Coupling-free direct-connection screwed joint

Abstract

The utility model discloses a coupling-free direct-connection screwed joint which is used for connecting adjacent oil pipes and comprises a male buckle and a female buckle, the male buckle is arranged at one end of one oil pipe, the inner diameter of the male buckle is the same as that of the oil pipe, the outer diameter of the male buckle is thickened and upset outwards, and a first connecting conical surface is arranged on the outer surface of the male buckle; the first connecting conical surface is sequentially provided with an outer reverse torque shoulder, a trapezoidal external thread, an outer tool withdrawal groove and an outer metal interference fit conical surface in the axial direction; a right-angle shoulder end is arranged on the male buckle, and an arc transition is arranged between the right-angle shoulder end and the first connecting conical surface; the female buckle is arranged at the opposite end of the other oil pipe, the outer diameter of the female buckle is thickened outwards, a second connecting conical surface is arranged on the inner surface of the female buckle, and the second connecting conical surface is sequentially provided with a right-angle shoulder, an inner metal interference conical surface, an inner tool withdrawal groove and a trapezoidal inner thread in the axial direction. The outer diameter utilization rate and the sealing performance of the oil pipe can be effectively improved under the condition that the outer diameter of the oil pipe is limited.

Description

Technical Field

[0001] The utility model relates to a coupling-free direct-connection threaded joint, belonging to the technical field of oil pipe threaded connection. Background Art

[0002] At present, in order to meet the increasing gas production demand in the exploitation of old wells, it is necessary to increase the gas sealing effect. Since the gas production of a single old well is very large, it is necessary to increase the outer diameter of the pipeline as much as possible to meet the production demand.

[0003] After searching the prior art, it was found that the Chinese patent with announcement number CN221053636U disclosed a high-torque-resistant sealing joint for oil casing. The patent achieved the sealing effect of oil casing under large torque, but it was found during use that in the traditional old well mining technology, since the airtight seal with coupling relies on the outer diameter of the coupling to achieve sealing, when it is necessary to increase the gas production of a single well, that is, to increase the outer diameter of the pipeline to meet higher production needs, the outer diameter of the coupling becomes a limiting factor. This limitation not only affects the effective extraction of gas, but also limits the improvement of production efficiency. Summary of the invention

[0004] The technical problem to be solved by the utility model is to overcome the defects of the prior art and provide a coupling-free direct-connected threaded joint, which can effectively improve the outer diameter utilization rate and sealing performance of the pipeline when the outer diameter of the oil pipeline is limited.

[0005] In order to solve the above technical problems, the technical solution of the utility model is: a couplingless straight-connected threaded joint for connecting connected oil pipes, comprising:

[0006] A male buckle, the male buckle is arranged on one end of one of the oil pipes, the inner diameter of the male buckle is the same as the inner diameter of the oil pipe, the outer diameter is thickened outwardly, and a first connecting cone surface is provided on the outer surface, and the first connecting cone surface is provided with an external reverse torque shoulder, a trapezoidal external thread, an external tool backing groove and an external metal interference fit cone surface in sequence along the axial direction;

[0007] The male buckle is provided with a right-angle shoulder end, and a circular arc transition is provided between the right-angle shoulder end and the first connecting cone surface;

[0008] A box buckle, which is arranged on the opposite end of the other oil pipe, the outer diameter of the box buckle is thickened outwards, and a second connecting cone surface is provided on the inner surface, and the second connecting cone surface is provided with a right-angle shoulder, an inner metal interference cone surface, an inner cutter groove and a trapezoidal internal thread in sequence along the axial direction;

[0009] The female buckle is provided with a reverse torque shoulder end, and an arc transition is provided between the reverse torque shoulder end and the second connecting cone surface;

[0010] When the trapezoidal external thread of the male buckle is fully engaged with the trapezoidal internal thread of the female buckle, the external reverse torque shoulder and the reverse torque shoulder end are suitable for contacting to form a first anti-torsion sealing surface, the right-angle shoulder end and the right-angle shoulder are suitable for contacting to form a second anti-torsion sealing surface, and the inner metal interference cone surface of the female buckle and the outer metal interference fit cone surface of the male buckle are suitable for forming an interference fit.

[0011] Furthermore, in order to enhance the stability of the joint and the uniform thickness of the connecting section, after the male buckle and the female buckle are tightly matched, the combined radial wall thickness of the male buckle and the female buckle forms an equal thickness structure.

