A flexible composite high-pressure transmission pipe for oil drilling

Abstract

The present invention discloses a flexible composite high-pressure delivery pipe for oil drilling, comprising a delivery pipe body, a first joint and a second joint, wherein the first joint is fixed to one end of the delivery pipe body, and the second joint is fixed to the other end of the delivery pipe body, the first joint comprises a tapered socket, and the second joint comprises an inner tapered sleeve, and the two delivery pipe bodies are arranged in the inner tapered sleeve of the second joint through the tapered socket of the first joint and are locked and fixed by an external locking mechanism. The present invention has a better anti-loosening effect through the tapered structure and the thread locking cooperation, and adopts an external locking mechanism to offset the loosening trend, thereby ensuring the sealing of the high-pressure delivery pipe joint for long-term use.

Description

Technical Field

[0001] The invention relates to a delivery pipe, in particular to a flexible composite high-pressure delivery pipe for oil drilling, belonging to the technical field of pipelines. Background Art

[0002] Flexible composite high-pressure transmission pipe is a kind of pipe fitting for the petroleum and natural gas industry made of polymer composite materials with certain high strength, high pressure, corrosion resistance, scaling resistance, small friction coefficient, good thermal insulation, good flexibility and long service life. Flexible composite high-pressure transmission pipe can be bent and twisted in a ring according to different terrains, which is easy to lay and has a short engineering period. However, in the actual pipeline laying, it is inevitable that there will be pipe joints. The joints commonly used in the prior art mainly adopt a threaded structure or a quick-plug joint structure with a continuous conical structure. After the installation of these two joints, although the sealing performance can meet the requirements, after a period of use, these two structural joints will loosen, causing the sealing performance of the joints to deteriorate, resulting in leakage of oil and natural gas at the joints, which is easy to cause safety hazards. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a flexible composite high-pressure delivery pipe for oil drilling to solve the problem of joint loosening.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A flexible composite high-pressure delivery pipe used in an oil drill comprises a delivery pipe body, a first joint and a second joint. The first joint is fixed to one end of the delivery pipe body, and the second joint is fixed to the other end of the delivery pipe body. The first joint comprises a tapered socket, and the second joint comprises an inner tapered sleeve. The tapered socket of the first joint is arranged in the inner tapered sleeve of the second joint between the two delivery pipe bodies and is locked and fixed by an external locking mechanism.

[0006] Furthermore, one end of the conical socket is provided with an annular groove matching the end of the delivery pipe body, the end of the delivery pipe body is inserted into the annular groove of the conical socket and crimped and fixed, and a conical surface structure is provided on the outer side of the other end of the conical socket.

[0007] Furthermore, an annular groove matching the end of the conveying pipe body is opened at one end of the inner conical sleeve, the end of the conveying pipe body is inserted into the annular groove of the inner conical sleeve and crimped and fixed, and an inner conical hole structure matching the conical surface structure of the conical socket is provided on the inner wall of the other end of the inner conical sleeve.

[0008] Furthermore, the external locking mechanism includes a first external sleeve, a second external sleeve and an intermediate spacer ring. The first external sleeve includes a small sleeve, a transition ring plate and a large sleeve. Both the small sleeve and the large sleeve are circular tube structures and the inner diameter of the small sleeve is smaller than the inner diameter of the large sleeve. The inner diameter of the small sleeve matches the outer diameter of the conveying pipe body. The inner diameter of the large sleeve is larger than the maximum outer diameter of the tapered socket. One end of the small sleeve and one end of the large sleeve are fixedly connected by a transition ring plate. When installed, the small sleeve is sleeved on the outer side of the conveying pipe body, the large sleeve is sleeved on the outer side of the tapered socket and the inner wall of the large sleeve does not contact the outer side surface of the tapered socket, and the transition ring plate rests on the outer edge of the end surface of the tapered socket at one end connected to the conveying pipe body; the second external sleeve includes an external sleeve body and an end sealing plate. The sleeve body is a circular tube structure, the inner diameter of the outer sleeve body matches the outer diameter of the inner tapered sleeve, the end sealing plate is fixed to one end of the outer sleeve body close to the conveying pipe body, and a through hole matching the outer diameter of the conveying pipe body is opened in the center of the end sealing plate. When installing, the end sealing plate is sleeved on the outside of the conveying pipe body through the through hole, and the outer sleeve body is sleeved on the outside of the inner tapered sleeve; the middle spacer ring is a circular ring structure, the inner diameter of the middle spacer ring matches the outer diameter of the conveying pipe body, and the outer diameter of the middle spacer ring matches the inner diameter of the outer sleeve body. When installing, the middle spacer ring is sleeved on the outside of the conveying pipe body and the middle spacer ring is located between the end sealing plate and the inner tapered sleeve; an internal thread is provided on the inner wall of the large sleeve, and an external thread meshing with the internal thread of the large sleeve is provided on the outer side of the outer sleeve body.

