A detachable float collar and float shoe

Abstract

The present invention relates to the technical field of cementing engineering tools, and discloses a non-disengaging float collar and float shoe, which includes a float collar, a casing and a float shoe. The float collar, the casing and the float shoe are arranged in sequence from top to bottom. The float collar includes a first pipe body, a first anti-disengagement connecting piece and a first one-way flow guiding piece. The first one-way flow guiding piece is arranged in the first pipe body and is used to prevent the cement slurry from flowing back into the casing. The first anti-disengagement connecting piece is respectively arranged at the upper and lower ends of the first pipe body. The design of the first one-way flow guiding piece and the second one-way flow guiding piece in this application ensures that the cement slurry can flow forward into the annular space between the casing and the wellbore during the cementing process, and effectively prevents the cement slurry from flowing back into the casing, which helps to maintain the stability and sealing performance of the casing. The present invention has the characteristics of strong practicability and strong reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of cementing engineering tools, and particularly to a non - disengaging float collar and float shoe. Background Art

[0002] In the oil and gas drilling industry, the cementing operation is a key step to ensure the wellbore stability and subsequent production safety. During the cementing process, the float collar and float shoe, as two important components, mainly guide the casing to be smoothly lowered into the wellbore and prevent the cement slurry from flowing back into the casing interior, thus ensuring the cementing quality. However, traditional float collars and float shoes have some technical defects, which affect their performance and reliability.

[0003] In the early design, although the choke ring (support ring) can limit the position of the cementing plug and ensure the cementing quality at the bottom of the production casing, the welding time of the "slap" is relatively long, which affects the overall efficiency of running the casing, and at the same time increases the risk of insecure connection. If the lower - string structure of the casing string, such as the positions of the float collar and float shoe, is offset, it will lead to the problem of more cement on one side and less on the other side during cementing, thus affecting the overall cementing effect. In addition, when drilling out the valve core inside the float collar and float shoe after cementing, due to the poor drillability of its internal structure or poor cement bonding quality at the bottom of the casing, it is easy to cause the overall inversion and disengagement of the float collar and float shoe, which not only increases the treatment difficulty but also may lead to serious downhole complex faults.

[0004] Recently, the invention patent with the publication number CN118327509B proposed a float collar and float shoe for cementing. The device includes a float collar and float shoe body, and a sealing seat is fixedly connected to the inner wall of the float collar and float shoe body. The outer wall of the first connecting shaft is rotatably connected to a telescopic rod, and a second support block is fixedly connected to the upper surface of the chassis. Although this design improves the functionality of the equipment by adding multiple mechanical components, in actual application, this kind of float collar and float shoe is only connected to the casing through threads, and the tightness and reliability are relatively poor, and the problem of insecure connection is not completely solved. This limitation may cause the connection between the float collar and float shoe and the casing to become loose or fall off in a high - pressure or high - vibration environment, thus affecting the safety and effectiveness of the cementing operation. Therefore, it is necessary to design a non - disengaging float collar and float shoe with strong practicality and reliability. Summary of the Invention

[0005] The purpose of the present invention is to provide a non - disengaging float collar and float shoe to solve the problems raised in the above - mentioned background art.

[0006] To solve the above technical problems, the present invention provides the following technical solution: a detachable floating collar and floating shoe, including a floating collar, a casing, and a floating shoe. The floating collar, the casing, and the floating shoe are arranged in sequence from top to bottom. The floating collar includes a first pipe body, a first anti-detachment connecting piece, and a first one-way flow guiding piece. The first one-way flow guiding piece is arranged inside the first pipe body and is used to prevent the cement slurry from flowing back into the casing. The first anti-detachment connecting piece is respectively arranged at the upper and lower ends of the first pipe body and is used for anti-detachment connection with the casing. The floating shoe includes a second pipe body, a guiding cap, a second anti-detachment connecting piece, and a second one-way flow guiding piece. The second one-way flow guiding piece has the same structure and similar function as the first one-way flow guiding piece, and is used to help the casing smoothly enter the wellbore and prevent the fluid in the well from entering the inside of the casing. The second anti-detachment connecting piece is arranged at the upper end of the floating shoe. The second anti-detachment connecting piece has the same structure and function as the first anti-detachment connecting piece. The guiding cap is integrally formed at the lower end of the second pipe body.

[0007] According to the above technical solution, the first one-way flow guiding piece includes a first flow blocking plate, a first sealing ball, a first ball rod, a first spring, and a flower basket. The first flow blocking plate is arranged inside the first pipe body. The inside of the first flow blocking plate is hollow and an opening one is formed through the lower end. The flower basket is fixedly installed at the central position inside the opening one. The first ball rod is movably installed at the middle position of the flower basket. The first sealing ball is fixedly installed at the top end of the first ball rod. The first spring is sleeved outside the first ball rod. The upper end of the first spring abuts against the first sealing ball and the lower end abuts against the flower basket. An opening two is formed through the central position of the upper end of the first flow blocking plate. A spherical sealing groove one is formed at the lower end of the opening two and corresponds to the first sealing ball.

[0008] According to the above technical solution, the first one-way flow guiding piece further includes a second flow blocking plate, a second sealing ball, a second spring, and a second ball rod. The second flow blocking plate is fixedly installed inside the first pipe body. The second flow blocking plate is arranged above the first flow blocking plate. The second ball rod is movably installed through the edge position of the upper end of the first flow blocking plate. The second ball rods are arranged in a circumferential array at the upper end of the first flow blocking plate. The second sealing ball is fixedly installed at the top of the second ball rod. The second spring is sleeved outside the second ball rod. The upper end of the second spring abuts against the second sealing ball and the lower end abuts against the first flow blocking plate. An opening three is formed through the upper end of the second flow blocking plate. The opening threes are arranged in a circumferential array on the second flow blocking plate. A spherical sealing groove two is formed at the lower end of the opening three and corresponds to the second sealing ball one by one.

[0009] According to the above technical solution, the diameter of the first opening is greater than that of the second opening. The flower basket includes a central fixing block and a connecting rod. The central fixing block is arranged at the central position of the first opening. The central fixing block and the first flow blocking plate are fixedly connected through the connecting rod. The connecting rods are arranged in a circumferential array. The diameter of the second opening is greater than that of the third opening.