[0012] Further, in order to enhance the sealing performance, the couplingless direct-connect threaded joint further includes a split sealing ring, wherein the split sealing ring includes:

[0013] A first sealing ring, the first sealing ring being installed in the outer backing groove of the male buckle;

[0014] A second sealing ring, the second sealing ring being installed in the inner backing groove of the female buckle;

[0015] The first sealing ring is suitable for connecting with the second sealing ring to form a split sealing ring.

[0016] Further, in order to increase the rotational friction force, a plurality of first locking friction teeth are provided on the outer surface of the first sealing ring, and a plurality of second locking friction teeth cooperating with the first locking friction teeth are provided on the inner surface of the second sealing ring;

[0017] The first locking friction tooth is suitable for meshing with the second locking friction tooth.

[0018] Furthermore, a first single-sided sealing protrusion is provided on the outer side of one end of the first sealing ring;

[0019] A second single-side sealing protrusion is provided on the inner side of one end of the second sealing ring;

[0020] When the first sealing ring and the second sealing ring are connected to form a complete split sealing ring, the first single-side sealing protrusion of the first sealing ring abuts against the other end of the second sealing ring.

[0021] The second single-side sealing protrusion of the second sealing ring abuts against the other end of the first sealing ring.

[0022] Furthermore, the couplingless straight-connected threaded joint further comprises a reverse shoulder sealing fastener, wherein the reverse shoulder sealing fastener is mounted on the male buckle and is located between the external reverse torque shoulder and the trapezoidal external thread;

[0023] When the male buckle is tightly matched with the female buckle, the reverse shoulder sealing fastener abuts against the second connecting cone surface of the female buckle, and abuts between the trapezoidal internal thread of the female buckle and the reverse torque shoulder end.

[0024] Furthermore, the right-angle shoulder end and the inner diameter surface of the male buckle are chamfered.

[0025] Furthermore, a specific range of the inclined surface of the external reverse torque shoulder is provided, and the angle between the inclined surface of the external reverse torque shoulder of the male buckle and the axis of the male buckle is 25° to 35°.

[0026] Furthermore, in order to reduce stress concentration and extend service life, a first stress relief arc is provided on the outer reverse torque shoulder of the male buckle and the first connecting cone surface;

[0027] A second stress relief arc is provided between the right-angle shoulder of the female buckle and the second connecting conical surface.

[0028] By adopting the above technical solution, the utility model has the following beneficial effects:

[0029] In the present invention, in order to maximize the outer diameter of the oil pipe when the outer diameter of the oil pipe is limited, a coupling-free direct-connected threaded joint is used. At the joint between the male buckle and the female buckle of the oil pipe, the outer diameter of the oil pipe is roughened and then the thread is processed. The engagement of the trapezoidal external thread of the male buckle and the trapezoidal internal thread of the female buckle ensures the connection stability. The right-angle shoulder on the female buckle and the external reverse torque shoulder of the male buckle form a high-efficiency anti-torsion structure. The interference fit between the inner metal interference cone surface of the female buckle and the outer metal interference fit cone surface of the male buckle also ensures the sealing performance.

[0030] In summary, the utility model effectively improves the outer diameter utilization and sealing performance of the pipeline when the outer diameter of the oil pipe is limited, and effectively improves the torsion resistance of the oil pipe connection, thereby significantly improving work efficiency and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The structure of the embodiment 1 of the non-coupling direct-connect threaded joint of the utility model is shown in FIG. Figure 1 ;

[0032] Figure 2 The structure of the embodiment 1 of the non-coupling direct-connect threaded joint of the utility model is shown in FIG. Figure 2 ;

[0033] Figure 3 It is a structural schematic diagram of Example 2 of a coupling-free direct-connected threaded joint of the utility model;

[0034] Figure 4 for Figure 3 A partial enlarged view of the middle A part;

[0035] Figure 5 for Figure 3 A partial enlarged view of part B in the middle;

[0036] Figure 6 It is a structural schematic diagram of the trapezoidal external thread of the male buckle of the coupling-free direct-connection threaded joint of the utility model;

[0037] Figure 7 It is a three-dimensional structural schematic diagram of a split sealing ring of a coupling-free direct-connected threaded joint of the utility model;

[0038] Figure 8 This is a partial enlarged view of part C in Figure 7. DETAILED DESCRIPTION

[0039] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings.