[0009] Furthermore, the middle spacer ring includes a spacer ring body, a spacer ring cover plate and a plurality of ball bearings. A groove matching the spacer ring cover plate is opened on one side of the spacer ring body, and a number of hemispherical holes corresponding to the ball bearings are arranged in the groove. A plurality of ball bearings are arranged one by one in the hemispherical holes of the groove. A small through hole is opened on the spacer ring cover plate corresponding to each hemispherical hole position, and the diameter of the small through hole is smaller than the diameter of the ball bearing. The spacer ring cover plate is arranged in the groove of the spacer ring body and fixed, and one side of the ball bearing is partially exposed from the small through hole.

[0010] Furthermore, it also includes an anti-falling mechanism, which includes a threaded sleeve, a movable ring and several groups of locking mechanisms. The threaded sleeve is a circular tube structure. The inner diameter of the threaded sleeve matches the outer diameter of the small sleeve and an internal thread is arranged on the inner wall of the threaded sleeve. The outer side of the small sleeve is provided with an external thread that meshes with the internal thread of the threaded sleeve. The threaded sleeve is arranged on the outer side of the small sleeve and is threadedly connected to the small sleeve. An annular groove arranged along the circumferential direction is opened on the outer side of the threaded sleeve. The movable ring is embedded in the annular groove on the outer side of the threaded sleeve and can rotate freely in the annular groove along the circumference of the threaded sleeve. The locking mechanisms are respectively connected to the movable ring and the middle spacer ring, and several groups of locking mechanisms are distributed at equal intervals along the circumferential direction of the movable ring and the middle spacer ring.

[0011] Furthermore, the locking mechanism includes a buckle, a buckle bracket and a hook, the buckle bracket is fixed on the outer side of the movable ring and a plurality of buckle brackets are evenly spaced along the circumference of the movable ring, one end of the buckle is hinged on the buckle bracket, the hook is arranged along the radial direction of the middle spacer ring, one end of the buckle hook is fixed on the outer side of the middle spacer ring and a plurality of buckle hooks are evenly spaced along the circumference of the middle spacer ring, a slot for the buckle hook to pass through is opened on the outer sleeve body, the slot is arranged on the side of the outer sleeve body along the axial direction of the outer sleeve body, the hook is arranged in the slot and can slide back and forth in the slot along the axial direction of the outer sleeve body, a notch matching the buckle is opened on the side of the buckle away from the buckle, and the other end of the buckle is buckled in the notch of the hook when locking.

[0012] Furthermore, the buckle ring is a U-shaped structure, and both ends of the U-shaped structure of the buckle ring are horizontally bent toward both sides and hinged on the buckle ring bracket.

[0013] Furthermore, a torsion spring is provided at the hinge between the buckle and the buckle bracket, and the torsion spring provides elastic force for the buckle in the counterclockwise direction.

[0014] Compared with the prior art, the present invention has the following advantages and effects:

[0015] 1. The present invention adopts a structure of a tapered socket and an inner tapered sleeve, and cooperates with a thread structure for locking. Compared with the traditional thread + sealing ring structure, the structure has a better sealing effect, and the tapered socket and the inner tapered sleeve are tightly fitted by the expansion force provided by the thread structure. At the same time, the tapered socket and the inner tapered sleeve provide a reverse expansion force to the thread structure, making the thread structure less likely to loosen;

[0016] 2. After the conical socket and the inner conical sleeve are inserted and locked, the present invention designs a locking mechanism on the outside. The locking mechanism is coordinated through the structures of the buckle ring, the buckle hook and the middle spacer ring. When the inner conical sleeve tends to loosen outward, the inner conical sleeve will generate an outward thrust to push the middle spacer ring outward. The middle spacer ring generates an outward thrust, which is transmitted to the movable ring through the buckle ring. The movable ring transmits the outward thrust to the first outer sleeve via the threaded sleeve. The first outer sleeve generates a thrust to push the conical socket toward the inner conical sleeve, so that the conical sleeve also has a tendency to move outward. This tendency offsets the loosening tendency of the inner conical sleeve, thereby eliminating the loosening tendency of the joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of a flexible composite high-pressure transmission pipe used in an oil drill according to the present invention.