[0010] According to the above technical solution, the first flow blocking plate is movably installed in the first pipe body, and the outer wall surface of the first flow blocking plate is in sliding contact with the inner wall surface of the first pipe body. A placement groove is formed in one side wall of the first flow blocking plate. The placement grooves are arranged in a circumferential array around the first opening. A pushing member is arranged in the placement groove and is used to push the first flow blocking plate towards the second flow blocking plate after being pressed, so as to improve the sealing performance of the third opening. A rubber sealing ring is embedded and installed on the upper side wall of the first flow blocking plate.

[0011] According to the above technical solution, the pushing member includes a third spring, a pushing block, a pushing head and a rack. One end of the placement groove adjacent to the first opening is fixedly installed with the third spring. The telescopic end of the third spring is fixedly installed with the pushing block. The end of the pushing block is fixedly installed with the pushing head. A first sliding contact surface is formed on the pushing head. A strip-shaped groove is formed in the inner wall of the first pipe body. The strip-shaped grooves and the placement grooves are arranged in one-to-one correspondence. The rack is fixedly installed in the strip-shaped groove. A second sliding contact surface corresponding to the first sliding contact surface is formed on the rack. The second sliding contact surface and the first sliding contact surface are in sliding contact.

[0012] According to the above technical solution, the first anti-disconnection connecting member includes a connecting pipe and an external thread connecting ring. The connecting pipe, the first pipe body, the sleeve and the second pipe body have the same outer diameter. The external thread connecting rings are symmetrically and fixedly installed at the upper and lower ends of the connecting pipe. The connecting pipe, the external thread connecting ring, the first pipe body, the sleeve and the second pipe body have the same inner diameter. Inner thread grooves are respectively formed at the upper and lower ends of the first pipe body and the sleeve and at the upper end of the second pipe body. The inner thread grooves and the external thread connecting rings are arranged in correspondence, and the external thread connecting rings are threadedly connected in the corresponding inner thread grooves.

[0013] According to the above technical solution, an anti-disconnection positioning groove is formed in the connecting pipe. The anti-disconnection positioning grooves are arranged in a circumferential array in the connecting pipe. A multi-point locking member is arranged in the anti-disconnection positioning groove and is used for anti-disconnection fixation of the float collar and the float shoe.

[0014] According to the above technical solution, the multi-point locking member includes a locking block, a fixing plate, a first rotating rod, a first bevel gear, a second rotating rod, a second bevel gear and a handle. The locking blocks are symmetrically and movably installed in the anti-disengagement positioning grooves. A locking head is fixedly installed at one end of the locking block away from each other. Locking grooves are evenly distributed circumferentially at the upper and lower ends of the first pipe body and the sleeve and at the upper end of the second pipe body. The locking grooves are arranged corresponding to the locking heads. The locking heads penetrate through the connecting pipe and are located in the corresponding locking grooves. The fixing plates are symmetrically and fixedly installed in the anti-disengagement positioning grooves. The distance between the fixing plates is smaller than the distance between the locking blocks. The first rotating rod is movably installed in the fixing plates. The first bevel gears are fixedly installed at opposite ends of the first rotating rod. The end of the first rotating rod away from each other is threadedly connected to the corresponding locking block. The second rotating rod is movably installed outside the anti-disengagement positioning groove. One end of the second rotating rod extends into the anti-disengagement positioning groove and the second bevel gear is fixedly installed thereon. The second bevel gears are respectively meshed and connected with the corresponding first bevel gears. The other end of the second rotating rod penetrates through the connecting pipe and is provided with the handle.

[0015] According to the above technical solution, the handle includes a connecting handle and a screwing plate. The other end of the second rotating rod is movably connected to the connecting handle. The screwing plate is fixedly installed at the end of the connecting handle. A limiting block is fixedly installed on one side of the second rotating rod. A limiting groove corresponding to the limiting block is formed in the connecting handle. The limiting block is movably installed in the limiting groove. An embedding groove is formed in the side wall of the connecting pipe. The embedding grooves are arranged corresponding to the handles one by one. The screwing plate is embedded and installed in the corresponding embedding groove. The outer wall surface of the screwing plate is flush with the outer wall surface of the connecting pipe. Arc-shaped grooves are symmetrically formed in the embedding groove. Hand-picking grooves are symmetrically formed in the side wall of the screwing plate.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0017] (1) Prevent reverse flow of cement slurry: The designs of the first one-way flow guiding member and the second one-way flow guiding member ensure that the cement slurry can flow forward into the annular space between the casing and the well wall during the cementing process and effectively prevent the reverse flow of the cement slurry back into the casing, which helps to maintain the stability and sealing performance of the casing;

[0018] (2) Enhance sealing performance: The dual sealing mechanism (the first-stage sealing system composed of the first sealing ball, the first spring, etc. and the second-stage sealing system composed of the second flow blocking plate and the second sealing ball) significantly improves the safety and reliability of the system and can ensure good sealing effect even in high-pressure or high-vibration environments;

[0019] (3) Improve installation stability: The design of the anti-disengagement connector I and the anti-disengagement connector II enables a firm connection between the float collar and the float shoe and the casing, avoiding loosening or detachment of the equipment due to vibration or impact, thus ensuring the integrity of the entire system;

[0020] (4) Ability to adapt to complex environments: The propulsion member can automatically adjust the position of the choke plate I under high-pressure conditions, enhancing the sealing effect and adapting to complex downhole working conditions;

[0021] (5) Simplify the installation process: The design consistency and component universality (such as the same anti-disengagement connector and one-way flow guide member structure) simplify the installation process, reduce the risk of misusing different types of connectors, and reduce manufacturing costs and improve production efficiency;

[0022] (6) Redundant design increases system reliability: The additional locking slots provided by the multi-point locking member provide redundant protection for the system, increasing the reliability and stability of the system. Even if some locking heads or locking slots fail, the system can still be locked through other available locking slots;

[0023] (7) Facilitate operation and maintenance: The embedded design and flush-mounted handle not only enhance the aesthetic appearance but also increase the safety of use, reducing the possibility of accidental collision of external objects with the screwing plate and reducing the risk of unexpected unlocking. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0025] Figure 1 is a three-dimensional schematic diagram of the present invention;

[0026] Figure 2 is an exploded schematic diagram of the present invention;

