CN202380985U - Tubular air seal thread joint - Google Patents

Abstract

The utility model relates to a tubular air-tight threaded joint. It includes a casing (2) and a coupling (1), and the end of the external thread of the casing (2) is provided with an external sealing combination including a first tapered surface (11) and a second tapered surface (12) with variable taper surface (4), the end of the outer seal combination surface (4) is provided with a sleeve positioning end surface (9); the root of the inner thread of the coupling (1) is provided with a third tapered surface with variable taper matching the outer seal combination surface (7) and the fourth tapered surface (8), the bottom end of the inner seal combination surface (3) is provided with a coupling anti-torque reverse shoulder (5) that cooperates with the casing positioning end surface (9); the outer seal of the casing The combination surface (4) and the coupling inner sealing combination surface (3) matched with it, as well as the casing positioning end surface (9) and the coupling torque-stop reverse shoulder (5) are all interference fits. The utility model improves the stability of the sealing performance of the sealing surface under tensile load by optimizing the taper of the variable cone surface and the angle of the reverse shoulder.

Description

A tubular airtight threaded joint

technical field

The utility model relates to a thread sealing technology, in particular to an air-tight thread joint used for oil oil pipes and casings used in oil drilling, development and production. the

Background technique

With the development of China's economy, the demand for natural gas is increasing, and the exploitation of natural gas has become an important measure for my country's energy industry. Usually natural gas needs to be extracted from the ground by drilling wells. During the drilling and production process, the casing used to fix the well wall and the tubing used for gas production are long strings connected by threads one by one. Each threaded joint must ensure a reliable airtight seal performance. the

At present, API threads are widely used in oil fields, including round threads (LTC, STC) and buttressed threads (BTC). The API thread is a tapered thread, which mainly relies on the contact pressure generated by the interference fit of the mating surface of the mating thread to obtain an effective seal. Due to structural design and the existence of machining tolerances, there is a fit gap between the mating surfaces of API threads. Essentially, API threads do not have fluid (especially gas) sealing capabilities, while API threads can seal fluids at a certain pressure, mainly by using solid particles in thread grease, or by plating copper, zinc and other soft metals to reduce the pressure. these gaps. However, thread grease is easy to volatilize or deteriorate at high temperature or during long-term use, resulting in a decrease in thread sealing. the

If there is no sealing surface for the purpose of sealing, it is difficult to effectively seal the gas for a long time only by relying on the tight fit of the thread. At present, there are mainly two methods to adjust the sealing structure at home and abroad: one is to adopt a variable cone sealing structure; the other is to use a reverse angle shoulder. Both the tapered surface structure and the reverse shoulder can improve the contact pressure distribution on the main sealing surface of the special threaded joint to a certain extent, but when the tensile load is applied, neither method alone can improve the joint sealing more effectively Effect. the

Utility model content

The utility model provides a special air-tight threaded joint, which combines a variable cone surface and a reverse shoulder structure to realize the purpose of blocking high-pressure gas and preventing leakage when oil pipes or casings are connected. the

The tubular air-tight threaded joint of the utility model comprises a casing 2 with an external thread at one end and a collar 1 with an internal thread at the other end, and is characterized in that:

The end of the external thread of the casing 2 is provided with an outer sealing combination surface 4, and the end of the outer sealing combination surface 4 is provided with a sleeve positioning end surface 9, and the outer sealing combination surface 4 includes a first taper with variable taper Face 11 and second cone face 12;

The root of the inner thread of the coupling 1 is provided with an inner seal combination surface 3 that cooperates with the outer seal combination surface 4, and the bottom end of the inner seal combination surface 3 is provided with a joint that cooperates with the casing positioning end surface 9. Hoop stop torque reverse shoulder 5;

The inner sealing combination surface 3 of the coupling includes the third tapered surface 7 and the fourth tapered surface 8 with variable taper that cooperate with the outer sealing combination surface 4; the outer sealing combination surface 4 of the sleeve and the matching The coupling inner seal combination surface 3 is an interference fit, and the sleeve positioning end surface 9 and the coupling torque-stop reverse shoulder 5 are an interference fit. the

In specific implementation,

The taper of the second tapered surface 12 and the fourth tapered surface 8 close to the thread can be 1/10, and the tapered surface of the first tapered surface 11 and the third tapered surface 7 away from the thread can be 1/3. the

The angle between the sleeve positioning end face 9 and the axis of the sleeve 2 may be -5°. the

The angle between the anti-torque shoulder 5 of the collar and the axis of the casing 2 may be -5°. the

The radial interference of the inner sealing combined surface 3 and the tapered outer sealing combined surface 4 may be 0.23-0.31mm. the

The axial interference between the positioning end surface 9 of the sleeve 2 and the anti-torque shoulder 5 of the coupling 1 may be 0.05mm. the

The utility model can be widely used in the air-tight threaded joints of oil pipes, gas pipes and casing pipes used in oil and natural gas drilling, development and production. the

The effect of the utility model is that by combining the variable taper surface and the reverse shoulder structure, and by optimizing the taper of the variable taper surface and the angle of the reverse shoulder, the stability of the sealing performance of the sealing surface under tensile load is improved. At the same time, because the thread in the threaded joint only acts as a connection and does not act as a seal, the number of machine tightening turns can be reduced, the stress level of the thread is reduced, stress corrosion is avoided, and the anti-bonding ability is also improved. the