[0040] Example 1

[0041] like Figure 1-8 As shown, a couplingless straight-connect threaded joint is used for connecting adjacent oil pipes, comprising:

[0042] A male buckle 1 is arranged at one end of one of the oil pipes. The inner diameter of the male buckle 1 is the same as the inner diameter of the oil pipe, and the outer diameter is thickened and swollen outwards. A first connecting cone surface is arranged on the outer surface. The first connecting cone surface is provided with an external reverse torque shoulder 11, a trapezoidal external thread 12, an external undercut groove 13 and an external metal interference fit cone surface 14 in sequence along the axial direction.

[0043] The male buckle 1 is provided with a right-angle shoulder end 15, and a circular arc transition is provided between the right-angle shoulder end 15 and the first connecting cone surface;

[0044] A box buckle 2 is arranged on the opposite end of the other oil pipe. The outer diameter of the box buckle 2 is thickened and swollen outwards, and a second connecting cone surface is provided on the inner surface. The second connecting cone surface is provided with a right-angle shoulder 21, an inner metal interference cone surface 22, an inner cutter groove 23 and a trapezoidal inner thread 24 in sequence along the axial direction;

[0045] The female buckle 2 is provided with a reverse torque shoulder end 25, and a circular arc transition is provided between the reverse torque shoulder end 25 and the second connecting cone surface;

[0046] When the trapezoidal external thread 12 of the pin buckle 1 is fully engaged with the trapezoidal internal thread 24 of the box buckle 2, the external reverse torque shoulder 11 and the reverse torque shoulder end 25 are suitable for contacting to form a first anti-torsion sealing surface, the right-angle shoulder end 15 and the right-angle shoulder 21 are suitable for contacting to form a second anti-torsion sealing surface, and the inner metal interference cone surface 22 of the box buckle 2 and the outer metal interference fit cone surface 14 of the pin buckle 1 are suitable for forming an interference fit.

[0047] In this embodiment, if Figure 1-3 and Figure 6 As shown, in order to maximize the outer diameter of the oil pipe when the outer diameter of the oil pipe is limited, a coupling-free direct threaded joint is used. At the joint between the male buckle 1 and the female buckle 2 of the oil pipe, the outer diameter of the oil pipe is roughened and then the thread is processed. The engagement of the trapezoidal external thread 12 of the male buckle 1 and the trapezoidal internal thread 24 of the female buckle 2 ensures the connection stability. The right-angle shoulder 21 on the female buckle 2 and the external reverse torque shoulder 11 of the male buckle 1 form a double torque shoulder, forming an efficient anti-torsion structure. The interference fit between the inner metal interference cone surface 22 of the female buckle 2 and the outer metal interference fit cone surface 14 of the male buckle 1 ensures the sealing performance.

[0048] The outer diameter of the joint between the pin 1 and the box 2 is smaller than the outer diameter of the coupling of the same specification, and the diameter meets the API requirements. The thickness is equivalent to the size of API EU.

[0049] The trapezoidal external thread 12 and the trapezoidal internal thread 24 have fast fastening speed, low stress level, and good anti-sticking performance. In some embodiments, the trapezoidal external thread 12 and the trapezoidal internal thread 24 can also be partial trapezoidal threads or hook threads.

[0050] Specifically, Figure 1 and Figure 3 As shown, after the male buckle 1 and the female buckle 2 are tightly matched, the combined radial wall thickness of the male buckle 1 and the female buckle 2 forms an equal thickness structure.

[0051] In this embodiment, if Figure 1 and Figure 3 As shown, the equal thickness structure formed by the tight fit of the male buckle 1 and the female buckle 2 provides a uniform outer surface, which is convenient for installation and connection.

[0052] Specifically, Figure 1-3 As shown, a first stress relief arc is provided on the outer reverse torque shoulder 11 of the male buckle 1 and the first connecting cone surface;

[0053] A second stress relief arc is provided between the right-angle shoulder 21 of the female buckle 2 and the second connecting conical surface.

[0054] In this embodiment, the main functions of the first stress relief arc and the second stress relief arc are to reduce stress concentration and improve the overall strength and service life of the joint.

[0055] Example 2

[0056] This embodiment is basically the same as Embodiment 1, except that:

[0057] Specifically, Figure 1-3 and Figure 6-8 As shown, the coupling-free direct-connect threaded joint also includes a split sealing ring 3, which includes:

[0058] A first sealing ring 31, the first sealing ring 31 is installed in the outer backing groove 13 of the male buckle 1;

[0059] A second sealing ring 32, which is installed in the inner backing groove 23 of the female buckle 2;

[0060] The first sealing ring 31 is suitable for connecting with the second sealing ring 32 to form a complete split sealing ring 3 .