[0027] Figure 3 is a three-dimensional schematic diagram of the float collar of the present invention;

[0028] Figure 4 is a first partial three-dimensional schematic diagram of the float collar of the present invention;

[0029] Figure 5 is a second partial three-dimensional schematic diagram of the float collar of the present invention;

[0030] Figure 6 is a three-dimensional schematic diagram of the one-way flow guide member I of the present invention;

[0031] Figure 7 is a first partial three-dimensional schematic diagram of the one-way flow guide member I of the present invention;

[0032] Figure 8 It is the second partial three-dimensional schematic diagram of the one-way flow guiding member I of the present invention;

[0033] Figure 9 It is the three-dimensional schematic diagram of the floating shoe of the present invention;

[0034] Figure 10 It is the partial three-dimensional schematic diagram of the floating shoe of the present invention;

[0035] Figure 11 It is the present invention Figure 4 The enlarged schematic diagram at position A in;

[0036] Figure 12 It is the present invention Figure 4 The enlarged schematic diagram at position B in;

[0037] Figure 13 It is the present invention Figure 5 The enlarged schematic diagram at position C in;

[0038] In the figure: 1 - casing, 2 - pipe body I, 21 - strip-shaped groove, 3 - anti-disconnection connecting member I, 31 - connecting pipe, 311 - anti-disconnection positioning groove, 312 - embedding groove, 313 - arc-shaped groove, 32 - external thread connecting ring, 33 - internal thread groove, 4 - one-way flow guiding member I, 41 - flow blocking plate I, 411 - opening I, 412 - opening II, 413 - spherical sealing groove I, 414 - placing groove, 415 - rubber sealing ring, 42 - sealing ball I, 43 - ball rod I, 44 - spring I, 45 - flower basket, 451 - central fixing block, 452 - connecting rod, 46 - flow blocking plate II, 461 - opening III, 462 - spherical sealing groove II, 47 - sealing ball II, 48 - spring II, 49 - ball rod II, 5 - pipe body II, 6 - guiding cap, 7 - pushing member, 71 - spring III, 72 - pushing block, 73 - pushing head, 731 - sliding contact surface I, 74 - rack, 741 - sliding contact surface II, 8 - multi-point locking member, 81 - locking block, 811 - locking head, 82 - fixing plate, 83 - rotating rod I, 84 - bevel gear I, 85 - rotating rod II, 851 - limiting block, 86 - bevel gear II, 87 - handle, 871 - connecting handle, 872 - screwing plate, 88 - locking groove. Detailed implementation manners

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0040] Please refer to Figures 1-13, the present invention provides a technical solution: a detachable floating collar and floating shoe, including a floating collar, a casing 1 and a floating shoe. The floating collar, the casing 1 and the floating shoe are arranged in sequence from top to bottom. The floating collar includes a pipe body 1 2, a detachable connecting piece 1 3 and a one-way flow guiding piece 1 4. The one-way flow guiding piece 1 4 is arranged inside the pipe body 1 2 and is used to prevent the cement slurry from flowing back into the casing 1. The detachable connecting piece 1 3 is respectively arranged at the upper and lower ends of the pipe body 1 2 and is used for detachable connection with the casing 1. The floating shoe includes a pipe body 2 5, a guiding cap 6, a detachable connecting piece 2 and a one-way flow guiding piece 2. The one-way flow guiding piece 2 has the same structure and similar function as the one-way flow guiding piece 1 4, and is used to help the casing 1 smoothly enter the wellbore and prevent the fluid in the well from entering the inside of the casing 1. The detachable connecting piece 2 is arranged at the upper end of the floating shoe. The detachable connecting piece 2 has the same structure and the same function as the detachable connecting piece 1 3. The guiding cap 6 is integrally formed at the lower end of the pipe body 2 5;

[0041] This application includes a floating collar, a casing 1 and a floating shoe. The casing 1 is a common basic structure in this technical field and will not be elaborated here. The floating collar includes a pipe body 1 2, a detachable connecting piece 1 3 and a one-way flow guiding piece 1 4. The floating shoe includes a pipe body 2 5, a guiding cap 6, a detachable connecting piece 2 and a one-way flow guiding piece 2. The pipe body 1 2 and the pipe body 2 5 are the main structural parts of the floating collar and the floating shoe, and are made of high-strength materials such as carbon steel to ensure their durability and strength in harsh environments. The detachable connecting piece 1 3 and the detachable connecting piece 2 have the same structure and the same function, both of which are to improve the tightness and reliability of the connection with the casing 1, to prevent accidental separation between the casing and the floating collar and the floating shoe, and are beneficial to ensure the integrity of the entire system in a high-pressure or high-vibration environment. The one-way flow guiding piece 2 and the one-way flow guiding piece 1 4 have the same structure and similar functions. The one-way flow guiding piece 2 is located inside the floating shoe, and its main function is to help the casing smoothly enter the wellbore and prevent the fluid in the well from entering the inside of the casing, playing a role of the first layer of protection. The one-way flow guiding piece 1 4 is located inside the floating collar. Once the casing reaches the predetermined position and a cementing operation is carried out, the cement slurry will be pumped into the annular space between the casing and the wellbore wall to fix the casing. At this time, the function of the one-way flow guiding piece 1 4 is to prevent the cement slurry from flowing back into the casing 1, ensure that the cement slurry can be evenly distributed around the casing 1, and form an effective sealing layer. This not only helps to keep the casing 1 stable, but also prevents the collapse of the wellbore wall or other downhole problems from occurring, thus playing a role of the second layer of protection. The guiding cap 6 is integrally formed at the lower end of the pipe body 2 5, and its presence helps to reduce the resistance encountered when the casing 1 is lowered and helps the casing 1 to accurately enter the wellbore along the predetermined path;

[0042] The main structures of both the float collar and the float shoe in this application are the same, which means design consistency and simplification, facilitating large-scale production. At the same time, this consistency also makes it easier to maintain and replace. The same spare parts can be used to repair either the float collar or the float shoe. The two components of the anti-disconnection connector one 3 and the anti-disconnection connector two have the same structure, which means that the manufacturer can mass-produce these components in the factory, thereby reducing the manufacturing cost and improving the production efficiency. And because they are universal, there is no need to distinguish different connectors in actual applications, simplifying the installation process and reducing the risk caused by misusing different types of connectors. Although the one-way flow guide one 4 and the one-way flow guide two are located inside the float collar and the float shoe, their functions are similar, both to prevent fluid backflow and ensure the success of the cementing operation. By adopting the same structural design, these flow guides can provide a consistent sealing effect and increase the reliability of the system;

