Anti-rotation structure for overflowing pipe of intelligent layered water injection water distributor

Abstract

The utility model provides an anti-rotation structure for an overflowing pipe of an intelligent layered water injection water distributor. The anti-rotation structure comprises the overflowing pipe, a lower connector, an upper connector, a pull ring and an outer protective cylinder. Two arc-shaped plates are arranged at each of the two ends of the overflowing pipe, and mounting lugs are arranged on the outer wall of one side close to the end head; a first thread is arranged on the outer side wall of one end, close to the overflowing pipe, of the lower joint; an annular groove is formed in the outer side wall of the end, close to the overflowing pipe, of the upper connector. A second thread is arranged on the outer side wall of one end, close to the overflowing pipe, of the pull ring, and a plurality of center passing holes are uniformly formed in the outer side wall of the other end of the pull ring at intervals in the circumferential direction; the two ends of the outer protective cylinder are connected with the lower connector and the upper connector respectively and provided with a third thread and a pre-tightening thread respectively. An operator can screw the pull ring and the outer protective cylinder gradually by means of the center passing holes formed in the pull ring, and the upper connector is tightened under the pressure action of the pull ring, so that the friction force of the contact surface of the inner wall of the arc-shaped groove and the arc-shaped plate is increased, and the anti-rotation effect is achieved.

Description

Technical Field

[0001] The utility model relates to the field of underground stratified water injection, and in particular to an anti-rotation structure of a flow pipe of an intelligent stratified water injection water distributor. Background Art

[0002] Stratified water injection refers to a water injection method in which a packer is placed in the injection well to separate oil layers with large differences, and then water is distributed in layers using a water distributor, so that the water injection volume of the high permeability layer is controlled, the water injection of the medium and low permeability oil layers is strengthened, and all types of oil layers can play a role.

[0003] At present, the common anti-rotation structure of the flow pipe of the underground stratified water injection distributor is: the two ends of the hollow flow pipe are processed with squares, one end of the eccentric hole between the upper joint and the lower joint is processed with a square guide hole, and the end face of the upper joint and the lower joint has a threaded hole. The upper and lower pressure blocks are contacted with the outer wall of the flow pipe and screws are passed through the holes of the pressure blocks to form a bolt connection between the upper joint, the lower joint and the pressure block, which generates sliding friction and realizes the anti-rotation function of the flow pipe. This structure has many processing surfaces on the upper joint, the lower joint and the flow pipe, and the processing technology is complicated. It is difficult to achieve the matching tolerance of the square shaft hole, which makes the installation and disassembly process very inconvenient, and it is easy to rework, affecting the construction progress and generating additional costs. Utility Model Content

[0004] The main purpose of the utility model is to provide an anti-rotation structure for a flow pipe of an intelligent layered water injection and water distributor, so as to at least solve the problems that the processing technology of the existing anti-rotation structure is complicated and the disassembly process is very inconvenient.

[0005] In order to achieve the above-mentioned purpose, the utility model provides an anti-rotation structure of a flow pipe of an intelligent stratified water injection distributor, comprising: a flow pipe, the flow pipe is a cylindrical structure with a central cavity, two arc-shaped plates are arranged at each end of the flow pipe, and a mounting ear is arranged on the outer wall of one side of the flow pipe close to the end head; a lower joint, the lower joint is a cylindrical structure with a central cavity, the lower joint is connected to one end of the flow pipe, and a first thread is arranged on the outer wall of the end of the lower joint close to the flow pipe; an upper joint, the upper joint is a cylindrical structure with a central cavity, the upper joint is connected to the other end of the flow pipe, and a mounting ear is arranged on the outer wall of the end of the upper joint close to the flow pipe There is an annular groove; a pull ring, which is rotatably mounted on the annular groove, a second thread is provided on the outer wall of one end of the pull ring close to the flow tube, and a plurality of through-holes are evenly spaced circumferentially on the outer wall of the other end of the pull ring; an outer casing, which is a cylindrical structure with a central cavity, and is mounted on the flow tube, with the two ends of the outer casing respectively connected to the lower joint and the upper joint, and a third thread and a pre-tightening thread are respectively provided on the inner walls of the two ends of the outer casing; wherein the first thread and the third thread match and are screwed to each other, the second thread matches and is screwed to each other, and the mounting ear is connected to the end face of the lower joint.