Description of drawings

Fig. 1 is a sealing state diagram of an embodiment of the utility model. the

Fig. 2 is a schematic structural view of the inner sealing composite surface in the embodiment of the present invention;

Fig. 3 is a schematic diagram of the structure of the outer sealing combined surface in the embodiment of the utility model. the

Detailed ways

As shown in Figure 1, Figure 2, and Figure 3, the special airtight threaded joint includes a threaded coupling 1 and a pipe body 2. The end of the combination surface 4 is provided with a pipe body positioning end surface 9; the root of the inner thread of the coupling 1 is provided with an inner seal combination surface 3 that cooperates with the outer seal combination surface 4, and the bottom of the inner seal combination surface 3 The end is provided with a coupling anti-torque reverse shoulder 5 that cooperates with the positioning end face 9 of the pipe body; the outer sealing combination surface 4 includes a first tapered surface 11 and a second tapered surface 12 with variable taper; the inner sealing combination The surface 3 includes a third tapered surface 7 and a fourth tapered surface 8 with a variable taper that cooperate with the outer sealing combined surface 4; the taper of the third tapered surface 7 and the first tapered surface 11 is 1/3, and the The taper of the fourth tapered surface 8 and the second tapered surface 12 is 1/10; the positioning end surface 9 of the pipe body is a tapered surface, and the angle between the tapered surface and the axis of the casing is -5°; the coupling stop torque The reverse shoulder 5 is a conical surface, and the angle between the coupling stop torque reverse shoulder 5 and the axis of the casing 2 is -5°; the position between the pipe body positioning end surface 9 and the first conical surface 11 is an outer circle The arc transition surface 10; the inner arc transition surface 6 is between the coupling stop torque reverse shoulder 5 and the third tapered surface 7; the radius of the outer arc transition surface 10 is greater than 0.5mm; the inner The radius of the arc transition surface 6 is less than 0.5mm. When the pipe body and the coupling are tightened and sealed, the inner sealing combination surface 3 and the matching outer sealing combination surface 4 have an interference fit, and the radial interference of the interference fit is 0.23-0.31 mm; The body positioning end face 9 and the collar stop torque reverse shoulder 5 adopt an interference fit, and the axial interference of the interference fit is 0.05mm. the

Claims (7)

1. tubulose air-tight seal screw joint comprises that an end has the box cupling (1) that externally threaded sleeve pipe (2) and another end have internal thread, is characterized in that:

The externally threaded end of said sleeve pipe (2) is provided with external seal combinatorial surface (4), and the end of said external seal combinatorial surface (4) is provided with sleeve pipe location end face (9), and said external seal combinatorial surface (4) comprises first conical surface (11) and second conical surface (12) of taper mutation;

The root of said box cupling (1) internal thread is provided with the interior seal combination face (3) that cooperates with said external seal combinatorial surface (4), and the bottom of said interior seal combination face (3) is provided with the box cupling that cooperates with said sleeve pipe location end face (9) and ends the reverse shoulder of moment of torsion (5);

Seal combination face (3) comprises the third hand tap face (7) and the 4th conical surface (8) of the taper mutation that cooperates with said external seal combinatorial surface (4) in the said box cupling; The external seal combinatorial surface (4) of said sleeve pipe and the interior seal combination face (3) of the box cupling that cooperates with it are interference fit, and said sleeve pipe location end face (9) ends the reverse shoulder of moment of torsion (5) with box cupling and is interference fit.

2. air-tight seal screw joint as claimed in claim 1 is characterized in that:

Near described second conical surface (12) of screw thread and the conical surface tapering of the 4th conical surface (8) is 1/10, is 1/3 away from described first conical surface (11) of screw thread and the conical surface tapering of third hand tap face (7).

3. air-tight seal screw joint as claimed in claim 1 is characterized in that:

Said sleeve pipe location end face (9) is-5 ° with the angle of sleeve pipe (2) axis.

4. air-tight seal screw joint as claimed in claim 1 is characterized in that:

The angle that said box cupling ends reverse shoulder of moment of torsion (5) and sleeve pipe (2) axis is-5 °.

5. air-tight seal screw joint as claimed in claim 1 is characterized in that:

The radial interference amount of the seal combination face (3) and described external seal combinatorial surface (4) conical surface is 0.23～0.31mm in described.

6. air-tight seal screw joint as claimed in claim 1 is characterized in that:

Said sleeve pipe (2) location end face (9) is 0.05mm with the axial magnitude of interference that described box cupling (1) ends the reverse shoulder of moment of torsion (5).

7. air-tight seal screw joint as claimed in claim 2 is characterized in that:

Said sleeve pipe location end face (9) is-5 ° with the angle of sleeve pipe (2) axis;

The angle that said box cupling ends reverse shoulder of moment of torsion (5) and sleeve pipe (2) axis is-5 °;

The radial interference amount of the seal combination face (3) and described external seal combinatorial surface (4) conical surface is 0.23～0.31mm in described;

Said sleeve pipe (2) location end face (9) is 0.05mm with the axial magnitude of interference that described box cupling (1) ends the reverse shoulder of moment of torsion (5).

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