Locking structure with three locking rings

Abstract

The invention discloses a locking structure with three locking rings, which is arranged on a central pipe and comprises a sealing mechanism arranged on the central pipe, used for setting and sealing the central pipe, a locking ring mechanism arranged on the central pipe, connected with the sealing mechanism and used for fixing the sealing mechanism, and a piston mechanism connected with the sealing mechanism and used for fixing the sealing mechanism. And the sealing mechanism is arranged on the central pipe and is used for driving the sealing mechanism to complete setting of the central pipe. According to the locking structure with the three locking rings, the first sealing assembly and the second sealing assembly are independently locked through the first locking ring and the third locking ring correspondingly, it is ensured that sealing on the two sides stably takes effect in the setting and pressure bearing process, and sealing failure caused by mutual interference is effectively avoided; the second lock ring not only can prevent the first lock ring and the third lock ring from retreating to enhance the locking stability, but also can serve as a standby lock ring to provide continuous locking force when one side or two sides of the first lock ring and the third lock ring fail, and the problem of linkage sealing caused by single-point failure is solved.

Description

Technical Field

[0001] This invention relates to the field of downhole testing and deep extraction tools for oil and gas, specifically a locking structure with three locking rings. Background Technology

[0002] With the booming development of offshore exploration, my country's offshore oil industry is moving towards increasingly deeper waters. However, this also brings with it increasingly harsh operating conditions. Against this backdrop, the market demand for locking structures that can provide stable and efficient seals is becoming increasingly urgent. A high-performance locking structure can not only effectively cope with the harsh environments of deep-sea high pressure, high temperature, and strong corrosion, but also ensure the safety, stability, and efficiency of the oil extraction process. It is of vital strategic significance for matching the development of offshore oil exploration, safeguarding the continued development of my country's offshore oil industry, helping to expand into broader deep-sea oil and gas resources, and becoming a key technological support for driving the industry to new heights.

[0003] In offshore oil extraction, locking structures play a crucial role. The main functions of locking structures are: first, fixing the tool's position, ensuring the tool remains stably in its predetermined downhole location, and maintaining the relative position of the tool with the wellbore or other equipment; second, transmitting loads and forces, bearing and transmitting axial forces, and distributing and evenly distributing loads; third, controlling tool movements and operations, enabling the tool to open and close, controlling its movement and deformation, and achieving sequential and coordinated operation; fourth, providing sealing and isolation, offering sealing support, and protecting other components and systems; and fifth, increasing tool safety and reliability, preventing accidental release or movement of the tool, and serving as a safety backup. Summary of the Invention

[0004] The purpose of this invention is to provide a locking structure with three locking rings to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a locking structure with three locking rings, disposed on a central tube, comprising:

[0006] A sealing mechanism is provided on the central tube and is used to seal the central tube.

[0007] A locking ring mechanism is provided on the central tube and is connected to the sealing mechanism to fix the sealing mechanism.

[0008] A piston mechanism, which is located on the central tube, is used to drive the sealing mechanism to complete the setting and sealing of the central tube;

[0009] The locking ring mechanism includes a first locking ring, a second locking ring, and a third locking ring. The first locking ring and the third locking ring are respectively connected to the sealing mechanism. The second locking ring is not only connected to the sealing mechanism but also connected to both the first locking ring and the third locking ring. When the first locking ring and the third locking ring fail, the second locking ring provides locking force.

[0010] Preferably, the sealing mechanism includes a first sealing component and a second sealing component, which are respectively disposed at both ends of the central tube.

[0011] Preferably, the first sealing component is connected to the first locking ring, and the first sealing component is locked by the first locking ring.

[0012] Preferably, the second sealing assembly is connected to the third locking ring, and the second sealing assembly is locked by the third locking ring.

[0013] Preferably, the piston mechanism includes a first piston and a second piston, the first piston and the second piston being respectively connected to the sealing mechanism.

