of 40Cr material, 0.919kg;

[0055] The hole elastic retaining ring 9 is specifically the elastic retaining ring GB893.1-86-75, steel material, 0.020kg, and is universal with the 89 double-arm drill pipe;

[0056] During operation, the high-pressure gas is blocked from leaking out along the outer wall of the drill bit to the hole wall, ensuring that all the gas is returned along the inner wall of the inner drill pipe, so that the air flow circulates along the specified route, avoiding energy loss caused by turbulence, and forming a stable negative pressure area at the same time, thereby enhancing the ability to capture rock cuttings. It has obvious advantages in energy consumption control and drilling efficiency improvement.

[0057] like Figure 1 , pictures and Figure 3 As shown, a sealing ring 10 is installed inside the central pipe small joint 8.

[0058] The sealing ring 10 is made of conventional material, weighs 0.007 kg, and is compatible with the 89 double-arm drill pipe.

[0059] The installation of a sealing ring 10 inside the small central tube joint 8 is the core design to ensure the high-pressure sealing performance of the system. Through its own elastic deformation, it can automatically adjust the contact surface within the error range of 0.1-0.3mm;

[0060] Furthermore, the sealing ring 10 maintains a continuous pre-tightening force of 10-15N under vibration conditions to avoid the generation of gaps.

[0061] like Figures 1 to 9 As shown, the connecting assembly includes a card block 12 embedded in the lower joint 5, and the card blocks 12 are evenly distributed in a circular array. A spring 14 is connected between each card block 12 and the lower joint 5. The top of each card block 12 is embedded in the inner wall of the card slot 13, and the card slot 13 is opened on the inner wall of the connecting pipe 11.

[0062] During installation, plug the lower connector 5 into the connecting pipe 11. When the block 12 slides to one side of the slot 13, the spring 14 releases the elastic potential energy to push the block 12 into the slot 13, completing the plugging.

[0063] The above connection method avoids the problem of traditional threaded connection, which requires sufficient space for rotation to complete tightening and may be limited in narrow wellheads or automated drilling rigs;

[0064] Threaded installation relies on manual or mechanical torque application, but in actual operation, the torque value fluctuation range can reach ±30% (for example, the target torque is 100N·m, and the actual torque may be 70-130N·m);

[0065] Especially under vibration or thermal cycle conditions, the pre-tightening force of the threaded connection will gradually decay due to factors such as material creep and micro-wear, resulting in loose connections. The connection method of embedding the block 12 in the slot 13 not only has low installation space requirements, but is also convenient and quick.

[0066] like Figures 1 to 7 As shown, the clamping block 12 and the clamping slot 13 are slidably connected.

[0067] The card slot 13 is arranged in a ring shape;

[0068] The continuity of the annular groove 13 ensures that when the lower connector 5 and the connecting pipe 11 are plugged in at any angle, the block 12 can automatically slide into the groove without manual rotation to adjust the angle (traditional threaded connections require 8-10 turns to align the threads); when plugging in, it can be directly plugged in and installed, and the installation method is simple and convenient.

[0069] The clamping groove 13 is 360° closed ring along the circumferential direction of the lower joint 5 or the connecting pipe 11, without a starting point or an end point, thus avoiding the stress concentration problem caused by the segmented design of the traditional clamping groove.

[0070] like Figures 1 to 8 As shown, a rotating ring 16 is installed on the outside of the lower joint 5, and a guide plate 17 is fixedly installed on the inner wall of the rotating ring 16. The guide plates 17 are evenly distributed in a ring array;

[0071] A fixing plate 15 is provided on one side of the guide plate 17 , and the fixing plate 15 is fixedly mounted on one side of the clamping block 12 .

[0072] During disassembly, the rotating ring 16 is rotated. The rotation of the rotating ring 16 drives the rotation of the guide plate 17. When the guide plate 17 rotates, it contacts the fixed plate 15 and presses it downward. The movement of the fixed plate 15 drives the clamping block 12 to slide out from the inner wall of the clamping groove 13, and then the lower joint 5 and the connecting pipe 11 are separated, making it easier to disassemble.

[0073] Both ends of the guide plate 17 are tilted so that the fixing plate 15 can be moved downward when the rotating ring 16 is rotated forward or backward to complete the disassembly.