[0018] Figure 2 The present invention is a cross-sectional view of a first joint and a second joint of a flexible composite high-pressure transmission pipe used in an oil drill.

[0019] Figure 3 is a cross-sectional view of a first outer sleeve of the present invention.

[0020] Figure 4 is a cross-sectional view of the second outer sleeve of the present invention.

[0021] Figure 5 It is a cross-sectional view of the middle spacer ring of the present invention. DETAILED DESCRIPTION

[0022] In order to elaborate on the technical scheme adopted by the present invention to achieve the predetermined technical purpose, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only partial embodiments of the present invention, rather than all embodiments, and the technical means or technical features in the embodiments of the present invention can be replaced without paying creative work. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0023] like Figure 1 As shown, a petroleum drill of the present invention uses a flexible composite high-pressure delivery pipe, which includes a delivery pipe body 1, a first joint 2 and a second joint 3. The first joint 2 is fixed to one end of the delivery pipe body 1, and the second joint 3 is fixed to the other end of the delivery pipe body 1. When in use, the first joint 2 of one high-pressure delivery pipe is plugged and locked with the second joint 3 of another high-pressure delivery pipe to achieve the connection of the two high-pressure delivery pipes.

[0024] like Figure 2 As shown, the first joint 2 includes a tapered socket 4, the second joint 3 includes an inner tapered sleeve 5, and the two conveying pipe bodies 1 are arranged in the inner tapered sleeve 5 of the second joint 3 through the tapered socket 4 of the first joint 2 and are locked and fixed by an external locking mechanism.

[0025] Among them, one end of the conical socket 4 is provided with an annular groove matching the end of the conveying pipe body 1, the end of the conveying pipe body 1 is inserted into the annular groove of the conical socket 4 and crimped and fixed, and the outer side of the other end of the conical socket 4 is provided with a conical surface structure.

[0026] One end of the inner tapered sleeve 5 is provided with an annular groove matching the end of the delivery pipe body 1, the end of the delivery pipe body 1 is inserted into the annular groove of the inner tapered sleeve 5 and crimped and fixed, and the inner wall of the other end of the inner tapered sleeve 5 is provided with an inner tapered hole structure matching the conical surface structure of the tapered socket 4. The present invention adopts the structure of the tapered socket and the inner tapered sleeve, and is locked with the thread structure. Compared with the traditional thread + sealing ring structure, the structure has a better sealing effect, and the tapered socket and the inner tapered sleeve are tightly matched by the expansion force provided by the thread structure, and at the same time, the tapered socket and the inner tapered sleeve provide a reverse expansion force to the thread structure, making the thread structure less likely to loosen.

[0027] like Figure 2 As shown, the external locking mechanism includes a first external sleeve 6 , a second external sleeve 7 and a middle spacer ring 8 .

[0028] Among them, Figure 3 As shown, the first outer sleeve includes a small sleeve 9, a transition ring plate 10 and a large sleeve 11. The small sleeve 9 and the large sleeve 11 are both circular tube structures and the inner diameter of the small sleeve 9 is smaller than the inner diameter of the large sleeve 11. The inner diameter of the small sleeve 9 matches the outer diameter of the conveying pipe body 1, and the inner diameter of the large sleeve 11 is larger than the maximum outer diameter of the tapered socket 4. One end of the small sleeve 9 and one end of the large sleeve 11 are fixedly connected by the transition ring plate 10 to form a step-like structure. When installed, the small sleeve 9 is sleeved on the outside of the conveying pipe body 1, and the large sleeve 11 is sleeved on the outside of the tapered socket 4, and the inner wall of the large sleeve 11 does not contact the outer side of the tapered socket 4, and the transition ring plate 10 abuts against the outer edge of the end face of the tapered socket 4 at one end connected to the conveying pipe body 1.

[0029] like Figure 4 As shown, the second outer sleeve 7 includes an outer sleeve body 12 and an end sealing plate 13. The outer sleeve body 12 is a circular tube structure. The inner diameter of the outer sleeve body 12 matches the outer diameter of the inner tapered sleeve 5. The end sealing plate 13 is fixed to one end of the outer sleeve body 12 close to the conveying pipe body 1. A through hole matching the outer diameter of the conveying pipe body 1 is opened in the center of the end sealing plate 13. When installed, the end sealing plate 13 is sleeved on the outside of the conveying pipe body 1 through the through hole, and the outer sleeve body 12 is sleeved on the outside of the inner tapered sleeve 5.