[0014] Preferably, the first piston and the first locking ring are connected, and the first piston drives the first sealing assembly to set in place using the first locking ring.

[0015] Preferably, the second piston and the third locking ring are connected, and the second piston uses the third locking ring to drive the second sealing assembly to set.

[0016] Preferably, a piston sleeve is provided on the outside of the locking ring mechanism, which is used to protect the locking ring mechanism and block mud and sand.

[0017] Preferably, each of the locking ring mechanisms is provided with a one-way tooth structure, which can jump teeth to push when force is applied in the direction of the teeth, thereby achieving one-way locking and locking the sealing mechanism.

[0018] Preferably, the second locking ring is used to prevent the first locking ring and the third locking ring from retracting;

[0019] The second locking ring is a spare locking ring for the first locking ring and the third locking ring.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The locking structure of the three locking rings independently locks the first sealing component and the second sealing component through the first locking ring and the third locking ring respectively, ensuring that the seals on both sides are stable and effective during the setting and pressure bearing process, effectively avoiding sealing failure caused by mutual interference; the second locking ring can not only prevent the first locking ring and the third locking ring from retracting to enhance locking stability, but also serve as a backup locking ring to provide continuous locking force when one or both sides fail, completely solving the chain sealing problem caused by single-point failure and greatly improving structural safety; the one-way tooth structure of the locking ring mechanism can achieve reliable one-way locking and avoid the risk of reverse unlocking; combined with the protective function of the piston sleeve, it can effectively block the impact and jamming of mud and sand, significantly extending the service life of the locking ring; the overall design relies on the central tube support, which can adapt to complex downhole environments such as deep-sea high pressure and high temperature, ensuring long-term stable sealing function, reducing the number of maintenance and replacements, reducing operating costs, and providing strong support for the efficient and safe operation of offshore oil extraction. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] In the figure: 1. First sealing assembly; 2. First locking ring; 3. First piston; 4. Second piston; 5. Second locking ring; 6. Third locking ring; 7. Second sealing assembly. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1 The present invention provides a technical solution: a locking structure with three locking rings, which is disposed on a central tube, comprising:

[0025] A sealing mechanism, located on the central tube, is used to set and seal the central tube. The sealing mechanism includes a first sealing component 1 and a second sealing component 7. The first sealing component 1 performs the sealing function on the upper side, relying on the independent locking of the first locking ring 2 to maintain the sealing state and ensure stable effectiveness during setting and pressure bearing. The second sealing component 7 performs the sealing function on the lower side, relying on the independent locking of the third locking ring 6 to maintain the sealing state and ensure stable effectiveness during setting and pressure bearing. The first sealing component 1 and the second sealing component 7 are respectively located at both ends of the central tube. The first sealing component 1 is connected to the first locking ring 2 and is locked by the first locking ring 2. The second sealing component 7 is connected to the third locking ring 6 and is locked by the third locking ring 6.

[0026] The sealing mechanism is located on the central tube and consists of a first sealing component 1 and a second sealing component 7 located at both ends of the central tube. The first sealing component 1 is connected to and locked by the first locking ring 2 to achieve the sealing function on the upper side, and maintains a stable sealing state by relying on the independent locking of the first locking ring 2 during the setting and pressure bearing process. The second sealing component 7 is connected to and locked by the third locking ring 6 to achieve the sealing function on the lower side, and maintains a stable sealing state by relying on the independent locking of the third locking ring 6 during the setting and pressure bearing process.

