CN209942756U

CN209942756U - Simple anti-over-torsion air-tight seal threaded joint

Info

Publication number: CN209942756U
Application number: CN201821327499.7U
Authority: CN
Inventors: 白雪娥; 穆增利
Original assignee: DALIPAL PIPE Co
Current assignee: DALIPAL PIPE Co
Priority date: 2018-08-17
Filing date: 2018-08-17
Publication date: 2020-01-14
Anticipated expiration: 2028-08-17

Abstract

The utility model relates to an anti airtight screwed joint of turning round of simple and easy type belongs to oil casing threaded connection technical field. The joint consists of a female joint and a male joint, wherein an internal thread, a cylindrical hole, a first transition arc and a first torque shoulder are machined on the female joint; the male joint is provided with an external thread, a transition inclined plane, a transition circular arc II, a torque shoulder II and an inner wall inclined plane. The threads of the male connector and the female connector are standard API BC threads without a sealing surface, the pitch diameter of the external threads is the pitch diameter of the API standard threads, the pitch diameter of the internal threads is larger than the pitch diameter of the standard API threads, the stress of the internal threads and the external threads is reduced while the connection function is born, the first torque shoulder and the second torque shoulder adopt a negative angle design to improve the sealing performance and the torsion resistance of the connectors, and the connector has the advantages of simple structure, high processing and measuring efficiency, good air tightness, strong torsion resistance, low manufacturing cost and the like.

Description

Simple anti-over-torsion air-tight seal threaded joint

Technical Field

The utility model relates to an anti airtight screwed joint of turning round of simple and easy type belongs to oil casing threaded connection technical field.

Background

The oil casing pipe column is under the ground to bear the action of various loads such as tension, compression, bending, internal pressure, external pressure and the like for a long time, and the threaded connection part is the weakest link in the pipe column. Currently, oil casing threaded joints can be classified into API threaded joints and special threaded joints. The API threaded connector is produced and used according to API standards, has the advantages of convenience in processing and detection and low cost, but has the defects of low connection efficiency, unreliable air sealing performance, poor torsion resistance and the like. Therefore, manufacturers develop special threaded joints with better air tightness and over-twisting resistance, but the special threaded joints are complex in production process, difficult to detect and high in cost, and low-pressure, low-permeability and low-yield oil and gas field development is not suitable for special threaded joints with high cost, but the API standard joints cannot meet the mining requirements, so that at present, all manufacturers develop economical or simple air-tight over-twisting-resistant threads without sealing surfaces.

The search of the prior art documents shows that the patent with the publication number of CN201120551614 and the name of 'a gas seal threaded joint for low-pressure gas field' discloses a threaded joint which forms gas seal at a thread taper position by adopting a method of increasing thread height and internal thread taper on the basis of API round threads, and has the defects that: 1. the round thread has poor connection strength, and after the tooth height is increased, the tooth side contact surface is increased, so that thread gluing is easy to generate; 2. the production cost is high, and the common domestic numerical control lathe cannot realize variable-cone machining.

The Chinese patent with the granted publication number of CN207363612U and the name of 'an economic airtight threaded connector' discloses an economic airtight thread which can be interchanged with API BC, and is characterized in that a right-angle torque shoulder is added, a cylindrical hole is arranged on a female connector, the diameter of the cylindrical hole is the same as the diameter of the tooth bottom of an adjacent internal thread, and airtight sealing is carried out through interference fit of the torque shoulder. The disadvantages are that: 1. the diameter of the cylindrical hole is the same as the diameter of the tooth bottom of the adjacent internal thread, so that the front three teeth of the external thread are easily damaged during screwing; 2. the threaded joint can not meet the requirement of over-twisting resistance at the same time, and when the threads are over-twisted, the diameter of a pipe end is reduced and the threads are damaged easily at the torque shoulder, so that the threaded joint is not favorable for repeated use.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the technical defect and providing an airtight screwed joint that joint strength is high, simple structure, be convenient for process, and anti excessively turning round. In order to achieve the above purpose, the technical scheme of the utility model is that: a simple anti-over-torsion air-tight seal threaded joint comprises a female joint and a male joint, wherein an inner thread, a cylindrical hole, a transition circular arc I and a torque shoulder I are sequentially processed on the inner wall of the female joint; the outer wall of the male connector is sequentially processed with an external thread, a transition inclined plane, a transition circular arc II, a torque shoulder II and an inner wall inclined plane. The root of a torque shoulder I of the female joint is designed with a transition circular arc I; the top of the torque shoulder II of the male joint is provided with a transition circular arc II; the first torque shoulder and the second torque shoulder are negative-angle torque shoulders. After the female joint and the male joint are screwed, the internal thread and the external thread are in radial interference fit, the interference magnitude is 0.2-0.5 mm, and the connecting function is mainly realized; the first torque shoulder and the second torque shoulder are in axial interference fit to play a sealing role, and meanwhile, the torsion resistance of the joint can be remarkably improved by adopting a negative angle design.

Furthermore, the pitch diameter of the internal thread is 0.1 ~ 0.3.3 mm larger than that of the external thread, and the interference magnitude between the internal thread and the external thread can be properly reduced by increasing the pitch diameter of the internal thread in a tightening state, so that the torque borne by the thread is shared to a torque shoulder, the stress level of the thread is reduced, and the thread sticking risk is reduced.

Furthermore, the inclination angle theta of the first torque shoulder and the second torque shoulder is-3 degrees to-8 degrees. The anti-compression device has the effects of preventing the diameter reduction and deformation of the threaded pipe end under the over-torque condition and can improve the anti-compression capability of the joint.