[0006] Furthermore, the mounting ear is arranged at the rear end of the arc-shaped plate near one end of the lower joint, a countersunk hole is opened at the center position of the end surface of the mounting ear away from the lower joint, and a through hole penetrating the mounting ear is opened at the bottom of the countersunk hole; the flow tube also includes: two groups of double-circle annular sealing grooves, the two groups of double-circle annular sealing grooves are respectively opened on the outer side walls of the tail ends of the arc-shaped plate at both ends of the flow tube, and a sealing ring is installed in each double-circle annular sealing groove.

[0007] Furthermore, an arc-shaped groove matching the arc-shaped plate is provided on the inner side wall of one end of the lower joint and the upper joint connected to the flow pipe, and the arc-shaped plate is inserted into the arc-shaped groove.

[0008] Furthermore, a threaded hole corresponding to the through hole of the mounting ear is provided on the end surface of the lower joint contacting the flow tube, and the lower joint also includes: a first double-circle sealing groove, the first double-circle sealing groove is provided on the outer diameter close to one end of the flow tube, and contacts the side of the first thread away from the end head; wherein the mounting ear can be threadedly connected to the threaded hole by a screw passing through the through hole.

[0009] Furthermore, the upper joint further comprises: a second double-circle sealing groove, which is provided on the outer side wall close to one end of the flow tube and contacts with a side of the annular groove away from the end head.

[0010] Furthermore, the pull ring is divided into an upper pull ring and a lower pull ring, the upper pull ring and the lower pull ring are staggered and connected to each other through two positioning screws, and the upper pull ring and the lower pull ring are buckled and installed on the annular groove.

[0011] Furthermore, the outer casing is provided with a first annular groove and a second annular groove, the first annular groove is provided on the inner side wall of the end close to the lower joint, and the first annular groove corresponds to the position of the first double-circle sealing groove; the second annular groove is provided on the inner side wall of the end close to the upper joint, and the second annular groove corresponds to the position of the second double-circle sealing groove; wherein the third thread is provided on the inner side wall of the outer casing and contacts with the side of the first annular groove away from the end head; the pre-tightening thread is provided on the inner diameter of the outer casing and contacts with the side of the second annular groove away from the end head.

[0012] The utility model discloses an anti-rotation structure of a flow pipe of an intelligent stratified water injection distributor, comprising: a flow pipe, which is a cylindrical structure with a central cavity, two arc-shaped plates are arranged at each end of the flow pipe, and a mounting ear is arranged on an outer wall of one side of the flow pipe close to the end head; a lower joint, which is a cylindrical structure with a central cavity, connected to one end of the flow pipe, and a first thread is arranged on the outer wall of the end of the lower joint close to the flow pipe; an upper joint, which is a cylindrical structure with a central cavity, connected to the other end of the flow pipe, and an annular groove is arranged on the outer wall of the end of the upper joint close to the flow pipe; a pull ring The pull ring is rotatably sleeved on the annular groove, and a second thread is provided on the outer wall of one end of the pull ring close to the flow tube, and a plurality of through-holes are evenly spaced along the circumferential direction on the outer wall of the other end of the pull ring; an outer casing, the outer casing is a cylindrical structure with a central cavity, the outer casing is sleeved on the flow tube, the two ends of the outer casing are respectively connected to the lower joint and the upper joint, and a third thread and a pre-tightening thread are respectively provided on the inner side walls of the two ends of the outer casing; wherein the first thread and the third thread match and are screwed to each other, the second thread and the pre-tightening thread match and are screwed to each other, and the mounting ear is connected to the end face of the lower joint; the arc plate plugs at both ends of the flow tube The screws are inserted into the corresponding arc grooves on the inner side walls of the lower joint and the upper joint to form a preliminary limit, the mounting ear is aligned with the threaded hole of the lower joint, and the screws are passed through the through holes on the mounting ear and screwed into the threaded holes to fix the end faces of the mounting ear and the lower joint, thereby reinforcing the connection between the flow tube as a whole and the lower joint and preventing the flow tube from deflecting slightly; the crescent wrench can rotate the pull ring on the annular groove of the upper joint with the help of multiple through holes on the pull ring, so that the second thread on the pull ring and the pre-tightening thread on the outer casing are gradually tightened, the pull ring is tightened inwardly under external pressure, and the upper joint makes the flow tube The arc plate and the bottom end of the arc groove of the upper joint form an extrusion force to increase friction and play an anti-rotation role. During the specific assembly, the arc plate of the flow tube is first inserted into the arc groove of the lower joint, and then the mounting ears are fixed with screws, and then the outer casing is assembled; after the upper half pull ring and the lower half pull ring are assembled into the annular groove of the upper joint, the combination of the pull ring and the upper joint is combined with the spliced ​​outer casing and the lower joint to complete the assembly; this anti-rotation structure is simple and effective, and only needs to process the corresponding threads on the corresponding parts. It is also very convenient to assemble and can be mass-produced, which solves the problems of complex processing technology and inconvenient disassembly during construction in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings constituting part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0014] Figure 1 It is a structural schematic diagram of an anti-rotation structure of a flow pipe of an intelligent stratified water injection and water distributor that can be selected according to an embodiment of the utility model;