[0027] A locking ring mechanism, located on the central tube, is connected to the sealing mechanism and used to fix the sealing mechanism. The locking ring mechanism includes a first locking ring 2, a second locking ring 5, and a third locking ring 6. The first locking ring 2 and the third locking ring 6 are respectively connected to the sealing mechanism. The second locking ring 5 is connected not only to the sealing mechanism but also to both the first locking ring 2 and the third locking ring 6. When the first locking ring 2 and the third locking ring 6 fail, the second locking ring 5 provides locking force. A piston sleeve is provided on the outside of the locking ring mechanism to protect it and block mud and sand. Each locking ring has a one-way tooth structure; when force is applied in the tooth direction, it can skip teeth and push, achieving one-way locking and locking the sealing mechanism. The second locking ring 5 prevents the first locking ring 2 and the third locking ring 6 from retracting; the second locking ring 5 is a spare locking ring for the first locking ring 2 and the third locking ring 6. The first locking ring 2 provides independent locking support for the first sealing assembly 1, ensuring its independent sealing function in complex environments. It receives the load transmitted by the first piston 3 and pushes the first sealing assembly 1 to set. The first locking ring 2 cooperates with the second locking ring 5 to prevent the first locking ring 2 from retracting. In the event of a failure of the first locking ring 2, the second locking ring 5 can serve as a backup. Enclosed by the piston sleeve, it avoids impact and jamming from mud and sand. The third locking ring 6 provides independent locking support for the second sealing assembly 7, ensuring its independent sealing performance in complex downhole environments. It receives the load transmitted by the second piston 4, pushing the second sealing assembly 7 to set. The second sealing assembly 7 cooperates with the second locking ring 5 to prevent itself from retracting, and in the event of its own failure, the second locking ring 5 can serve as a backup. Enclosed by the piston sleeve or outer sleeve, it avoids impact and jamming from mud and sand. The second locking ring 5 provides additional locking to the first locking ring 2 and the third locking ring 6, preventing retraction of the first locking ring 2 and the third locking ring 6. As a backup structure for the double-sided locking rings, when one side of the first locking ring 2 or the third locking ring 6 fails, it can be converted into a backup locking ring to continue providing locking force for the corresponding first sealing assembly 1 or second sealing assembly 7, preventing seal failure. Enclosed by the piston sleeve or outer sleeve, it is protected from damage by external factors.

[0028] The locking ring mechanism is located on the central tube and connected to the sealing mechanism to fix it. It includes a first locking ring 2, a second locking ring 5, and a third locking ring 6. All three have a one-way tooth structure; when force is applied in the direction of the teeth, they can skip teeth to achieve one-way locking. An outer piston sleeve or outer sleeve is provided to protect the locking ring mechanism and block mud and sand. The first locking ring 2 is connected to the sealing mechanism, providing independent locking support for the first sealing assembly 1. It receives the load transmitted by the first piston 3 and pushes the first sealing assembly 1 to set. Simultaneously, it cooperates with the second locking ring 5 to prevent itself from retracting. If it fails, it can be repositioned by... The second locking ring 5 serves as a backup; the third locking ring 6 is connected to the sealing mechanism, providing independent locking support for the second sealing assembly 7, receiving the load transmitted by the second piston 4 and pushing the second sealing assembly 7 to set, while cooperating with the second locking ring 5 to prevent itself from retracting, and can be used as a backup in case of its own failure; the second locking ring 5 is connected to the first locking ring 2, the third locking ring 6 and the sealing mechanism respectively, providing additional locking for both to prevent retraction, and also serving as a backup locking ring, providing locking force for the corresponding sealing assembly in case of failure of the first locking ring 2 or the third locking ring 6, thus avoiding seal failure.

[0029] A piston mechanism, located on the central tube, is used to drive the sealing mechanism to complete the setting of the central tube. The piston mechanism includes a first piston 3 and a second piston 4, which are respectively connected to the sealing mechanism. The first piston 3 is connected to a first locking ring 2, and the first piston 3 drives the first sealing assembly 1 to set using the first locking ring 2. The second piston 4 is connected to a third locking ring 6, and the second piston 4 drives the second sealing assembly 7 to set using the third locking ring 6. The first piston 3 moves under the hydraulic pressure of the central tube, transmitting driving force to the first locking ring 2, which in turn drives the second piston 4 to complete the setting. The second piston 4 moves under the hydraulic pressure of the central tube, transmitting driving force to the first locking ring 2, which in turn drives the first sealing assembly 1 to complete the setting.