[0043] Specifically, the one-way flow guide one 4 includes a flow blocking plate one 41, a sealing ball one 42, a ball rod one 43, a spring one 44, and a flower basket 45. The flow blocking plate one 41 is arranged inside the pipe body one 2. The inside of the flow blocking plate one 41 is hollow and an opening one 411 is formed through the lower end. The flower basket 45 is fixedly installed at the central position inside the opening one 411. The ball rod one 43 is movably installed at the middle position of the flower basket 45. The sealing ball one 42 is fixedly installed at the top end of the ball rod one 43. The spring one 44 is sleeved outside the ball rod one 43. The upper end of the spring one 44 abuts against the sealing ball one 42 and the lower end abuts against the flower basket 45. An opening two 412 is formed through the central position at the upper end of the flow blocking plate one 41. A spherical sealing groove one 413 is formed at the lower end of the opening two 412. The spherical sealing groove one 413 corresponds to the sealing ball one 42;

[0044] The baffle plate 41 is one of the core components of the one-way flow guiding member. It is located inside the pipe body 2 and is designed to be hollow. There is an opening 411 at its lower end to allow the fluid to pass through. There is also an opening 412 at the central position of the upper end of the baffle plate 41 for the entry of the fluid. A spherical sealing groove 413 is provided below the opening 412 and is used in conjunction with the sealing ball 42 to achieve sealing. The flower basket 45 is fixedly installed at the central position inside the opening 411. It provides a fixed support point where the rod 43 can move. The design of the flower basket 45 helps to reduce the impact of the fluid on the rod 43 and the sealing ball 42, while ensuring their free movement. The rod 43 is a rod connecting the sealing ball 42 and the spring 44 and can move at the middle position of the flower basket 45. Its main function is to connect the sealing ball 42 and the spring 44, so as to ensure that the sealing ball 42 can move up and down when needed. When there is no fluid pressure or reverse flow occurs, the sealing ball 42 is located in the spherical sealing groove 413 to prevent the reverse flow of the fluid. When the forward fluid passes through, the pressure of the fluid will push the sealing ball 42 away from the spherical sealing groove 413, allowing the fluid to flow out through the opening 412 and the opening 411. The spring 44 is sleeved outside the rod 43 and provides a restoring force. When the forward fluid stops flowing or reverse flow occurs, the spring 44 helps the sealing ball 42 to quickly return to the position of the spherical sealing groove 413 to re-establish the sealing state and prevent reverse flow;

[0045] When the fluid flows from above (opening 412) to below (opening 411), the pressure of the fluid will overcome the elastic force of the spring 44 and push the sealing ball 42 away from the spherical sealing groove 413, allowing the fluid to pass through. Once the fluid attempts to flow in the reverse direction (i.e., from below to above), the sealing ball 42 will be pressed against the spherical sealing groove 413 under the action of the spring 44 to form a seal and prevent the occurrence of reverse flow;

[0046] Specifically, the one-way flow guiding member 4 further includes a baffle plate 46, a sealing ball 47, a spring 48 and a rod 49. The baffle plate 46 is fixedly installed inside the pipe body 2. The baffle plate 46 is arranged above the baffle plate 41. The rod 49 is movably installed through the upper edge position of the baffle plate 41. The rod 49 is arranged in a circumferential array at the upper end of the baffle plate 41. The sealing ball 47 is fixedly installed at the top of the rod 49. The spring 48 is sleeved outside the rod 49. The upper end of the spring 48 abuts against the sealing ball 47 and the lower end abuts against the baffle plate 41. An opening 461 is formed through the upper end of the baffle plate 46. The opening 461 is arranged in a circumferential array on the baffle plate 46. A spherical sealing groove 462 is formed at the lower end of the opening 461. The spherical sealing groove 462 and the sealing ball 47 are arranged in one-to-one correspondence;

[0047] The baffle plate two 46 is a new component fixedly installed inside the pipe body one 2, above the baffle plate one 41. It communicates with the outside through a plurality of openings three 461, and there is a spherical sealing groove two 462 below each opening three 461. The sealing ball two 47 is installed at the top of the ball rod two 49, corresponding to the spherical sealing groove two 462 one by one. Their function is to form a seal in the spherical sealing groove two 462 to prevent fluid backflow when there is no positive fluid pressure or reverse flow occurs. The spring two 48 is sleeved outside the ball rod two 49 to provide a restoring force. When the positive fluid passes through, the pressure of the fluid will compress the spring two 48, causing the sealing ball two 47 to leave the spherical sealing groove two 462. When there is reverse flow or no fluid flow, the spring two 48 will push the sealing ball two 47 back to the sealing position. The ball rod two 49 is movably installed through the upper edge position of the baffle plate one 41 and is distributed in a circumferential array. They connect the sealing ball two 47 and the spring two 48, allowing the sealing ball two 47 to move up and down according to the fluid pressure;

[0048] When the fluid enters through the opening three 461 and passes through the baffle plate two 46, the pressure of the fluid will overcome the elastic force of the spring two 48, pushing the sealing ball two 47 away from the spherical sealing groove two 462, and the fluid can flow out through the opening two 412 and the opening one 411 on the baffle plate two 46 and the baffle plate one 41. Once the fluid attempts to flow reversely (i.e., from bottom to top), the sealing ball two 47 will closely adhere to the spherical sealing groove two 462 under the action of the spring two 48 to form a seal and prevent reverse flow. At the same time, if the first-stage seal (composed of the sealing ball one 42 and the spherical sealing groove one 413) fails, the second-stage sealing system will serve as a backup to continue to prevent reverse flow. The double-sealing mechanism significantly enhances the safety and reliability of the system. Even under extreme conditions, such as high-pressure or high-vibration environments, the double protection can ensure that the fluid does not flow back into the casing, thus ensuring the successful completion of the cementing operation;