[0015] Figure 2 It is a structural schematic diagram of a flow pipe of a flow pipe anti-rotation structure of a smart stratified water injection and water distributor which can be selected according to an embodiment of the utility model;

[0016] Figure 3 It is a structural schematic diagram of a pull ring of a flow pipe anti-rotation structure of an intelligent stratified water injection and water distributor that can be selected according to an embodiment of the utility model;

[0017] Figure 4 It is a cross-sectional view of a pull ring of a flow pipe anti-rotation structure of an intelligent stratified water injection and water distributor which can be selected according to an embodiment of the utility model;

[0018] Figure 5 It is a structural schematic diagram of a lower joint of a flow pipe anti-rotation structure of an intelligent stratified water injection and water distributor which can be selected according to an embodiment of the utility model;

[0019] Figure 6 It is a structural schematic diagram of an upper joint of a flow pipe anti-rotation structure of an intelligent stratified water injection and water distributor that can be selected according to an embodiment of the utility model;

[0020] Figure 7 It is an exploded view of an anti-rotation structure of a flow pipe of an intelligent stratified water injection and water distributor that can be selected according to an embodiment of the utility model.

[0021] The above drawings include the following reference numerals:

[0022] 10. Flow tube; 11. Arc plate; 12. Mounting ear; 20. Lower joint; 21. First thread; 30. Upper joint; 31. Annular groove; 40. Pull ring; 41. Second thread; 42. Through hole; 50. Outer casing; 51. Third thread; 52. Pre-tightening thread; 121. Through hole; 13. Double-circle annular sealing groove; 14. Arc groove; 22. Threaded hole; 23. First double-circle sealing groove; 32. Second double-circle sealing groove; 43. Upper half pull ring; 44. Lower half pull ring; 54. First annular groove; 55. Second annular groove. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present utility model will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] In order to achieve the above-mentioned object, according to the first embodiment of the utility model, a flow pipe anti-rotation structure of an intelligent stratified water injection and water distributor is disclosed, such as Figures 1 to 7As shown, it includes a flow tube 10, a lower joint 20, an upper joint 30, a pull ring 40, and an outer casing 50; the flow tube 10 is a cylindrical structure with a central cavity, and two arc-shaped plates 11 are respectively arranged at both ends of the flow tube 10, and a mounting ear 12 is arranged on the outer wall of one side of the flow tube 10 close to the end; the lower joint 20 is a cylindrical structure with a central cavity, the lower joint 20 is connected to one end of the flow tube 10, and a first thread 21 is arranged on the outer wall of the end of the lower joint 20 close to the flow tube 10; the upper joint 30 is a cylindrical structure with a central cavity, the upper joint 30 is connected to the other end of the flow tube 10, and an annular groove 31 is arranged on the outer wall of the end of the upper joint 30 close to the flow tube 10; the pull ring 40 is rotatably sleeved on the annular groove 31. 1, a second thread 41 is provided on the outer wall of one end of the pull ring 40 close to the flow tube 10, and a plurality of through-holes 42 are evenly spaced along the circumferential direction on the outer wall of the other end of the pull ring 40; the outer casing 50 is a cylindrical structure with a central cavity, and the outer casing 50 is sleeved on the flow tube 10, and the two ends of the outer casing 50 are respectively connected to the lower joint 20 and the upper joint 30, and the inner wall of the two ends of the outer casing 50 is respectively provided with a third thread 51 and a pre-tightening thread 52; wherein the first thread 21 and the third thread 51 match and are screwed to each other, the second thread 41 and the pre-tightening thread 52 match and are screwed to each other, and the mounting ear 12 is connected to the end face of the lower joint 20; the arc plates 11 at both ends of the flow tube 10 are inserted into the