[0030] Example 1: A sealing mechanism is installed on the central tube and is used to set and seal the central tube. The sealing mechanism includes a first sealing component 1 and a second sealing component 7. The first sealing component 1 performs the sealing function on the upper side and relies on the independent locking of the first locking ring 2 to maintain the sealing state, ensuring stable effectiveness during setting and pressure bearing. The second sealing component 7 performs the sealing function on the lower side and relies on the independent locking of the third locking ring 6 to maintain the sealing state, ensuring stable effectiveness during setting and pressure bearing. The first sealing component 1 and the second sealing component 7 are respectively located at both ends of the central tube. The first sealing component 1 is connected to the first locking ring 2 and is locked by the first locking ring 2. The second sealing component 7 is connected to the third locking ring 6 and is locked by the third locking ring 6.

[0031] A locking ring mechanism, located on the central tube, is connected to the sealing mechanism and used to fix the sealing mechanism. The locking ring mechanism includes a first locking ring 2, a second locking ring 5, and a third locking ring 6. The first locking ring 2 and the third locking ring 6 are respectively connected to the sealing mechanism. The second locking ring 5 is connected not only to the sealing mechanism but also to both the first locking ring 2 and the third locking ring 6. When the first locking ring 2 and the third locking ring 6 fail, the second locking ring 5 provides locking force. A piston sleeve is provided on the outside of the locking ring mechanism to protect it and block mud and sand. Each locking ring has a one-way tooth structure; when force is applied in the tooth direction, it can skip teeth and push, achieving one-way locking and locking the sealing mechanism. The second locking ring 5 prevents the first locking ring 2 and the third locking ring 6 from retracting; the second locking ring 5 is a spare locking ring for the first locking ring 2 and the third locking ring 6. The first locking ring 2 provides independent locking support for the first sealing assembly 1, ensuring its independent sealing function in complex environments. It receives the load transmitted by the first piston 3 and pushes the first sealing assembly 1 to set. The first locking ring 2 cooperates with the second locking ring 5 to prevent the first locking ring 2 from retracting. In the event of a failure of the first locking ring 2, the second locking ring 5 can serve as a backup. Enclosed by the piston sleeve, it avoids impact and jamming from mud and sand. The third locking ring 6 provides independent locking support for the second sealing assembly 7, ensuring its independent sealing performance in complex downhole environments. It receives the load transmitted by the second piston 4, pushing the second sealing assembly 7 to set. The second sealing assembly 7 cooperates with the second locking ring 5 to prevent itself from retracting, and in the event of its own failure, the second locking ring 5 can serve as a backup. Enclosed by the piston sleeve or outer sleeve, it avoids impact and jamming from mud and sand. The second locking ring 5 provides additional locking to the first locking ring 2 and the third locking ring 6, preventing retraction of the first locking ring 2 and the third locking ring 6. As a backup structure for the double-sided locking rings, when one side of the first locking ring 2 or the third locking ring 6 fails, it can be converted into a backup locking ring to continue providing locking force for the corresponding first sealing assembly 1 or second sealing assembly 7, preventing seal failure. Enclosed by the piston sleeve or outer sleeve, it is protected from damage by external factors.

[0032] A piston mechanism, located on the central tube, is used to drive the sealing mechanism to complete the setting of the central tube. The piston mechanism includes a first piston 3 and a second piston 4, which are respectively connected to the sealing mechanism. The first piston 3 is connected to a first locking ring 2, and the first piston 3 drives the first sealing assembly 1 to set using the first locking ring 2. The second piston 4 is connected to a third locking ring 6, and the second piston 4 drives the second sealing assembly 7 to set using the third locking ring 6. The first piston 3 moves under the hydraulic pressure of the central tube, transmitting driving force to the first locking ring 2, which in turn drives the second piston 4 to complete the setting. The second piston 4 moves under the hydraulic pressure of the central tube, transmitting driving force to the first locking ring 2, which in turn drives the first sealing assembly 1 to complete the setting.