[0030] like Figure 5 As shown, the middle spacer ring 8 is a circular ring structure, the inner diameter of the middle spacer ring 8 matches the outer diameter of the conveying pipe body 1, and the outer diameter of the middle spacer ring 8 matches the inner diameter of the outer sleeve body 12. When installed, the middle spacer ring 8 is sleeved on the outside of the conveying pipe body 1 and the middle spacer ring 8 is located between the end sealing plate 13 and the inner conical sleeve 5.

[0031] The inner wall of the large sleeve 11 is provided with an internal thread, and the outer side of the external sleeve body 12 is provided with an external thread that meshes with the internal thread of the large sleeve 11. During installation, the external sleeve body 12 is inserted into the large sleeve 11, and then the large sleeve 11 is rotated so that the external sleeve body 12 and the large sleeve 11 gradually approach each other under the action of the thread, and the inner tapered socket 4 is automatically aligned with the inner tapered sleeve 5 and gradually inserted into the inner tapered sleeve 5 until the tapered surface structure of the tapered socket 4 is completely fitted with the inner tapered hole structure of the inner tapered sleeve 5. At this time, the large sleeve 11 is continuously rotated until it cannot be rotated, so that the tapered surface structure of the tapered socket 4 and the inner tapered hole structure of the inner tapered sleeve 5 are completely tightly sealed.

[0032] like Figure 5As shown, the middle spacer ring 8 comprises a spacer ring body 14, a spacer ring cover plate 15 and a plurality of balls 16. A groove matching the spacer ring cover plate 15 is provided on one side of the spacer ring body 14. The groove is provided with hemispherical holes corresponding to the number of balls 16. The plurality of balls 16 are arranged in the hemispherical holes of the groove one by one. A small through hole is provided on the spacer ring cover plate 15 corresponding to each hemispherical hole. The diameter of the small through hole is smaller than the diameter of the ball 16. The spacer ring cover plate 15 is covered and fixed in the groove of the spacer ring body 14. One side of the ball 16 is partially exposed from the small through hole. In this way, rolling friction is achieved on the end surface of the middle spacer ring 8 in contact with the end sealing plate 13 through the balls 16, reducing the friction force of the contact surface between the middle spacer ring 8 and the end sealing plate 13, so that when the end sealing plate 13 rotates, the rotational torque will not be transmitted to the inner tapered sleeve 5 through the middle spacer ring 8.

[0033] The flexible composite high-pressure delivery pipe for oil drilling of the present invention also includes an anti-falling mechanism, such as Figure 2 As shown, the anti-falling mechanism includes a threaded sleeve 17, a movable ring 18 and several groups of locking mechanisms. The threaded sleeve 17 is a circular tube structure. The inner diameter of the threaded sleeve 17 matches the outer diameter of the small sleeve 9 and an internal thread is arranged on the inner wall of the threaded sleeve 17. The outer side of the small sleeve 9 is provided with an external thread meshing with the internal thread of the threaded sleeve 17. The threaded sleeve 17 is sleeved on the outer side of the small sleeve 9 and is threadedly connected to the small sleeve 9. The outer side of the threaded sleeve 17 is provided with an annular groove arranged along the circumferential direction. The movable ring 18 is embedded in the annular groove on the outer side of the threaded sleeve 17 and can rotate freely in the annular groove along the circumference of the threaded sleeve 17. The locking mechanisms are respectively connected to the movable ring 18 and the middle spacer ring 8, and several groups of locking mechanisms are evenly spaced along the circumferential direction of the movable ring 18 and the middle spacer ring 8.

[0034] The locking mechanism includes a buckle ring 19, a buckle ring bracket 20 and a hook 21. The buckle ring bracket 20 is fixed to the outer side of the movable ring 18 and multiple buckle ring brackets 20 are evenly spaced along the circumference of the movable ring 18. One end of the buckle ring 19 is hinged on the buckle ring bracket 20. The hook 21 is arranged along the radial direction of the middle spacer ring 8. One end of the hook 21 is fixed to the outer side of the middle spacer ring 8 and multiple hooks 21 are evenly spaced along the circumference of the middle spacer ring 8. A slot 22 for the hook 21 to pass through is opened on the outer sleeve body 12. The slot 22 is arranged on the side of the outer sleeve body 12 along the axial direction of the outer sleeve body 12. The hook 21 is arranged in the slot 22 and can slide back and forth in the slot 22 along the axial direction of the outer sleeve body 12, such as Figure 5 As shown, a notch 23 matching the buckle ring 19 is formed on one side of the buckle hook 21 away from the buckle ring 19 , and the other end of the buckle ring 19 is buckled in the notch 23 of the buckle hook 21 when locked.

