CN211875339U

CN211875339U - Threaded structure of threaded joint of PVC-lined steel pipe

Info

Publication number: CN211875339U
Application number: CN201922265812.XU
Authority: CN
Inventors: 杨力能; 罗华权; 李京川
Original assignee: China National Petroleum Corp; Pipeline Research Institute of CNPC
Current assignee: China National Petroleum Corp; CNPC Tubular Goods Research Institute; Pipeline Research Institute of CNPC
Priority date: 2019-12-16
Filing date: 2019-12-16
Publication date: 2020-11-06
Anticipated expiration: 2029-12-16

Abstract

The utility model discloses a inside lining PVC steel pipe screwed joint's helicitic texture, this helicitic texture comprises a plurality of thread tooth, and each thread tooth includes spigot surface and loading end, and wherein the contained angle scope between the perpendicular line of loading end and screw axis is 5 ~ 9, and the spigot surface is 35 ~ 50 with the contained angle scope of the perpendicular line of screw axis. The angle has good anti-thread gluing performance, and can be repeatedly used for screwing and unscrewing without damaging threads; the sealing performance is good and is superior to that of the API buttress thread; the button is easy to be buckled, can be buckled quickly, and is not easy to be buckled in a staggered manner. The utility model provides the high security that inside lining PVC steel pipe used at the defeated in-process of oil gas collection can connect the construction of installation fast, and the thread is anti to detain the performance and sealing performance good, and the required equipment of construction is simple, and economic cost is low, and the reliability is high, and the oil field and the enterprise of being convenient for use widely.

Description

Threaded structure of threaded joint of PVC-lined steel pipe

Technical Field

The utility model belongs to the technical field of tubular product helicitic texture design, a inside lining PVC steel pipe screwed joint's helicitic texture is related to.

Background

At present, oil field gathering and transportation pipelines mainly adopt common low-carbon alloy steel pipes for oil and gas transportation, and the pipelines are mostly connected in a welding mode. Because the conveying medium contains corrosivity, the low-carbon alloy steel pipe is used soon, the pipe body is seriously corroded, and the running of the pipeline has serious potential safety hazard. The pipelines are connected by welding, the welding construction procedure is complex, the quality of the welding seam is unstable, defects are easy to generate, and the maintenance and the replacement are inconvenient. Compared with the common low-carbon alloy steel pipe, the lining PVC steel pipe has the characteristic of good corrosion resistance.

The technical performance of the threaded connection is one of key points for ensuring the safe oil and gas transmission. The conventional round thread and buttress thread joints have the disadvantages of low connection strength and poor air tightness. With the harsh oil and gas transmission conditions, conventional standard API threads have not been able to meet the needs of engineering technology.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to solve among the prior art conventional inside lining PVC steel pipe screwed joint low in connection strength, the poor problem of air sealing performance, provide an inside lining PVC steel pipe screwed joint's helicitic texture.

In order to achieve the above purpose, the utility model adopts the following technical scheme to realize:

the utility model provides a inside lining PVC steel pipe screwed joint's helicitic texture, includes the thread tooth that a plurality of connects gradually, every thread tooth includes the loading end and rather than integrated into one piece's spigot surface, and the loading end is 5 ~ 9 with the contained angle alpha of the perpendicular line of thread tooth axis, and the spigot surface is 35 ~ 50 with the contained angle beta of the perpendicular line of thread tooth axis.

The utility model discloses a further improvement lies in:

preferably, the included angle alpha between the bearing surface and the perpendicular line of the axis of the thread tooth is 5-7 degrees.

Preferably, the angle β between the guide surface and the perpendicular to the thread tooth axis is 40 ° to 45 °.

Preferably, the angle β of the guide surface with respect to the perpendicular to the thread tooth axis is 44.5 °.

Preferably, the pitch P of the thread teeth is 2.54 mm.

Preferably, the pitch P of the thread teeth is 3.175 mm.

Preferably, the height of the thread teeth is 0.65 to 0.70 times of the thread pitch.