Furthermore, the radius of the first transition concave arc is 1.4-1.8 mm, and the radius of the second transition convex arc is 0.4-0.8 mm. The device can provide a strain space under complex working conditions, and effectively protects the sealing effect of the first torque shoulder and the second torque shoulder.

Furthermore, the length of a cylindrical hole of the female joint is 8 ~ 12mm, the diameter of the cylindrical hole is 0.4-0.7 mm larger than the diameter of the tooth bottom of the thread at the position, the cylindrical hole is arranged on the female joint, machining and tool retracting are facilitated, the diameter of the cylindrical hole is 0.4-0.7 mm larger than the diameter of the tooth bottom of the adjacent internal thread, the problem that the thread is damaged due to interference between the male joint and the female joint in an over-torque state can be solved while the joint connection strength is not affected, and the over-torque resistance of the joint is enhanced.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the female connector and the male connector both adopt API BC threads, so that the processing is easy, a processing cutter and a checking and measuring tool can be universal with the API BC threads, the measurement is convenient, the processing can be realized by a common numerical control lathe, and the production cost is low; the risk of thread gluing is low; the torque shoulder design of the negative angle improves the sealing capacity of the joint, the sealing capacity can reach more than 70-80% of that of a special buckle, the diameter of a cylindrical hole of the female joint is larger than that of a thread tooth bottom, the diameter shrinkage and damage of a pipe thread caused by thread interference under the over-twisting condition are avoided, and the anti-torque capacity of the joint is obviously improved through the design.

Drawings

Fig. 1 is an axial sectional view of the joint of the present invention.

Figure 2 is a magnified view of the torque shoulder area a of the present invention.

In the figure: 1. a female joint; 2. an internal thread; 3. a cylindrical bore; 4. a first transition arc; 5. a first torque shoulder; 6. a male connector; 7. an external thread; 8. a transition bevel; 9. a second transition arc; 10. a second torque shoulder; 11. an inner wall bevel; θ, torque shoulder angle.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

Fig. 1 is an axial cross-sectional view of the joint of the present invention. The taper pipe threaded joint is composed of a female joint 1 and a male joint 6, wherein the specification of the male joint 6 is 139.7 mm by 9.17mm, and the specification of the female joint 1 is 154 mm by 14 mm. An internal thread 2, a cylindrical hole 3, a transition circular arc I4 and a torque shoulder I5 are sequentially processed on the inner wall of the female joint 1; the outer wall of the male connector 6 is sequentially processed with an external thread 7, a transition inclined plane 8, a transition circular arc II 9, a torque shoulder II 10 and an inner wall inclined plane 11. When in use, the internal thread 2 and the external thread 7 are mutually meshed to provide enough connection strength for the joint; the first torque shoulder 5 and the second torque shoulder 10 are in extrusion contact to form a sealing structure, so that gas leakage is prevented, the joint has a gas sealing effect, and the over-torsion resistance is enhanced; the first transition arc 4 and the second transition arc 9 provide free release space for stress deformation under complex working conditions, and can effectively protect the sealing structure and the torque shoulder.

Fig. 2 is the utility model discloses connect regional A enlargements of moment of torsion circular bead, including internal thread 2, cylinder hole 3, transition circular arc 4, moment of torsion circular bead 5, external screw thread 7, transition inclined plane 8, two 9, two 10, inner wall inclined planes 11, moment of torsion circular bead angles theta of transition circular arc. Wherein the length of the cylindrical hole 3 is 10mm, the radian of the first transition arc 4 is 1.6mm, the radian of the second transition arc 9 is 0.6mm, and the torque shoulder angle theta is 5 degrees. The diameter ratio of cylinder hole 3 is 0.5mm bigger than the root diameter of the adjacent internal thread 2, and the external thread produces interference damage when avoiding turning round excessively. After the connector is screwed down, the first torque shoulder 5 and the second torque shoulder 10 are in axial interference fit to form contact pressure to play a sealing role, and simultaneously share the screwing-up torque of the threads, so that the pipe end shrinkage during large torque is avoided, and the torque resistance of the connector is improved.

Claims

1. A simple anti-over-torsion air-tight seal threaded joint comprises a female joint (1) and a male joint (6), wherein an internal thread (2), a cylindrical hole (3), a transition circular arc I (4) and a torque shoulder I (5) are sequentially processed on the inner wall of the female joint (1); the outer wall of the male connector (6) is sequentially processed with an external thread (7), a transition inclined plane (8), a transition circular arc II (9), a torque shoulder II (10) and an inner wall inclined plane (11); the method is characterized in that: the root of a first torque shoulder (5) of the female joint (1) is designed with a first transition arc (4); the top of a second torque shoulder (10) of the male joint (6) is designed with a second transition arc (9); the first torque shoulder (5) and the second torque shoulder (10) are negative-angle torque shoulders.

2. The simple anti-over-torque gas-tight seal threaded joint as claimed in claim 1, wherein the pitch diameter of the internal thread (2) is 0.1 ~ 0.3.3 mm larger than the pitch diameter of the external thread (7).

3. The simple anti-over-torque gas-tight seal threaded joint according to claim 1, wherein: the inclination angle theta of the first torque shoulder (5) and the second torque shoulder (10) is-3 degrees to-8 degrees.

4. The simple anti-over-torque gas-tight seal threaded joint according to claim 1, wherein: the radius of the first transition arc (4) is 1.4-1.8 mm, and the radius of the second transition arc (9) is 0.4-0.8 mm.

5. The simple anti-over-torque gas-tight seal threaded joint as claimed in claim 1, wherein the length of the cylindrical hole (3) of the female joint (1) is 8 ~ 12mm, and the diameter of the cylindrical hole (3) is 0.4-0.7 mm larger than the diameter of the thread tooth bottom at the position.