[0074] like Figure 4 、 Figure 5 and Figure 6 As shown, the guide plate 17 is rotatably mounted on the inner wall of the lower joint 5 .

[0075] like Figure 4 、 Figure 5 、 Figure 6 and Figure 8 As shown, the side wall of the fixed plate 15 is evenly installed with indicator plates 18 in a circular array, and the indicator plates 18 are arranged on one side of the guide plate 17.

[0076] The indication plate 18 is located on one side of the guide plate 17 , so that the staff can understand the position of the guide plate 17 from outside the device and assist in completing the disassembly.

[0077] like Figures 1 to 9 As shown, the inner wall of the connecting tube 11 is provided with an O-ring 22, and the outer wall of the O-ring 22 is fixedly installed with a connecting plate 21, and the connecting plates 21 are evenly distributed in a circular array. A guide ring 20 is provided on the top of the connecting plate 21, and the side wall of the guide ring 20 is evenly installed with connecting shafts 19 in a circular array. The connecting shaft 19 is slidably installed on the inner wall of the connecting tube 11.

[0078] The side of the guide ring 20 away from the connecting shaft 19 is tilted;

[0079] The O-ring 22 is used to seal the lower joint 5 and the connecting pipe 11 during installation. During installation, when the lower joint 5 and the connecting pipe 11 are plugged in, the rotating ring 16 approaches one side of the connecting pipe 11 to push the connecting shaft 19 inward. The movement of the connecting shaft 19 drives the movement of the guide ring 20. When the guide ring 20 moves, it presses the connecting plate 21 downward. When the connecting plate 21 moves, it squeezes the O-ring 22, so that the inner wall of the O-ring 22 fits against the outer wall of the lower joint 5, thereby improving the sealing between the connecting pipe 11 and the lower joint 5.

[0080] The air hood needs to withstand the compressed air pressure (usually 1.0-1.5 MPa). The O-ring 22 fills the gap between the lower joint 5 and the connecting pipe 11 through elastic deformation to form a high-pressure barrier.

[0081] Under the combined effects of drill pipe rotation (rotation speed 80-120 rpm) and axial impact (impact force up to 50 kN), the O-ring 22 reduces friction and wear through its self-lubricating properties (such as filling with polytetrafluoroethylene) to maintain a long-term sealing effect.

[0082] like Figures 1 to 9 As shown, the guide ring 20 is slidably installed inside the connecting pipe 11 , and a first tension spring 23 is connected between the guide ring 20 and the connecting pipe 11 .

[0083] During the installation process, when the guide ring 20 moves toward the side away from the connecting shaft 19, the first tension spring 23 deforms to store elastic potential energy;

[0084] After disassembly, the first tension spring 23 releases elastic potential energy to cause the guide ring 20 to move to a side away from the connecting plate 21 and reset.

[0085] like Figures 1 to 9 As shown, a limit shaft 24 is fixedly mounted on the top of the connecting plate 21 , the limit shaft 24 is slidably mounted inside the connecting tube 11 , and a second tension spring 25 is sleeved on the outside of the limit shaft 24 .

[0086] During the installation process, when the connecting plate 21 moves downward, the second tension spring 25 deforms and stores elastic potential energy;

[0087] During disassembly, after the guide ring 20 is removed from the top of the connecting plate 21 , the elastic potential energy is released by the second tension spring 25 to move the O-ring 22 back to its original position, thereby facilitating the separation of the lower connector 5 from the connecting pipe 11 .

[0088] Working principle:

[0089] During installation, plug the lower connector 5 into the connecting pipe 11. When the block 12 slides to one side of the slot 13, the spring 14 releases the elastic potential energy to push the block 12 into the slot 13, completing the plugging.

[0090] At the same time, the rotating ring 16 approaches one side of the connecting pipe 11 to push the connecting shaft 19 inward. The movement of the connecting shaft 19 drives the movement of the guide ring 20. When the guide ring 20 moves, it presses the connecting plate 21 downward. When the connecting plate 21 moves, it squeezes the O-ring 22, so that the inner wall of the O-ring 22 fits against the outer wall of the lower joint 5, thereby improving the sealing between the connecting pipe 11 and the lower joint 5.