Compared with the prior art, the utility model discloses following beneficial effect has:

the utility model discloses a inside lining PVC steel pipe screwed joint's helicitic texture, the thread tooth that connects gradually including a plurality of, every thread tooth includes loading end and rather than integrated into one piece's spigot surface, and the loading end is 5 ~ 9 with the contained angle of the perpendicular line of thread tooth axis, and the spigot surface is 35 ~ 50 with the contained angle of the perpendicular line of thread tooth axis. The angle can effectively improve the overload resistance of the threaded connector, and can ensure that the thread is not disengaged when the threaded connector is used for multiple times and under a large axial load (F in figure 1)₁) Under the action of the elastic force, the thread bearing surface generates an oblique regular contact force (F in figure 1)₂) The risk of tripping is greatly reduced; the bearing surface at the angle ensures the stability of difficult thread release and connection of threads, ensures that the mechanical property of the threaded connection joint is similar to that of a pipe body, enhances the connection capacity of the threaded connection joint, and enhances the sealing property of a joint. The utility model provides the high security that inside lining PVC steel pipe used at the defeated in-process of oil gas collection can connect the construction of installation fast, and the thread is anti to detain the performance and sealing performance good, and the required equipment of construction is simple, and economic cost is low, and the reliability is high, and the oil field and the enterprise of being convenient for use widely.

Furthermore, the best value range of the alpha in the utility model is 5 degrees to 7 degrees, and the overload resistance of the threaded connector is strongest within the angle range.

Further, the utility model discloses well thread tooth's tooth height can be adjusted according to the pitch of difference, guarantees that the holistic intensity of screw is best.

Drawings

FIG. 1 is a schematic view of the thread structure of the threaded joint for PVC-lined steel pipes of the present invention;

wherein: 1-thread teeth; 2-carrying surface; 3-a guide surface; p-pitch; d-tooth height.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings:

example 1:

the utility model provides a inside lining PVC steel pipe screwed joint's helicitic texture, refers to figure 1, includes the thread tooth 1 that a plurality of connects gradually, and every thread tooth 1 includes bearing surface 2 and rather than integrated into one piece's spigot surface 3, and the bearing surface 2 is alpha with the contained angle of the perpendicular line of thread tooth 1 axis, and alpha's angle is 5. The angle between the guide surface 3 and the perpendicular to the axis of the thread tooth 1 is beta, which is in the range of 35 deg.. The pitch P of the thread tooth 1 is 2.54mm, and the tooth height D of the thread tooth 1 is 0.67 times the pitch P.

Example 2:

the utility model provides a inside lining PVC steel pipe screwed joint's helicitic texture, includes the thread tooth 1 that a plurality of connects gradually, and every thread tooth 1 includes bearing surface 2 and rather than integrated into one piece's spigot surface 3, and the contained angle of the perpendicular line of bearing surface 2 and 1 axis of thread tooth is alpha, and the angle of alpha is 7. The angle of the guide surface 3 to the perpendicular to the axis of the thread tooth 1 is beta, which is in the range of 50 deg.. The pitch P of the thread tooth 1 is 2.54mm, and the tooth height D of the thread tooth 1 is 0.65 times the pitch P.

Example 3:

the utility model provides a inside lining PVC steel pipe screwed joint's helicitic texture, includes the thread tooth 1 that a plurality of connects gradually, and every thread tooth 1 includes bearing surface 2 and rather than integrated into one piece's spigot surface 3, and the contained angle of the perpendicular line of bearing surface 2 and 1 axis of thread tooth is alpha, and alpha's angle is 9. The angle of the guide surface 3 to the perpendicular to the axis of the thread tooth 1 is beta, which is in the range of 44.5 deg.. The pitch P of the thread tooth 1 is 2.54mm, and the tooth height D of the thread tooth 1 is 0.7 times the pitch P.

The working principle of the utility model is as follows:

referring to fig. 1, the utility model discloses a helicitic texture includes the thread tooth 1 that a plurality of connects gradually, and each thread tooth 1 is the helicitic texture between a pitch P, and adjacent thread tooth 1 end to end connects, as shown in fig. 1, and the junction rounding between the adjacent thread tooth 1 is handled. Each thread tooth 1 comprises a guide surface 3 and a bearing surface 2 which are integrally formed, the bearing surface 2 and a perpendicular line of the axis of the thread tooth 1 form an included angle alpha, the alpha ranges from 5 degrees to 9 degrees, and preferably, the alpha ranges from 5 degrees to 7 degrees. The axis of the thread tooth 1 is the axis 1 of the thread structure. Since oil and gas technology pipelines are subjected to large internal pressures, the pressures are usually from a few MPa to a few tens of MPa. As a result, the threaded connection is subjected to large axial and circumferential loads. Under the action of a larger load, whether the thread teeth can be effectively meshed or not is not disengaged, and the angle of the bearing surface is related. The utility model discloses a screw thread profile of tooth, its loading end 2 is 5 ~ 9 with the angle 1 of the perpendicular line of 1 axis of thread tooth, can effectively improve the anti overloaded ability of threaded connection head to enable the screw thread not to drop off when repetitious usage, under the effect of big axial load, the screw thread loading end can produce the oblique regular contact force, very big reduction the risk of dropout. The bearing surface with a small angle ensures the stability of difficult thread release and connection of the thread, and leads the mechanical property of the threaded connection joint to be similar to that of the pipe body.