[0049] Specifically, the diameter of the opening one 411 is larger than the diameter of the opening two 412. The flower basket 45 includes a central fixing block 451 and a connecting rod 452. The central fixing block 451 is arranged at the central position of the opening one 411. The central fixing block 451 and the baffle plate one 41 are fixedly connected through the connecting rod 452. The connecting rod 452 is arranged in a circumferential array. The diameter of the opening two 412 is larger than the diameter of the opening three 461;

[0050] The first opening 411 is an opening located at the lower end of the first baffle 41, with a relatively large diameter, allowing the first sealing ball 42 to move freely under the action of the first spring 44 and ensuring sufficient flow through. The second opening 412 is an opening located at the central position of the upper end of the first baffle 41. Its diameter is smaller than that of the first opening 411 but larger than that of the third opening 461. Such a design can ensure that the fluid can smoothly enter and push the first sealing ball 42 away from the first spherical sealing groove 413. The third opening 461 is a plurality of openings located on the second baffle 46, arranged in a circumferential array, with the smallest diameter, which helps to control the flow path of the fluid and ensures that there is a corresponding second sealing ball 47 and second spherical sealing groove 462 below each opening to achieve effective sealing. The central fixing block 451 is the core part of the flower basket 45, fixedly installed at the central position of the first opening 411. Its function is to provide a stable support point for the first ball rod 43, ensuring that the first sealing ball 42 can move up and down at its central position. The connecting rod 452 connects the central fixing block 451 to the first baffle 41, distributed in a circumferential array, which not only enhances the overall structural strength of the flower basket 45 but also ensures that the fluid can be uniformly resisted when passing through the first opening 411, thus not affecting the normal operation of the first sealing ball 42, helping to disperse the fluid pressure and avoiding damage to the sealing ball or other components due to excessive local pressure;

[0051] Specifically, the first baffle 41 is movably installed in the first pipe body 2, and the outer wall surface of the first baffle 41 is in sliding contact with the inner wall surface of the first pipe body 2. A placement groove 414 is formed on the side wall of the first baffle 41. The placement groove 414 is arranged in a circumferential array around the first opening 411. A pushing member 7 is provided in the placement groove 414, which is used to push the first baffle 41 towards the second baffle 46 after being pressed, so as to improve the sealing performance of the third opening 461. A rubber sealing ring 415 is embedded and installed on the upper side wall of the first baffle 41;

[0052] The baffle plate 41 is designed to move only upward, which means that it can move in the direction of the baffle plate 46 under high pressure to enhance the sealing effect. Over time and under continuous pressure, the elasticity of the spring 48 will gradually weaken due to material fatigue, creep, or other factors. When the restoring force of the spring 48 is not sufficient to overcome the high pressure in the well, the spring 48 will not be able to effectively hold the baffle plate 41 in its original position. As the pressure in the well increases, if the restoring force of the spring 48 is not sufficient to offset this pressure, then the fluid pressure in the well will directly act on the baffle plate 41, forcing it to move upward. This process can automatically adjust the tightness of the seal to ensure good sealing performance even in a high-pressure environment. When the baffle plate 41 moves upward and approaches the baffle plate 46, it can fit more closely around the spherical sealing groove 462 around the opening 461, so that the sealing ball 47 can better fill these grooves to provide a better sealing effect. The rubber sealing ring 415 is embedded and installed on the upper side wall of the baffle plate 41 to provide an additional sealing layer. When the baffle plate 41 moves, the rubber sealing ring 415 can ensure the sealing performance between it and the inner wall of the pipe body 2 to avoid fluid leakage. The rubber material has good elasticity and wear resistance, which enables it to maintain a good sealing effect after long-term use;

[0053] Specifically, the pusher 7 includes a spring 71, a pusher block 72, a pusher head 73, and a rack 74. One end of the placement groove 414 adjacent to the opening 411 is fixedly installed with the spring 71. The telescopic end of the spring 71 is fixedly installed with the pusher block 72. The end of the pusher block 72 is fixedly installed with the pusher head 73. A sliding contact surface 731 is provided on the pusher head 73. A strip-shaped groove 21 is provided on the inner wall of the pipe body 2. The strip-shaped groove 21 and the placement groove 414 are arranged in one-to-one correspondence. The rack 74 is fixedly installed in the strip-shaped groove 21. A sliding contact surface 741 corresponding to the sliding contact surface 731 is provided on the rack 74. The sliding contact surface 741 and the sliding contact surface 731 are in sliding contact;

[0054] In the absence of external pressure, the spring three 71 is at its natural length. At this time, the pushing block 72 and the pushing head 73 are located at the starting position of the placement groove 414. The sliding contact surface one 731 of the pushing head 73 remains in contact with the sliding contact surface two 741 of the rack 74 but does not generate additional thrust. When the pressure in the well is too high or the elasticity of the spring two 48 weakens, this pressure acts on the pushing block 72 and the pushing head 73, causing them to overcome the elastic force of the spring three 71 and slide along the rack 74. Due to the design of the sliding contact surface one 731 and the sliding contact surface two 741, this sliding is smooth and controllable. As the pushing head 73 slides along the rack 74, it exerts an upward thrust on the choke plate one 41, causing the choke plate one 41 to gradually approach the choke plate two 46, thereby increasing the sealing performance of the opening three 461;

[0055] Specifically, the anti - detachment connecting piece one 3 includes a connecting pipe 31 and an external - thread connecting ring 32. The outer diameters of the connecting pipe 31, the pipe body one 2, the casing 1, and the pipe body two 5 are the same. The external - thread connecting rings 32 are symmetrically and fixedly installed at the upper and lower ends of the connecting pipe 31. The inner diameters of the connecting pipe 31, the external - thread connecting rings 32, the pipe body one 2, the casing 1, and the pipe body two 5 are the same. Inner - thread grooves 33 are respectively opened at the upper and lower ends of the pipe body one 2 and the casing 1 and the upper end of the pipe body two 5. The inner - thread grooves 33 and the external - thread connecting rings 32 are correspondingly arranged, and the external - thread connecting rings 32 are thread - connected into the corresponding inner - thread grooves 33;