[0061] Specifically, Figure 1-3 and Figure 6-8 As shown, a plurality of first locking friction teeth are provided on the outer surface of the first sealing ring 31, and a plurality of second locking friction teeth cooperating with the first locking friction teeth are provided on the inner surface of the second sealing ring 32;

[0062] The first locking friction tooth is suitable for meshing with the second locking friction tooth.

[0063] In this embodiment, if Figure 1-3 and Figure 6-8 As shown in the figure, the split seal ring 3 of the couplingless direct-connected threaded joint first forms an additional sealing barrier between the male buckle 1 and the female buckle 2 through the combination of the first sealing ring 31 and the second sealing ring 32, effectively preventing fluid leakage. Secondly, the split design facilitates installation and replacement, improving maintenance efficiency. Finally, the one-way locking structure of the first locking friction tooth and the second locking friction tooth ensures the stability of the seal ring during use and prevents accidental loosening.

[0064] Specifically, Figure 8 As shown, a first single-sided sealing protrusion is provided on the outer side of one end of the first sealing ring 31;

[0065] A second single-side sealing protrusion is provided inside one end of the second sealing ring 32;

[0066] When the first sealing ring 31 and the second sealing ring 32 are connected to form a complete split sealing ring 3 , the first single-sided sealing protrusion of the first sealing ring 31 abuts against the other end of the second sealing ring 32 , and the second single-sided sealing protrusion of the second sealing ring 32 abuts against the other end of the first sealing ring 31 .

[0067] In this embodiment, if Figure 7-8 As shown, the first unilateral sealing protrusion and the second unilateral sealing protrusion on the first sealing ring 31 and the second sealing ring 32 are for enhancing the sealing performance of the split sealing ring 3. This bidirectional sealing structure forms an additional sealing barrier on both sides of the split sealing ring 3, effectively preventing fluid leakage in the forward and reverse directions.

[0068] Specifically, Figure 1-3 and Figure 6-5As shown, the couplingless straight-connected threaded joint further includes a reverse shoulder sealing fastener 4, which is installed on the pin 1 and is located between the external reverse torque shoulder 11 and the trapezoidal external thread 12;

[0069] When the male buckle 1 is tightly matched with the female buckle 2 , the reverse shoulder sealing fastener 4 abuts against the female buckle 2 .

[0070] In this embodiment, if Figure 1-3 and Figure 6-5 As shown, the design of the reverse shoulder sealing fitting 4 not only enhances the sealing performance of the joint, but also abuts between the trapezoidal internal thread 24 of the box buckle 2 and the reverse torque shoulder end 25, so that when the male buckle 1 and the box buckle 2 are tightly matched, the external reverse torque shoulder 11 and the reverse torque shoulder end 25 form a first anti-torsion sealing surface in close contact.

[0071] Specifically, Figure 1-4 As shown, the right-angle shoulder end 15 and the inner diameter surface of the male buckle 1 are chamfered.

[0072] In this embodiment, if Figure 1-4 As shown, the chamfers designed on the right-angle shoulder end 15 and the inner diameter surface of the male buckle 1 are designed to facilitate interference fit and reduce stress concentration.

[0073] Specifically, Figure 1-3 As shown, the angle between the inclined surface of the external reverse torque shoulder 11 of the pin buckle 1 and the axis of the oil pipe is 30°, wherein the inclined surface is inclined toward the box buckle 2 side.

[0074] In this embodiment, if Figure 2 As shown, the angle between the inclined surface of the external reverse torque shoulder 11 and the axis of the oil pipe can range from 25° to 35°.

[0075] Example 3

[0076] This embodiment is basically the same as Embodiment 1, except that:

[0077] In this embodiment, if Figure 2 and Figure 6 As shown, the thread angle between the trapezoidal external thread 12 and the trapezoidal internal thread 24 is b1, the value range of b1 can be 3° to 5°, preferably 4°, and the thread bearing surface angle between the trapezoidal external thread 12 and the trapezoidal internal thread 24 is b2, the value range of b2 can be 15° to 25°, preferably 20°.