The angle between the guide surface 3 and the perpendicular to the axis of the thread tooth 1 is beta, which is in the range of 35-50 degrees, preferably in the range of 44.5 degrees. The effect of spigot surface 3 is that the screw thread plays the effect of direction at the screw in-process, and whether the spigot surface 3 directly influences the screw in with the contained angle size of screw axis whether convenient and can take place the condition such as dropout at the screw in-process, if this contained angle is too big, can influence screwed joint's joint strength, reduces airtight performance, if this contained angle undersize, will lead to the difficulty of detaining again. Through practical use, the angle can ensure the stability of screwing in the threads and is not easy to be disengaged. The pitch P of thread tooth 1 is 2.54mm or 3.175mm, and the tooth height D of thread tooth 1 highly is 0.65 ~ 0.70 times of screw thread P, and tooth height D is a key data, and reasonable tooth height has very important influence to the holistic intensity of screw thread, the utility model discloses in set up tooth height D to 0.65 ~ 0.70 times of screw thread P and can guarantee that the holistic intensity of screw thread reaches the optimum value.

The connection of inside lining PVC steel pipe adopts threaded connection rather than welded connection mode because if the inside lining PVC steel pipe that adopts welded connection, when the welded steel pipe, can produce the high temperature of thousand degrees, can melt and burn the PVC inside lining of welding part this moment. Once the two pipes are welded, the damaged lining at the welding position of the pipeline cannot be repaired after the pipe diameter of the gathering and transportation pipeline is smaller. After the pipeline normally runs, the welded part is easier to be a part where the pipeline generates corrosion defects and even punctures because the welding part does not have the corrosion protection effect of the PVC lining. And inside lining PVC steel pipe adopts threaded connection, does not have welded influence during the pipe connection, and the PVC inside lining of pipeline internal connection department just can not suffer destruction, therefore has guaranteed the integrality of pipeline inside lining PVC, has also guaranteed the reliability of pipe connection department consequently. Therefore, the PVC-lined steel pipes need to be connected by screw threads instead of welding. And the threaded connection is convenient for pipeline construction, and the connection is convenient to replace if a problem occurs, so that the threaded connection has wide application prospect in the oil field ground gathering pipeline.

The above contents are only for explaining the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby, and any modification made on the basis of the technical solution according to the technical idea of the present invention all fall within the protection scope of the claims of the present invention.

Claims

1. The thread structure of the PVC-lined steel pipe threaded joint is characterized by comprising a plurality of thread teeth (1) which are sequentially connected, wherein the tooth height (D) of each thread tooth (1) is 0.65-0.70 times of the thread pitch (P); each thread tooth (1) comprises a bearing surface (2) and a guide surface (3) which is integrally formed with the bearing surface, the included angle alpha between the bearing surface (2) and the perpendicular line of the axis of the thread tooth (1) is 5-9 degrees, and the included angle beta between the guide surface (3) and the perpendicular line of the axis of the thread tooth (1) is 35-50 degrees.

2. The thread structure of a threaded joint for PVC steel pipes as claimed in claim 1, wherein the angle α between the bearing surface (2) and the perpendicular to the axis of the thread tooth (1) is 5 ° to 7 °.

3. The thread structure of a threaded joint for PVC steel pipes lined according to claim 1, wherein the angle β between the guiding surface (3) and the perpendicular to the axis of the thread tooth (1) is 40 ° to 45 °.

4. A threaded joint for PVC steel pipes as claimed in claim 1, characterized in that the angle β between the guiding surface (3) and the perpendicular to the axis of the thread tooth (1) is 44.5 °.

5. The thread structure of a threaded joint for PVC steel pipes lined according to claim 1, wherein the pitch (P) of the thread tooth (1) is 2.54 mm.

6. The thread structure of a threaded joint for PVC steel pipes lined according to claim 1, wherein the pitch (P) of the thread tooth (1) is 3.175 mm.