[0056] The connecting pipe 31 is the main part of the anti - detachment connecting piece one 3 and is used to connect different pipe segments. The outer diameter of the connecting pipe 31 is the same as that of other components (such as the pipe body one 2, the casing 1, and the pipe body two 5), which ensures the appearance consistency of the entire system and the convenience of installation. The external - thread connecting rings 32 are symmetrically and fixedly installed at the upper and lower ends of the connecting pipe 31. They are the parts with external threads and are designed to cooperate with the corresponding inner - thread grooves 33 to achieve the threaded connection between the connecting piece and other components. The inner - thread grooves 33 are respectively opened at the upper and lower ends of the pipe body one 2 and the casing 1 and the upper end of the pipe body two 5. The positions of the inner - thread grooves 33 correspond to the external - thread connecting rings 32 and are dimensionally matched, so that the external - thread connecting rings 32 can be accurately screwed into and fastened in the corresponding inner - thread grooves 33;

[0057] Specifically, an anti - detachment positioning groove 311 is opened in the connecting pipe 31. The anti - detachment positioning grooves 311 are arranged in a circumferential array in the connecting pipe 31. A multi - point locking piece 8 is provided in the anti - detachment positioning groove 311 for the anti - detachment fixation of the float collar and the float shoe;

[0058] The anti-loosening positioning groove 311 is a groove formed inside the connecting pipe 31 and is distributed in a circumferential array. This design allows for multiple locking positions, improving the stability and reliability of locking, providing a fixed interface for the multi-point locking member 8, enabling the locking member to accurately embed and fix the float collar or float shoe. Through this design, it can effectively prevent the float collar or float shoe from loosening or falling off due to vibration, impact, or other external forces during downhole operations, maintaining a high level of safety in extreme environments and avoiding major accidents caused by equipment detachment;

[0059] Specifically, the multi-point locking member 8 includes a locking block 81, a fixing plate 82, a first rotating rod 83, a first bevel gear 84, a second rotating rod 85, a second bevel gear 86, and a handle 87. The locking blocks 81 are symmetrically and movably installed in the anti-loosening positioning groove 311. A locking head 811 is fixedly installed at one end of the locking block 81 away from each other. Locking grooves 88 are evenly distributed in a circle at the upper and lower ends of the first pipe body 2 and the casing 1 and at the upper end of the second pipe body 5. The locking grooves 88 and the locking heads 811 are correspondingly arranged. The locking head 811 penetrates through the connecting pipe 31 and is located in the corresponding locking groove 88. The fixing plates 82 are symmetrically and fixedly installed in the anti-loosening positioning groove 311. The distance between the fixing plates 82 is smaller than the distance between the locking blocks 81. The first rotating rod 83 is movably installed inside the fixing plates 82. A first bevel gear 84 is fixedly installed at one end of the first rotating rod 83 opposite to each other. The other end of the first rotating rod 83 is threadedly connected to the corresponding locking block 81. The second rotating rod 85 is movably installed outside the anti-loosening positioning groove 311. One end of the second rotating rod 85 extends into the anti-loosening positioning groove 311 and a second bevel gear 86 is fixedly installed thereon. The second bevel gears 86 are respectively meshed and connected with the corresponding first bevel gears 84. The other end of the second rotating rod 85 penetrates through the connecting pipe 31 and is provided with the handle 87;

[0060] The locking blocks 81 are symmetrically and movably installed in the anti - detachment positioning grooves 311 and can move within the grooves. One end of each of them is fixed with a locking head 811 for embedding into the corresponding locking groove 88 to achieve the locking function. The locking head 811 is a part extending from the locking block 81 and can penetrate through the connecting pipe 31 and enter the locking groove 88 to complete the locking. The fixing plate 82 is fixed in the anti - detachment positioning groove 311, and the distance between the fixing plates 82 is smaller than the distance between the locking blocks 81, providing an installation basis for the first rotating rod 83. The first rotating rod 83 is movably installed between the fixing plates 82 and is thread - connected to the locking blocks 81. When rotated, it pushes or pulls the locking blocks 81 through the threads to make them move. The first bevel gear 84 is fixed to the opposite end of the first rotating rod 83 and meshes with the second bevel gear 86 to transmit power and make the first rotating rod 83 rotate synchronously. The second rotating rod 85 is movably installed outside the anti - detachment positioning groove 311 and extends into it. One end is fixed with the second bevel gear 86, and the other end is provided with a handle 87. The whole system is driven to work by rotating the handle 87. The second bevel gear 86 meshes with the first bevel gear 84 to convert the rotational movement of the second rotating rod 85 into the rotational movement of the first rotating rod 83. The handle 87 serves as a manual operation interface and starts the entire locking mechanism by rotation. The locking grooves 88 are evenly distributed circumferentially on the upper and lower ends of the first pipe body 2, the sleeve 1, and the upper end of the second pipe body 5, corresponding to the locking heads 811. After the locking heads 811 penetrate through the connecting pipe 31, they are located in the corresponding locking grooves 88 to achieve locking. Marking lines are correspondingly arranged outside the locking grooves 88, mainly used to help the operator quickly and accurately align the positions of the locking heads 811 and the locking grooves 88, which is beneficial for all the locking heads 811 to correctly enter the locking grooves 88. With the help of the marking lines, the adjustment time can be significantly reduced during the on - site installation process, improving work efficiency. In this application, there are 12 locking grooves 88 and 3 multi - point locking parts 8. Having more locking grooves 88 than actually needed can provide redundancy. If a specific locking groove 88 or its corresponding locking head 811 fails, the system can still achieve locking through other available locking grooves 88, thus improving the reliability of the system. At the same time, during the actual installation process, there may be certain errors. The additional locking grooves 88 allow the operator to select the most suitable locking position according to the actual situation to ensure the best locking effect;

[0061] Specifically, the handle 87 includes a connecting handle 871 and a screwing plate 872. The other end of the second rotating rod 85 is movably connected to the connecting handle 871. The screwing plate 872 is fixedly installed at the end of the connecting handle 871. A limiting block 851 is fixedly installed on one side of the second rotating rod 85. A limiting groove corresponding to the limiting block 851 is formed in the connecting handle 871. The limiting block 851 is movably installed in the limiting groove. An embedding groove 312 is formed in the side wall of the connecting pipe 31. The embedding grooves 312 and the handles 87 are arranged in one-to-one correspondence. The screwing plate 872 is embedded in the corresponding embedding groove 312. The outer wall surface of the screwing plate 872 is flush with the outer wall surface of the connecting pipe 31. Arc-shaped grooves 313 are symmetrically formed in the embedding groove 312. Hand-picking grooves are symmetrically formed in the side wall of the screwing plate 872.