[0033] The first piston 3 pushes the first locking ring 2, causing the first sealing assembly 1 to set. The second piston 4 pushes the third locking ring 6, causing the second sealing assembly 7 to set. During this process, the first locking ring 2, the second locking ring 5, and the third locking ring 6 all engage with the central tube through their own one-way tooth structure, adjusting their position by jumping teeth when subjected to force in the direction of the teeth. After the first sealing assembly 1 and the second sealing assembly 7 are set, the one-way teeth of the second locking ring 5 form a reverse engagement with the one-way teeth of the first locking ring 2 and the third locking ring 6: if the first locking ring 2 and the third locking ring 6 show a reverse retraction tendency due to downhole pressure, the one-way teeth of the second locking ring 5 will lock with the one-way teeth of the two, using the one-way locking characteristic to prevent their retraction. At the same time, the one-way teeth of the second locking ring 5 engage with the one-way teeth of the central tube, further enhancing the overall locking stability. In addition, the piston sleeve on the outside of the locking ring mechanism wraps around the first locking ring 2, the second locking ring 5, and the third locking ring 6 to avoid interference from mud and sand, ensuring precise inter-tooth engagement among the three and continuously maintaining the locked state.

[0034] Example 2: A sealing mechanism is installed on the central tube and is used to set and seal the central tube. The sealing mechanism includes a first sealing component 1 and a second sealing component 7. The first sealing component 1 performs the sealing function on the upper side and relies on the independent locking of the first locking ring 2 to maintain the sealing state, ensuring stable effectiveness during setting and pressure bearing. The second sealing component 7 performs the sealing function on the lower side and relies on the independent locking of the third locking ring 6 to maintain the sealing state, ensuring stable effectiveness during setting and pressure bearing. The first sealing component 1 and the second sealing component 7 are respectively located at both ends of the central tube. The first sealing component 1 is connected to the first locking ring 2 and is locked by the first locking ring 2. The second sealing component 7 is connected to the third locking ring 6 and is locked by the third locking ring 6.

[0035] A locking ring mechanism, located on the central tube, is connected to the sealing mechanism and used to fix the sealing mechanism. The locking ring mechanism includes a first locking ring 2, a second locking ring 5, and a third locking ring 6. The first locking ring 2 and the third locking ring 6 are respectively connected to the sealing mechanism. The second locking ring 5 is connected not only to the sealing mechanism but also to both the first locking ring 2 and the third locking ring 6. When the first locking ring 2 and the third locking ring 6 fail, the second locking ring 5 provides locking force. A piston sleeve is provided on the outside of the locking ring mechanism to protect it and block mud and sand. Each locking ring has a one-way tooth structure; when force is applied in the tooth direction, it can skip teeth and push, achieving one-way locking and locking the sealing mechanism. The second locking ring 5 prevents the first locking ring 2 and the third locking ring 6 from retracting; the second locking ring 5 is a spare locking ring for the first locking ring 2 and the third locking ring 6. The first locking ring 2 provides independent locking support for the first sealing assembly 1, ensuring its independent sealing function in complex environments. It receives the load transmitted by the first piston 3 and pushes the first sealing assembly 1 to set. The first locking ring 2 cooperates with the second locking ring 5 to prevent the first locking ring 2 from retracting. In the event of a failure of the first locking ring 2, the second locking ring 5 can serve as a backup. Enclosed by the piston sleeve, it avoids impact and jamming from mud and sand. The third locking ring 6 provides independent locking support for the second sealing assembly 7, ensuring its independent sealing performance in complex downhole environments. It receives the load transmitted by the second piston 4, pushing the second sealing assembly 7 to set. The second sealing assembly 7 cooperates with the second locking ring 5 to prevent itself from retracting, and in the event of its own failure, the second locking ring 5 can serve as a backup. Enclosed by the piston sleeve or outer sleeve, it avoids impact and jamming from mud and sand. The second locking ring 5 provides additional locking to the first locking ring 2 and the third locking ring 6, preventing retraction of the first locking ring 2 and the third locking ring 6. As a backup structure for the double-sided locking rings, when one side of the first locking ring 2 or the third locking ring 6 fails, it can be converted into a backup locking ring to continue providing locking force for the corresponding first sealing assembly 1 or second sealing assembly 7, preventing seal failure. Enclosed by the piston sleeve or outer sleeve, it is protected from damage by external factors.