corresponding lower joint 20 and A preliminary limit is formed in the arc groove 14 on the inner wall of the upper joint 30, the mounting ear 12 is aligned with the threaded hole 22 of the lower joint 20, and a screw is passed through the through hole 121 on the mounting ear 12 and screwed into the threaded hole 22 to fix the mounting ear 12 and the end face of the lower joint 20, thereby reinforcing the connection between the flow tube 10 as a whole and the lower joint 20, and preventing the flow tube 10 from deflecting slightly; the crescent wrench can rotate the pull ring 40 on the annular groove 31 of the upper joint 30 with the help of a plurality of through holes 42 opened on the pull ring 40, so that the second thread 41 on the pull ring 40 and the pre-tightening thread 52 on the outer casing 50 are gradually tightened, and the pull ring 40 is tightened inwardly under the external pressure, and the upper joint 30 is tightened under the action of the pull ring 40. The arc plate 11 of the flow tube 10 and the bottom end of the arc groove of the upper joint 30 form an extrusion to increase friction, thereby playing an anti-rotation role. During the specific assembly, the arc plate 11 of the flow tube 10 is first inserted into the arc groove 14 of the lower joint 20, and then the mounting ear 12 is fixed with screws, and then the outer casing 50 is assembled; after the upper half pull ring 43 and the lower half pull ring 44 are assembled into the annular groove 31 of the upper joint 30, the assembly of the pull ring 40 and the upper joint 30 is combined with the spliced ​​outer casing 50 and the lower joint 20 to complete the assembly; this anti-rotation structure is simple and effective, and only needs to process the corresponding threads on the corresponding components, and the assembly is also very convenient, and can be mass-produced, which solves the problems of complex processing technology and inconvenient disassembly during construction in the prior art.

[0025] Furthermore, if Figure 2 and Figure 7As shown, the mounting ear 12 is arranged at the rear end of the arc-shaped plate 11 near one end of the lower joint 20 for easy assembly; a countersunk hole is provided at the center of one end face of the mounting ear 12 away from the lower joint 20, and a through hole 121 penetrating the mounting ear 12 is provided at the bottom end of the countersunk hole, leaving space for later screw fixation; the flow tube 10 also includes two groups of double-circle annular sealing grooves 13, which are respectively provided on the outer side walls of the tail ends of the arc-shaped plate 11 at both ends of the flow tube 10, and a sealing ring is installed in each double-circle annular sealing groove 13, which ensures the sealing of the flow tube 10 when it is connected to the upper joint 30 and the lower joint 20, and prevents water from overflowing or seeping into the joint gap to affect the anti-slip effect.

[0026] Furthermore, if Figures 1 to 6 As shown, an arc groove 14 matching the arc plate 11 is provided on the inner side wall of one end of the lower joint 20 and the upper joint 30 connected to the flow tube 10. The arc plate 11 is inserted into the arc groove 14. The arc groove 14 forms a preliminary limitation on the two arc plates 11, which is convenient for the subsequent installation of other components.

[0027] Furthermore, if Figures 3 to 7 As shown, a threaded hole 22 corresponding to the through hole 121 of the mounting ear 12 is provided on the end surface of the lower joint 20 contacting the flow tube 10, and the lower joint 20 also includes a first double-circle sealing groove 23, and the first double-circle sealing groove 23 is provided on the outer diameter close to one end of the flow tube 10, and contacts the side of the first thread 21 away from the end head; wherein, the mounting ear 12 can be screwed through the through hole 121 to form a threaded connection with the threaded hole 22, further reinforcing the lower joint 20 and the flow tube 10 to avoid deflection during use, and also facilitating the subsequent tightening and installation of other structures such as the outer casing 50, avoiding the flow tube 10 from rotating during the installation process, thereby reducing the overall connection tightness.