[0078] The specific embodiments described above further illustrate the technical problems, technical solutions and beneficial effects solved by the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A couplingless straight-connect threaded joint for connecting adjacent oil pipes, characterized in that: include: A male buckle (1), the male buckle (1) is arranged on one end of one of the oil pipes, the inner diameter of the male buckle (1) is the same as the inner diameter of the oil pipe, the outer diameter is thickened and swollen outwards, and a first connecting cone surface is provided on the outer surface, the first connecting cone surface is provided with an external reverse torque shoulder (11), a trapezoidal external thread (12), an external tool withdrawal groove (13) and an external metal interference fit cone surface (14) in sequence along the axial direction, the male buckle (1) is provided with a right-angle shoulder end (15), and a circular arc transition is provided between the right-angle shoulder end (15) and the first connecting cone surface; A box buckle (2), the box buckle (2) being arranged on an opposite end of another oil pipe, the outer diameter of the box buckle (2) being thickened and swollen outwards, and a second connecting cone surface being provided on the inner surface, the second connecting cone surface being provided with a right-angle shoulder (21), an inner metal interference cone surface (22), an inner tool-relief groove (23) and a trapezoidal internal thread (24) in sequence along the axial direction, the box buckle (2) being provided with a reverse torque shoulder end (25), and a circular arc transition being provided between the reverse torque shoulder end (25) and the second connecting cone surface; When the trapezoidal external thread (12) of the male buckle (1) is fully meshed with the trapezoidal internal thread (24) of the female buckle (2), the external reverse torque shoulder (11) and the reverse torque shoulder end (25) are suitable for contacting to form a first anti-torsion sealing surface, the right-angle shoulder end (15) and the right-angle shoulder (21) are suitable for contacting to form a second anti-torsion sealing surface, and the inner metal interference cone surface (22) of the female buckle (2) and the outer metal interference fit cone surface (14) of the male buckle (1) are suitable for forming an interference fit.

2. The couplingless straight-connect threaded joint according to claim 1, characterized in that: After the male buckle (1) and the female buckle (2) are tightly matched, the combined radial wall thickness of the male buckle (1) and the female buckle (2) forms an equal thickness structure.

3. The couplingless straight-connect threaded joint according to claim 1, characterized in that: It also includes a split sealing ring (3), wherein the split sealing ring (3) includes: A first sealing ring (31), the first sealing ring (31) being installed in an outer cutter recess (13) of the male buckle (1); A second sealing ring (32), the second sealing ring (32) being installed in the inner backing groove (23) of the female buckle (2); The first sealing ring (31) is suitable for connecting with the second sealing ring (32) to form a split sealing ring (3).

4. The couplingless straight-connect threaded joint according to claim 3, characterized in that: A plurality of first locking friction teeth are provided on the outer surface of the first sealing ring (31), and a plurality of second locking friction teeth cooperating with the first locking friction teeth are provided on the inner surface of the second sealing ring (32); The first locking friction tooth is suitable for meshing with the second locking friction tooth.

5. The couplingless straight-connect threaded joint according to claim 3, characterized in that: A first single-sided sealing protrusion is provided on the outer side of one end of the first sealing ring (31); A second single-sided sealing protrusion is provided on the inner side of one end of the second sealing ring (32); When the first sealing ring (31) and the second sealing ring (32) are connected to form a split sealing ring (3), the first single-sided sealing protrusion of the first sealing ring (31) abuts against the other end of the second sealing ring (32), and the second single-sided sealing protrusion of the second sealing ring (32) abuts against the other end of the first sealing ring (31).

6. The couplingless straight-connect threaded joint according to claim 1, characterized in that: It also includes a reverse shoulder sealing fastener (4), which is mounted on the male buckle (1) and is located between the external reverse torque shoulder (11) and the trapezoidal external thread (12); When the male buckle (1) and the female buckle (2) are tightly matched, the reverse shoulder sealing fastener (4) abuts against the female buckle (2).

7. The couplingless straight-connect threaded joint according to claim 1, characterized in that: The right-angle shoulder end (15) and the inner diameter surface of the male buckle (1) are chamfered.

8. The couplingless straight-connect threaded joint according to claim 1, characterized in that: The angle between the inclined surface of the external reverse torque shoulder (11) of the male buckle (1) and the axis of the male buckle (1) is 25° to 35°.

9. The couplingless straight-connect threaded joint according to claim 1, characterized in that: A first stress relief arc is provided on the outer reverse torque shoulder (11) of the male buckle (1) and the first connecting cone surface; A second stress relief arc is provided between the right-angle shoulder (21) of the female buckle (2) and the second connecting conical surface.

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