[0036] A piston mechanism, located on the central tube, is used to drive the sealing mechanism to complete the setting of the central tube. The piston mechanism includes a first piston 3 and a second piston 4, which are respectively connected to the sealing mechanism. The first piston 3 is connected to a first locking ring 2, and the first piston 3 drives the first sealing assembly 1 to set using the first locking ring 2. The second piston 4 is connected to a third locking ring 6, and the second piston 4 drives the second sealing assembly 7 to set using the third locking ring 6. The first piston 3 moves under the hydraulic pressure of the central tube, transmitting driving force to the first locking ring 2, which in turn drives the second piston 4 to complete the setting. The second piston 4 moves under the hydraulic pressure of the central tube, transmitting driving force to the first locking ring 2, which in turn drives the first sealing assembly 1 to complete the setting.

[0037] The first locking ring 2 fails due to mud and sand blockage or wear of the one-way teeth, and can no longer provide locking force to the first sealing assembly 1. At this time, the second locking ring 5 is activated as a backup locking ring: its one-way teeth on the side closest to the first locking ring 2 engage with the force-bearing end of the first sealing assembly 1, while the second locking ring 5 maintains a reverse locking with the one-way teeth of the central tube. When the first sealing assembly 1 shows a tendency to loosen due to the failure of the first locking ring 2, the second locking ring 5 is pushed in the direction of the teeth by the reaction force of the first sealing assembly 1, jumps to the corresponding locking position, and then clamps the central tube in reverse through the one-way teeth, providing continuous locking force to the first sealing assembly 1 and maintaining the upper sealing function.

[0038] Similarly, if the third locking ring 6 is damaged, the one-way teeth on the side of the second locking ring 5 closest to the third locking ring 6 will engage with the second sealing assembly 7, providing alternative locking force through one-way locking with the central tube, thus preventing the lower seal from failing. During this process, the piston sleeve's protection of the second locking ring 5 ensures it is not affected by external environmental interference, and the one-way tooth structure functions stably, guaranteeing the continuous effectiveness of the sealing assembly.