[0028] Furthermore, if Figure 6 As shown, the upper joint 30 further includes a second double-circle sealing groove 32 , which is formed on the outer side wall near one end of the flow tube 10 and contacts the side of the annular groove 31 away from the end.

[0029] Furthermore, if Figures 1 to 4 As shown, the pull ring 40 is divided into an upper pull ring 43 and a lower pull ring 44. The upper pull ring 43 and the lower pull ring 44 have a threaded hole and a through hole respectively. The upper pull ring 43 and the lower pull ring 44 are staggeredly connected to each other by two positioning screws. The upper pull ring 43 and the lower pull ring 44 are snap-fitted on the annular groove 31, which ensures their own strength while facilitating manual installation and debugging.

[0030] Furthermore, if Figures 1 to 7As shown, the outer casing 50 is provided with a first annular groove 54 and a second annular groove 55, the first annular groove 54 is provided on the inner side wall of the end near the end of the lower joint 20, and the first annular groove 54 corresponds to the position of the first double-circle sealing groove 23; the second annular groove 55 is provided on the inner side wall of the end near the end of the upper joint 30, and the second annular groove 55 corresponds to the position of the second double-circle sealing groove 32; the arrangement of the first annular groove 54 and the second annular groove 55 can well seal with the sealing rings of the first double-circle sealing groove 23 and the second double-circle sealing groove 32 to prevent water from overflowing; wherein, the third thread 51 is provided on the inner side wall of the outer casing 50, and contacts with the side of the first annular groove 54 away from the end head to correspond to the position of the first thread 21; the pre-tightening thread 52 is provided on the inner diameter of the outer casing 50, and contacts with the side of the second annular groove 55 away from the end head to correspond to the position of the second thread 41; the two sets of threads corresponding to each other make the whole structure relatively stable and easy to install and disassemble.

[0031] During specific use, the staff first installs multiple groups of rubber sealing rings into the two groups of double-circle annular sealing grooves 13 of the flow tube 10, and then inserts the arc plate 11 at one end of the flow tube 10 into the corresponding arc groove 14 of the lower joint 20 to make it relatively stable; rotate the flow tube 10 so that the through hole 121 of the mounting ear 12 of the flow tube 10 corresponds to the threaded hole 22 of the lower joint 20, screw in the screw, and fix the mounting ear 12 to the end face of the lower joint 20; at the same time, the upper half pull ring 43 and the lower half pull ring 44 can be snap-connected to the annular groove 31 of the upper joint 30, and two positioning screws are passed through the through holes of the upper half pull ring 43 and the lower half pull ring 44 to make the two interlaced and connected with each other, so that the pull ring 40 structure can be rotatably rotated on the annular groove 31 of the upper joint 30; then install multiple groups of rubber sealing rings on the lower joint The flow tube 10 is passed through the central cavity of the outer casing 50 in the first double-circle sealing groove 23 of the head 20 and the second double-circle sealing groove 32 of the upper joint 30, and one end of the outer casing 50 is tightened with the lower joint 20, and is screwed together through the third thread 51 of the outer casing 50 and the first thread 21 of the lower joint 20; then the combination of the upper joint 30 and the pull ring 40 is inserted into the other end of the outer casing 50; finally, a crescent wrench is used to rotate the pull ring 40 on the annular groove 31 with the help of multiple through-holes 42 on the pull ring 40, and the second thread 41 of the pull ring 40 and the pre-tightening thread 52 of the outer casing 50 are gradually tightened, so that the upper joint 30 is tightened under the pressure of the pull ring 40, thereby increasing the friction between the inner wall of the arc groove 14 of the upper joint 30 and the contact surface of the arc plate 11 of the flow tube 10, thereby achieving an anti-rotation effect.