[0035] like Figure 1As shown, the buckle 19 is a U-shaped structure, and the two ends of the U-shaped structure of the buckle 19 are horizontally bent to both sides and hinged on the buckle bracket 20. A torsion spring is provided at the hinge of the buckle 19 and the buckle bracket 20, and the torsion spring provides elastic force in the counterclockwise direction for the buckle 19. When in use, after the conical surface structure of the conical socket 4 and the inner conical hole structure of the inner conical sleeve 5 are completely tightly fixed, the movable ring 18 is rotated to make the position of the buckle 19 correspond to the position of the hook 21, and then the buckle 19 is rotated clockwise to the notch 23 of the hook 21, and the threaded sleeve 17 is rotated to move the movable ring 18 to the left, so that the buckle 19 is clamped in the notch 23 of the hook 21, until the threaded sleeve 17 cannot be rotated, and the buckle 19 is completely locked in the notch 23 of the hook 21.

[0036] The present invention adopts the structure of a tapered socket and an inner tapered sleeve, and cooperates with a threaded structure for locking. Compared with the traditional thread + sealing ring structure, this structure has a better sealing effect, and the tapered socket and the inner tapered sleeve are tightly fitted through the expansion force provided by the threaded structure. At the same time, the tapered socket and the inner tapered sleeve provide a reverse expansion force to the threaded structure, making the threaded structure less likely to loosen. The present invention designs a locking mechanism on the outside after the tapered socket and the inner tapered sleeve are inserted and locked. The locking mechanism is coordinated through the structures of the buckle ring, the buckle hook and the middle spacer ring. When the inner tapered sleeve tends to loosen outward, the inner tapered sleeve will generate an outward thrust to push the middle spacer ring outward. The middle spacer ring generates an outward thrust, which is transmitted to the movable ring through the buckle ring. The movable ring transmits the outward thrust to the first outer sleeve via the threaded sleeve. The first outer sleeve generates a thrust that pushes the tapered socket toward the inner tapered sleeve, so that the tapered sleeve also has a tendency to move outward. This tendency offsets the loosening tendency of the inner tapered sleeve, thereby eliminating the loosening tendency of the joint.

[0037] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A flexible composite high-pressure transmission pipe for oil drilling, characterized in that: It comprises a conveying pipe body, a first joint and a second joint, the first joint is fixed to one end of the conveying pipe body, and the second joint is fixed to the other end of the conveying pipe body, the first joint comprises a tapered socket, and the second joint comprises an inner tapered sleeve, the two conveying pipe bodies are arranged in the inner tapered sleeve of the second joint through the tapered socket of the first joint and are locked and fixed by an external locking mechanism; the external locking mechanism comprises a first external sleeve, a second external sleeve and an intermediate spacer ring, the first external sleeve comprises a small sleeve, a transition ring plate and a large sleeve, the small sleeve and the large sleeve are both circular tube structures and the inner diameter of the small sleeve is smaller than the outer diameter of the large sleeve, the inner diameter of the small sleeve matches the outer diameter of the conveying pipe body, the inner diameter of the large sleeve is larger than the maximum outer diameter of the tapered socket, one end of the small sleeve and one end of the large sleeve are fixedly connected by a transition ring plate, when installed, the small sleeve is sleeved on the outer side of the conveying pipe body, the large sleeve is sleeved on the outer side of the tapered socket and the inner wall of the large sleeve is aligned with the outer wall of the tapered socket The side surfaces do not contact, and the transition ring plate rests on the outer edge of the end surface of one end where the tapered socket is connected to the conveying pipe body; the second outer sleeve includes an outer sleeve body and an end sealing plate, the outer sleeve body is a circular tube structure, the inner diameter of the outer sleeve body matches the outer diameter of the inner tapered sleeve, the end sealing plate is fixed to one end of the outer sleeve body close to the conveying pipe body, a through hole matching the outer diameter of the conveying pipe body is opened in the center of the end sealing plate, when installing, the end sealing plate is sleeved on the outside of the conveying pipe body through the through hole, and the outer sleeve body is sleeved on the outside of the inner tapered sleeve; the middle spacer ring is a circular ring structure, the inner diameter of the middle spacer ring matches the outer diameter of the conveying pipe body, the outer diameter of the middle spacer ring matches the inner diameter of the outer sleeve body, when installing, the middle spacer ring is sleeved on the outside of the conveying pipe body and the middle spacer ring is located between the end sealing plate and the inner tapered sleeve; an internal thread is provided on the inner wall of the large sleeve, and an external thread meshing with the internal thread of the large sleeve is provided on the outer side of the outer sleeve body.