[0039] When the three-locking ring locking structure is in use, the pressure applied to the central tube generates hydraulic driving force, which drives the first piston 3 and the second piston 4 in the piston mechanism. The first piston 3 transmits the driving force to the first locking ring 2, pushing it to drive the first sealing assembly 1 to complete the setting. The second piston 4 transmits the driving force to the third locking ring 6, pushing it to drive the second sealing assembly 7 to complete the setting. During the setting process, the first locking ring 2, the second locking ring 5, and the third locking ring 6 of the locking ring mechanism all engage with the central tube through their own one-way tooth structure. When force is applied in the direction of the teeth, the teeth jump to adjust their position. After the first sealing assembly 1 and the second sealing assembly 7 are set, the first locking ring 2 independently locks the first sealing assembly 1 to maintain the upper sealing, and the third locking ring 6 independently locks the second sealing assembly 7 to maintain the lower sealing. At the same time, the one-way teeth of the second locking ring 5 form a reverse meshing with the one-way teeth of the first locking ring 2 and the third locking ring 6, using the one-way locking characteristic to prevent them from being released due to downhole pressure. The second locking ring 5, with its one-way teeth engaging with the central tube, further enhances the overall locking stability. When the first locking ring 2 fails due to mud or sand jamming or wear of the one-way teeth, the one-way teeth on the side of the second locking ring 5 closest to the first locking ring 2 engage with the force-bearing end of the first sealing assembly 1. Driven by the reaction force in the direction of the teeth, the teeth jump to the corresponding position and then, through the one-way teeth, clamp the central tube in the reverse direction, providing continuous locking force to the first sealing assembly 1 to maintain the upper seal. Similarly, if the third locking ring 6 fails, the one-way teeth on the side of the second locking ring 5 closest to the third locking ring 6 will engage with the second sealing assembly 7, providing alternative locking force through one-way locking with the central tube to prevent the lower seal from failing. Furthermore, the piston sleeve on the outside of the locking ring mechanism wraps around the first locking ring 2, the second locking ring 5, and the third locking ring 6, effectively blocking mud and sand impacts and jamming, ensuring precise engagement of the one-way teeth of each locking ring, guaranteeing stable operation of the entire structure in complex downhole environments, and achieving long-term effective setting and sealing of the central tube.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A locking structure with three locking rings, disposed on a central tube, characterized in that, include: A sealing mechanism is provided on the central tube and is used to seal the central tube. A locking ring mechanism is provided on the central tube and is connected to the sealing mechanism to fix the sealing mechanism. A piston mechanism, which is located on the central tube, is used to drive the sealing mechanism to complete the setting and sealing of the central tube; The locking ring mechanism includes a first locking ring (2), a second locking ring (5), and a third locking ring (6). The first locking ring (2) and the third locking ring (6) are respectively connected to the sealing mechanism. The second locking ring (5) is not only connected to the sealing mechanism but also connected to the first locking ring (2) and the third locking ring (6). When the first locking ring (2) and the third locking ring (6) fail, the second locking ring (5) provides locking force.

2. The locking structure with three locking rings according to claim 1, characterized in that: The sealing mechanism includes a first sealing component (1) and a second sealing component (7), which are respectively located at both ends of the central tube.

3. The locking structure with three locking rings according to claim 2, characterized in that: The first sealing component (1) is connected to the first locking ring (2), and the first sealing component (1) is locked by the first locking ring (2).

4. A locking structure with three locking rings according to claim 2 or 3, characterized in that: The second sealing assembly (7) is connected to the third locking ring (6), and the second sealing assembly (7) is locked by the third locking ring (6).

5. The locking structure with three locking rings according to claim 2, characterized in that: The piston mechanism includes a first piston (3) and a second piston (4), which are respectively connected to the sealing mechanism.

6. The locking structure with three locking rings according to claim 5, characterized in that: The first piston (3) is connected to the first locking ring (2), and the first piston (3) drives the first sealing assembly (1) to set and seal using the first locking ring (2).

7. A locking structure with three locking rings according to claim 5 or 6, characterized in that: The second piston (4) is connected to the third locking ring (6), and the second piston (4) drives the second sealing assembly (7) to set and seal using the third locking ring (6).

8. The locking structure with three locking rings according to claim 1, characterized in that: A piston sleeve is provided on the outside of the locking ring mechanism. The piston sleeve is used to protect the locking ring mechanism and block mud and sand.

9. The locking structure with three locking rings according to claim 1, characterized in that: Each locking ring mechanism is equipped with a one-way tooth structure. When force is applied in the direction of the teeth, the teeth can jump and push to achieve one-way locking and lock the sealing mechanism.

10. The locking structure with three locking rings according to claim 1, characterized in that: The second locking ring (5) is used to prevent the first locking ring (2) and the third locking ring (6) from retracting; The second locking ring (5) is a spare locking ring for the first locking ring (2) and the third locking ring (6).

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