[0032] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. An anti-rotation structure for the flow pipe of an intelligent stratified water injection distributor, characterized in that: include: A flow tube (10), the flow tube (10) being a cylindrical structure with a central cavity, two arc-shaped plates (11) being respectively arranged at both ends of the flow tube (10), and a mounting ear (12) being arranged on an outer wall of one side of the flow tube (10) close to the end; A lower joint (20), the lower joint (20) being a cylindrical structure with a central cavity, the lower joint (20) being connected to one end of the flow tube (10), and a first thread (21) being provided on an outer side wall of one end of the lower joint (20) close to the flow tube (10); An upper joint (30), the upper joint (30) being a cylindrical structure with a central cavity, the upper joint (30) being connected to the other end of the flow tube (10), and an annular groove (31) being provided on an outer side wall of one end of the upper joint (30) close to the flow tube (10); A pull ring (40), the pull ring (40) being rotatably sleeved on the annular groove (31), a second thread (41) being provided on an outer wall of one end of the pull ring (40) close to the flow tube (10), and a plurality of through-holes (42) being evenly spaced along the circumferential direction on an outer wall of the other end of the pull ring; An outer protective tube (50), the outer protective tube (50) being a cylindrical structure with a central cavity, the outer protective tube (50) being sleeved on the flow tube (10), the two ends of the outer protective tube (50) being respectively connected to the lower joint (20) and the upper joint (30), and the inner side walls at the two ends of the outer protective tube (50) being respectively provided with a third thread (51) and a pre-tightening thread (52); The first thread (21) and the third thread (51) match and are screwed together, the second thread (41) and the pre-tightening thread (52) match and are screwed together, and the mounting ear (12) is connected to the end face of the lower joint (20).

2. The anti-rotation structure of the flow pipe of the intelligent stratified water injection and water distributor according to claim 1 is characterized in that: The mounting ear (12) is arranged at the rear end of the arc-shaped plate (11) close to one end of the lower joint (20); a countersunk hole is provided at the center of one end surface of the mounting ear (12) away from the lower joint (20); a through hole (121) penetrating the mounting ear (12) is provided at the bottom end of the countersunk hole; the flow pipe (10) further comprises: Two groups of double-circle annular sealing grooves (13) are respectively provided on the outer side walls of the tail ends of the arc-shaped plates (11) at both ends of the flow tube (10), and a sealing ring is installed in each of the double-circle annular sealing grooves (13).

3. The anti-rotation structure of the flow pipe of the intelligent stratified water injection and water distributor according to claim 1 is characterized in that: An arc-shaped groove (14) matching the arc-shaped plate (11) is provided on the inner side wall of one end of the lower joint (20) and the upper joint (30) connected to the flow tube (10), and the arc-shaped plate (11) is inserted into the arc-shaped groove (14).

4. The anti-rotation structure of the flow pipe of the intelligent stratified water injection and water distributor according to claim 2 is characterized in that: A threaded hole (22) corresponding to the through hole (121) of the mounting ear (12) is provided on the end surface of the lower joint (20) contacting the flow tube (10), and the lower joint (20) further comprises: A first double-circle sealing groove (23), the first double-circle sealing groove (23) being formed on the outer diameter of one end of the flow tube (10) and in contact with a side of the first thread (21) away from the end; The mounting ear (12) can be threadedly connected to the threaded hole (22) by means of a screw passing through the through hole (121).

5. The anti-rotation structure of the flow pipe of the intelligent stratified water injection and water distributor according to claim 3 is characterized in that: The upper joint (30) further comprises: A second double-circle sealing groove (32), the second double-circle sealing groove (32) is formed on the outer wall close to one end of the flow tube (10) and contacts the side of the annular groove (31) away from the end.

6. The anti-rotation structure of the flow pipe of the intelligent stratified water injection and water distributor according to claim 1 is characterized in that: The pull ring (40) is divided into an upper pull ring (43) and a lower pull ring (44), and the upper pull ring (43) and the lower pull ring (44) are staggeredly connected to each other through two positioning screws. The upper pull ring (43) and the lower pull ring (44) are snap-fitted on the annular groove (31).

7. The anti-rotation structure of the flow pipe of the intelligent stratified water injection and water distributor according to claim 3 is characterized in that: The outer casing (50) is provided with a first annular groove (54) and a second annular groove (55), wherein the first annular groove (54) is provided on the inner side wall of the end close to one end of the lower joint (20), and the first annular groove (54) corresponds to the position of the first double-circle sealing groove (23); the second annular groove (55) is provided on the inner side wall of the end close to one end of the upper joint (30), and the second annular groove (55) corresponds to the position of the second double-circle sealing groove (32); Wherein, the third thread (51) is provided on the inner wall of the outer casing (50) and contacts the side of the first annular groove (54) away from the end head; the pre-tightening thread (52) is provided on the inner diameter of the outer casing (50) and contacts the side of the second annular groove (55) away from the end head.

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