2. The flexible composite high-pressure transmission pipe for oil drilling according to claim 1 is characterized in that: One end of the conical socket is provided with an annular groove matching the end of the delivery pipe body. The end of the delivery pipe body is inserted into the annular groove of the conical socket and crimped and fixed. The outer side of the other end of the conical socket is provided with a conical surface structure.

3. The flexible composite high-pressure transmission pipe for oil drilling according to claim 2 is characterized in that: One end of the inner conical sleeve is provided with an annular groove matching the end of the conveying pipe body. The end of the conveying pipe body is inserted into the annular groove of the inner conical sleeve and crimped and fixed. The inner wall of the other end of the inner conical sleeve is provided with an inner conical hole structure matching the conical surface structure of the conical socket.

4. The flexible composite high-pressure transmission pipe for oil drilling according to claim 1 is characterized in that: The middle spacer ring comprises a spacer ring body, a spacer ring cover plate and a plurality of balls. A groove matching the spacer ring cover plate is opened on one side of the spacer ring body, and a number of hemispherical holes corresponding to the balls are arranged in the groove. A plurality of balls are arranged one by one in the hemispherical holes of the groove. A small through hole is opened on the spacer ring cover plate corresponding to each hemispherical hole position, and the diameter of the small through hole is smaller than the diameter of the ball. The spacer ring cover plate is arranged in the groove of the spacer ring body and fixed, and one side of the ball is partially exposed from the small through hole.

5. The flexible composite high-pressure transmission pipe for oil drilling according to claim 1 is characterized in that: The invention also includes an anti-falling mechanism, which includes a threaded sleeve, a movable ring and several groups of locking mechanisms. The threaded sleeve is a circular tube structure. The inner diameter of the threaded sleeve matches the outer diameter of the small sleeve and an internal thread is arranged on the inner wall of the threaded sleeve. The outer side of the small sleeve is provided with an external thread meshing with the internal thread of the threaded sleeve. The threaded sleeve is arranged on the outer side of the small sleeve and is threadedly connected to the small sleeve. An annular groove arranged along the circumferential direction is opened on the outer side of the threaded sleeve. The movable ring is embedded in the annular groove on the outer side of the threaded sleeve and can rotate freely in the annular groove along the circumference of the threaded sleeve. The locking mechanisms are respectively connected to the movable ring and the middle spacer ring, and several groups of locking mechanisms are distributed at equal intervals along the circumferential direction of the movable ring and the middle spacer ring.

6. The flexible composite high-pressure transmission pipe for oil drilling according to claim 5, characterized in that: The locking mechanism includes a buckle ring, a buckle ring bracket and a buckle hook. The buckle ring bracket is fixed on the outer side of the movable ring and multiple buckle ring brackets are evenly spaced along the circumference of the movable ring. One end of the buckle ring is hinged on the buckle ring bracket. The buckle hook is arranged along the radial direction of the middle spacer ring. One end of the buckle hook is fixed on the outer side of the middle spacer ring and multiple buckle hooks are evenly spaced along the circumference of the middle spacer ring. A slot hole for the buckle hook to pass through is opened on the outer sleeve body. The slot hole is arranged on the side of the outer sleeve body along the axial direction of the outer sleeve body. The hook is arranged in the slot hole and can slide back and forth in the slot hole along the axial direction of the outer sleeve body. A notch matching the buckle ring is opened on the side of the buckle ring away from the buckle ring. When locking, the other end of the buckle ring is buckled in the notch of the buckle hook.

7. The flexible composite high-pressure transmission pipe for oil drilling according to claim 6 is characterized in that: The buckle ring is a U-shaped structure, and both ends of the U-shaped structure of the buckle ring are horizontally bent toward both sides and hinged on the buckle ring bracket.

8. The flexible composite high-pressure transmission pipe for oil drilling according to claim 7 is characterized in that: A torsion spring is provided at the hinged joint between the buckle ring and the buckle ring bracket, and the torsion spring provides elastic force for the buckle ring in the counterclockwise direction.

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