[0091] During operation, the high-pressure gas is blocked from leaking out along the outer wall of the drill bit to the hole wall, ensuring that all the gas is returned along the inner wall of the inner drill pipe, so that the air flow circulates along the specified route, avoiding energy loss caused by turbulence, and forming a stable negative pressure area at the same time, thereby enhancing the ability to capture rock cuttings. It has obvious advantages in energy consumption control and drilling efficiency improvement.

[0092] During disassembly, the rotating ring 16 is rotated. The rotation of the rotating ring 16 drives the rotation of the guide plate 17. When the guide plate 17 rotates, it contacts the fixed plate 15 and presses it downward. The movement of the fixed plate 15 drives the clamping block 12 to slide out from the inner wall of the clamping groove 13, and then the lower connector 5 and the connecting pipe 11 are separated.

[0093] At the same time, the first tension spring 23 releases elastic potential energy to move the guide ring 20 to the side away from the connecting plate 21 and reset. After the guide ring 20 is removed from the top of the connecting plate 21, the second tension spring 25 releases elastic potential energy to move the O-ring 22 and reset it, making it easier to separate the lower joint 5 from the connecting pipe 11.

[0094] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A reverse circulation drill pipe pressure cover, comprising an upper joint (1), characterized in that: The outer portion of the upper joint (1) is provided with a limiting ring (2), a sealing ring (3) and a limiting ring (4), two sealing rings (3) are provided, a lower joint (5) is installed at one end of the upper joint (1), and a connecting pipe (11) is installed at the end of the lower joint (5) away from the upper joint (1) through a connecting assembly; A large joint (6), a central tube (7) and a small central tube joint (8) are provided inside the upper joint (1); the large joint (6) and the small central tube joint (8) are respectively installed at two ends of the central tube (7); and a hole elastic retaining ring (9) is installed outside the large joint (6).

2. The reverse circulation drill pipe air pressure cover according to claim 1, characterized in that: A sealing ring (10) is installed inside the central tube small joint (8).

3. The reverse circulation drill pipe air pressure cover according to claim 1, characterized in that: The connecting assembly comprises a card block (12) embedded in the interior of the lower joint (5), the card blocks (12) being evenly distributed in a ring array, a spring (14) being connected between each card block (12) and the lower joint (5), the top of each card block (12) being embedded in the inner wall of a card slot (13), and the card slot (13) being opened on the inner wall of the connecting pipe (11).

4. The reverse circulation drill pipe air pressure cover according to claim 3, characterized in that: The card block (12) is slidably connected to the card slot (13).

5. The reverse circulation drill pipe air pressure cover according to claim 1, characterized in that: A rotating ring (16) is installed on the outside of the lower joint (5), and a guide plate (17) is fixedly installed on the inner wall of the rotating ring (16), and the guide plates (17) are evenly distributed in a ring array; A fixing plate (15) is provided on one side of the guide plate (17), and the fixing plate (15) is fixedly mounted on one side of the clamping block (12).

6. The reverse circulation drill pipe air pressure cover according to claim 5, characterized in that: The guide plate (17) is rotatably mounted on the inner wall of the lower joint (5).

7. The reverse circulation drill pipe air pressure cover according to claim 5, characterized in that: The side wall of the fixed plate (15) is evenly mounted with a signal plate (18) in a circular array, and the signal plate (18) is arranged on one side of the guide plate (17).

8. The reverse circulation drill pipe air pressure cover according to claim 1, characterized in that: The inner wall of the connecting pipe (11) is provided with an O-type sealing ring (22), and the outer wall of the O-type sealing ring (22) is fixedly installed with a connecting plate (21), and the connecting plates (21) are evenly distributed in an annular array. A guide ring (20) is provided on the top of the connecting plate (21), and the side wall of the guide ring (20) is evenly installed with a connecting shaft (19) in an annular array. The connecting shaft (19) is slidably installed on the inner wall of the connecting pipe (11).

9. The reverse circulation drill pipe air pressure cover according to claim 8, characterized in that: The guide ring (20) is slidably mounted inside the connecting pipe (11), and a first tension spring (23) is connected between the guide ring (20) and the connecting pipe (11).

10. The reverse circulation drill pipe air pressure cover according to claim 8, characterized in that: A limiting shaft (24) is fixedly mounted on the top end of the connecting plate (21), the limiting shaft (24) is slidably mounted inside the connecting tube (11), and a second tension spring (25) is sleeved on the outside of the limiting shaft (24).

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