[0062] The design that the screwing plate 872 is flush with the outer wall surface of the connecting pipe 31 reduces the possibility of accidental collision of the screwing plate 872 by external objects, and reduces the risk of unintended unlocking of the system due to accidental touch. The design of the limiting block 851 and the limiting groove ensures a stable mechanical connection between the second rotating rod 85 and the connecting handle 871, avoiding possible loosening or dislocation problems during operation. The embedded design and the treatment that the screwing plate 872 is flush with the outer wall surface of the connecting pipe 31 not only improve the overall aesthetic appearance, but also increase the safety of using the handle 87.

[0063] Working principle:

[0064] S1, Installation preparation stage

[0065] Component assembly: First, connect the float collar, the casing and the float shoe in sequence from top to bottom. The float collar includes a first pipe body 2, an anti-disconnection connector one 3 and a one-way flow guiding part one 4. The float shoe includes a second pipe body 5, a guiding cap 6, an anti-disconnection connector two and a one-way flow guiding part two. Each part is firmly connected through an external thread connecting ring 32 and an internal thread groove 33.

[0066] Locking mechanism setting: Use a multi-point locking part 8 (including a locking block 81, a first rotating rod 83, etc.) to tightly fix the float collar and the float shoe to the casing to ensure that they will not loosen or fall off due to vibration or impact.

[0067] S2, Casing lowering stage

[0068] Casing lowering: The guiding cap 6 helps the casing 1 to be smoothly lowered into the wellbore along a predetermined path, reducing resistance and avoiding the casing 1 from inserting into the wellbore rock formation.

[0069] Preliminary sealing: During the lowering process of the casing 1, the one-way flow guiding part two is located in the float shoe, preventing the fluid in the well from entering the inside of the casing 1, playing a first layer of protection role.

[0070] S3, Cementing operation stage

[0071] Cement slurry injection: After reaching the predetermined position, the well cementing operation is started, and cement slurry is pumped into the annular space between the casing 1 and the wellbore wall to fix the casing 1.

[0072] Forward flow control: The one-way flow guiding member 4 and the second one-way flow guiding member allow the forward flow of the cement slurry. However, when reverse flow is attempted, the sealing ball 42 and the sealing ball 47 will tightly adhere to the corresponding spherical sealing groove 413 under the action of the spring to form a seal and prevent reverse flow.

[0073] Automatic adjustment: When the pressure in the well changes, the advancing member 7 can automatically adjust the position of the flow restrictor plate 41 according to the actual pressure conditions. This adaptive design can ensure effective prevention of reverse flow of the cement slurry even in a high-pressure environment, while ensuring the cleanliness inside the casing. Over time, the elasticity of the second spring 48 will gradually weaken. However, due to the inclusion of the adjustable flow restrictor plate 41 in the design, the system can self-repair to a certain extent and maintain the required sealing standard.

[0074] Redundant protection: The second-level sealing system (such as the flow restrictor plate 46, the sealing ball 47, etc.) serves as a backup to further enhance the safety of the system.

[0075] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0076] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A detachable floating collar and floating shoe, comprising a floating collar, a casing (1) and a floating shoe, characterized in that: The float collar, the casing (1) and the float shoe are arranged in sequence from top to bottom. The float collar includes a first pipe body (2), a first anti-disconnection connecting piece (3) and a first one-way flow guiding piece (4). The first one-way flow guiding piece (4) is arranged inside the first pipe body (2) and is used to prevent the cement slurry from flowing back into the casing (1). The first anti-disconnection connecting pieces (3) are respectively arranged at the upper and lower ends of the first pipe body (2) and are used for anti-disconnection connection with the casing (1). The float shoe includes a second pipe body (5), a guiding cap (6), a second anti-disconnection connecting piece and a second one-way flow guiding piece. The second one-way flow guiding piece has the same structure and similar function as the first one-way flow guiding piece (4), and is used to help the casing (1) smoothly enter the wellbore and prevent the fluid in the well from entering the inside of the casing (1). The second anti-disconnection connecting piece is arranged at the upper end of the float shoe, and the second anti-disconnection connecting piece has the same structure and function as the first anti-disconnection connecting piece (3). The guiding cap (6) is integrally formed at the lower end of the second pipe body (5); The first one-way flow guiding piece (4) includes a first flow blocking plate (41), a second flow blocking plate (46), a second sealing ball (47), a second spring (48) and a second ball rod (49). The second flow blocking plate (46) is fixedly installed inside the first pipe body (2), and the second flow blocking plate (46) is arranged above the first flow blocking plate (41). The second ball rod (49) is movably installed through the upper edge position of the first flow blocking plate (41), and the second ball rods (49) are arranged in a circumferential array at the upper end of the first flow blocking plate (41). The second sealing ball (47) is fixedly installed at the top of the second ball rod (49). The second spring (48) is sleeved outside the second ball rod (49), the upper end of the second spring (48) abuts against the second sealing ball (47), and the lower end abuts against the first flow blocking plate (41). An opening three (461) is formed through the upper end of the second flow blocking plate (46), and the opening three (461) is arranged in a circumferential array on the second flow blocking plate (46). A second spherical sealing groove (462) is formed at the lower end of the opening three (461), and the second spherical sealing groove (462) corresponds to the second sealing ball (47) one by one; The first flow blocking plate (41) is movably installed inside the first pipe body (2), and the outer wall surface of the first flow blocking plate (41) is in sliding contact with the inner wall surface of the first pipe body (2). A placement groove (414) is formed on the side wall of the first flow blocking plate (41), and a pushing member (7) is arranged in the placement groove (414) and is used to push the first flow blocking plate (41) towards the second flow blocking plate (46) after being pressed, so as to improve the sealing performance of the opening three (461). When the restoring force of the second spring (48) is not enough to overcome the high pressure in the well, the fluid pressure in the well will directly act on the first flow blocking plate (41) and force it to move upward.

2. The anti - shedding float collar and float shoe according to claim 1, characterized in that: The one-way flow guiding member one (4) further includes a flow blocking plate one (41), a sealing ball one (42), a ball rod one (43), a spring one (44), and a flower basket (45). The flow blocking plate one (41) is arranged inside the pipe body one (2). The inside of the flow blocking plate one (41) is hollow and an opening one (411) is formed through the lower end. The placement grooves (414) are arranged in a circumferential array around the opening one (411). A flower basket (45) is fixedly installed at the central position inside the opening one (411). A ball rod one (43) is movably installed at the middle position of the flower basket (45). A sealing ball one (42) is fixedly installed at the top end of the ball rod one (43). The spring one (44) is sleeved outside the ball rod one (43). The upper end of the spring one (44) abuts against the sealing ball one (42) and the lower end abuts against the flower basket (45). An opening two (412) is formed through the central position of the upper end of the flow blocking plate one (41). A spherical sealing groove one (413) is formed at the lower end of the opening two (412). The spherical sealing groove one (413) and the sealing ball one (42) are arranged correspondingly.

3. The anti-detachment float collar and float shoe according to claim 2, wherein: The diameter of the opening one (411) is larger than the diameter of the opening two (412). The flower basket (45) includes a central fixing block (451) and connecting rods (452). The central fixing block (451) is arranged at the central position of the opening one (411). The central fixing block (451) and the flow blocking plate one (41) are fixedly connected through the connecting rods (452). The connecting rods (452) are arranged in a circumferential array. The diameter of the opening two (412) is larger than the diameter of the opening three (461).

4. A kind of anti - shedding float collar and float shoe according to claim 1, characterized in that: A rubber sealing ring (415) is embedded and installed on the side wall of the upper end of the flow blocking plate one (41).

5. A detachable floating collar and floating shoe according to claim 2, characterized in that: The pushing member (7) includes a spring three (71), a pushing block (72), a pushing head (73), and a rack (74). A spring three (71) is fixedly installed at one end adjacent to the opening one (411) in the placement groove (414). The telescopic end of the spring three (71) is fixedly installed with the pushing block (72). The end of the pushing block (72) is fixedly installed with the pushing head (73). A sliding contact surface one (731) is formed on the pushing head (73). A strip-shaped groove (21) is formed on the inner wall of the pipe body one (2). The strip-shaped groove (21) and the placement groove (414) are arranged in one-to-one correspondence. A rack (74) is fixedly installed in the strip-shaped groove (21). A sliding contact surface two (741) corresponding to the sliding contact surface one (731) is formed on the rack (74). The sliding contact surface two (741) and the sliding contact surface one (731) are in sliding contact.

6. The anti-detachment float collar and float shoe according to claim 1, characterized in that: The anti-loosening connecting piece one (3) includes a connecting pipe (31) and an external thread connecting ring (32). The outer diameters of the connecting pipe (31), the first pipe body (2), the sleeve (1), and the second pipe body (5) are the same. The external thread connecting rings (32) are symmetrically and fixedly installed at the upper and lower ends of the connecting pipe (31). The inner diameters of the connecting pipe (31), the external thread connecting rings (32), the first pipe body (2), the sleeve (1), and the second pipe body (5) are the same. Inner thread grooves (33) are respectively formed at the upper and lower ends of the first pipe body (2) and the sleeve (1) and at the upper end of the second pipe body (5). The inner thread grooves (33) and the external thread connecting rings (32) are correspondingly arranged, and the external thread connecting rings (32) are threadedly connected in the corresponding inner thread grooves (33).

7. The anti - dropping float collar and float shoe according to claim 6, characterized in that: An anti-loosening positioning groove (311) is formed in the connecting pipe (31). The anti-loosening positioning grooves (311) are arranged in a circumferential array in the connecting pipe (31). A multi-point locking piece (8) is arranged in the anti-loosening positioning groove (311) for anti-loosening fixation of the float collar and the float shoe.

8. A detachable floating collar and floating shoe according to claim 7, characterized in that: The multi-point locking piece (8) includes a locking block (81), a fixing plate (82), a first rotating rod (83), a first bevel gear (84), a second rotating rod (85), a second bevel gear (86), and a handle (87). The locking blocks (81) are symmetrically and movably installed in the anti-loosening positioning groove (311). A locking head (811) is fixedly installed at one end of the locking block (81) away from each other. Locking grooves (88) are evenly distributed in a circumferential manner at the upper and lower ends of the first pipe body (2) and the sleeve (1) and at the upper end of the second pipe body (5). The locking grooves (88) and the locking heads (811) are correspondingly arranged. The locking heads (811) penetrate through the connecting pipe (31) and are located in the corresponding locking grooves (88). The fixing plates (82) are symmetrically and fixedly installed in the anti-loosening positioning groove (311). The distance between the fixing plates (82) is smaller than the distance between the locking blocks (81). The first rotating rod (83) is movably installed in the fixing plate (82). The first bevel gears (84) are fixedly installed at the opposite ends of the first rotating rod (83). The first rotating rod (83) is threadedly connected to the corresponding locking block (81) at the end away from each other. The second rotating rod (85) is movably installed outside the anti-loosening positioning groove (311). One end of the second rotating rod (85) extends into the anti-loosening positioning groove (311) and is fixedly installed with the second bevel gear (86). The second bevel gears (86) are respectively meshed and connected with the corresponding first bevel gears (84). The other end of the second rotating rod (85) penetrates through the connecting pipe (31) and is provided with the handle (87).

9. The anti - dropping float collar and float shoe according to claim 8, characterized in that: The handle (87) includes a connecting handle (871) and a screwing plate (872). The other end of the second rotating rod (85) is movably connected to the connecting handle (871), and the screwing plate (872) is fixedly installed at the end of the connecting handle (871). A limiting block (851) is fixedly installed on one side of the second rotating rod (85). A limiting groove corresponding to the limiting block (851) is formed in the connecting handle (871), and the limiting block (851) is movably installed in the limiting groove. An embedding groove (312) is formed in the side wall of the connecting pipe (31), and the embedding grooves (312) are arranged in one-to-one correspondence with the handles (87). The screwing plate (872) is embedded in the corresponding embedding groove (312), and the outer wall surface of the screwing plate (872) is flush with the outer wall surface of the connecting pipe (31). Arc-shaped grooves (313) are symmetrically formed in the embedding groove (312), and manual grooves are symmetrically formed in the side wall of the screwing plate (872).

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