Pipeline joint

Abstract

The invention belongs to the technical field of pipeline transportation, and particularly relates to a pipeline joint. The pipeline joint comprises a second pipeline and a first pipeline communicated to the pipe wall of the second pipeline, an arc-shaped piece is arranged in the connecting position of the second pipeline and the first pipeline, and fluid flows to the second pipeline from the first pipeline. According to the invention, erosion corrosion can be greatly reduced, the use safety and reliability of the sewage gathering and transportation pipeline are improved, and the maintenance and use cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipeline transportation, and specifically, relates to a pipeline joint. Background Art

[0002] In the gathering and transportation of drilling and production sewage, in addition to inorganic salt ions exacerbating the corrosion of gathering and transportation pipelines, the high-speed relative movement between the inner wall surface of metal pipelines and corrosive fluids will also cause premature corrosion perforation in local areas of metal pipelines, namely erosion-corrosion.

[0003] Erosion-corrosion damage is the main form of damage to the oil drilling and production sewage gathering and transportation system. The corrosion of sewage gathering and transportation pipelines not only seriously affects production efficiency but also causes huge economic losses. According to the different media, erosion-corrosion can be divided into single-phase flow erosion-corrosion, two-phase flow erosion-corrosion, and multiphase flow erosion-corrosion. Since drilling sewage often contains different particles such as solid particles, liquid droplets, and bubbles, the solid particles contained in the multiphase flow during the sewage gathering and transportation process impact the surface of the carrier material at a certain speed, generating a mechanical effect. At the same time, the inorganic salt ions in the sewage chemically react with the inner wall surface of the pipeline. The corrosion damage under the combined action of the mechanical effect and the chemical effect is called erosion-corrosion. The erosion-corrosion of metal pipelines is affected by various factors, such as: the concentration, shape, particle size, and impact angle of particles in the medium; the velocity, flow pattern, and characteristics of the fluid; the pipeline material and gathering and transportation conditions, etc. The parts of the pipeline with the highest incidence of erosion-corrosion damage are elbows, tees, and reducers.

[0004] Taking the tee joint as an example, sewage containing a large amount of ions and impurities is lifted by a lift pump and flows into the pipeline, and a 90° bend occurs at the joint weld. Due to the influence of the pipeline pressure, the flow velocity at different positions in the pipeline changes. The sewage erodes the inner side of the inlet, and at the same time, due to the internal stress during the joint welding process, it is very sensitive to corrosion. The combined action of various factors exacerbates the erosion-corrosion at the weld. The lower part of the branch pipe of the tee joint bears the direct high-speed erosion of the sewage and is prone to erosion-perforation corrosion. After the sewage directly erodes the lower part of the branch pipe, it carries impurities, bubbles, etc. and rebounds to erode the bend, exacerbating the erosion-corrosion near the weld.

[0005] The frequent corrosion failure of the sewage gathering and transportation pipeline joints not only increases the maintenance and replacement costs of the gathering and transportation pipelines, but also the leakage of sewage brings a huge environmental pollution risk. Summary of the Invention

[0006] Aiming at the above-mentioned technical problems, the present invention aims to propose a pipeline joint, which can greatly reduce erosion-corrosion, improve the use safety and reliability of the sewage gathering and transportation pipeline, and reduce the maintenance and use costs.

[0007] According to the present invention, a pipe joint is provided, comprising: a second pipe and a first pipe connected to the pipe wall of the second pipe. An arc-shaped member is disposed inside the connection between the second pipe and the first pipe, and fluid flows from the first pipe to the second pipe.

[0008] In a preferred embodiment, the radius of curvature of the arc-shaped member is 0.2 to 0.5 times the inner diameter of the first pipe.

[0009] In a preferred embodiment, the central axis of the first pipe is perpendicular to the central axis of the second pipe.

[0010] In a preferred embodiment, a flow guiding gasket is fixedly disposed on the inner wall of the second pipe. The flow guiding gasket is located on the extension line of the central axis of the first pipe, and the flow guiding gasket is configured to be higher in the middle and lower on both sides.

[0011] In a preferred embodiment, the flow guiding gasket is configured to be a symmetric structure that is higher in the middle and lower on both sides.

[0012] In a preferred embodiment, the highest point in the middle of the flow guiding gasket is located on the extension line of the central axis of the first pipe.

[0013] In a preferred embodiment, the length of the flow guiding gasket is 1 to 3 times the inner diameter of the first pipe.

[0014] In a preferred embodiment, the length of the flow guiding gasket is 2 times the inner diameter of the first pipe.

[0015] In a preferred embodiment, the height of the flow guiding gasket is 0.01 to 0.1 times the inner diameter of the first pipe.

[0016] In a preferred embodiment, the height of the flow guiding gasket is 0.05 times the inner diameter of the first pipe.

[0017] Compared with the prior art, the advantages of the present application are as follows.

[0018] The present invention includes a first pipe and a second pipe that are at a certain angle to each other. The first pipe is connected to the pipe wall of the second pipe, and fluid flows from the first pipe to the second pipe. By arranging an arc-shaped member inside the joint of the first pipe and the second pipe, the Coanda effect of the fluid is utilized to spontaneously deflect the direction of the sewage in the pipe, which can greatly reduce the erosion and corrosion of the bottom of the second pipe by the sewage. By changing the radius of curvature of the arc-shaped member according to the working conditions, asymmetric diversion can be performed on the left and right parts of the second pipe, improving the use safety and reliability of the sewage collection pipeline and reducing the maintenance and use costs.

[0019] The present invention is also provided with a flow guiding gasket, which is located on one side of the second pipe relative to the first pipe and can resist the erosion of the fluid flowing out of the first pipe. The flow guiding gasket is provided with a wedge-shaped structure that is high in the middle and low on both sides, which can change the flow direction of the fluid and make the fluid flow along the left and right sides of the second pipe, preventing the fluid from rebounding to the connection between the first pipe and the second pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be described below with reference to the accompanying drawings.

[0021] Figure 1 shows a schematic diagram of an embodiment of a pipe joint according to the present invention;

[0022] Figure 2 shows a schematic diagram of the change in the flow direction of a fluid with viscosity when passing through a convex surface;

[0023] Figure 3 shows a schematic diagram of corrosion failure in the comparative example.

[0024] In the figure: 1, the first pipe; 2, the second pipe; 3, the arc-shaped member; 31, the first surface; 32, the second surface; 33, the arc surface; 4, the flow guiding gasket; 5, the convex surface; 10, the pipe joint.

[0025] In this application, all the drawings are schematic drawings, which are only used to illustrate the principle of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The present invention will be introduced below with reference to the accompanying drawings.

[0027] It should be noted that the directional terms or limiting words "up", "down", "left", "right", etc. used in this application are all with reference to the Figure 1 mentioned. They do not limit the absolute positions of the components involved, but can change according to specific situations.

[0028] Figure 1 shows the structure of the pipe joint 10 according to the present invention. As Figure 1 shown, the pipe joint 10 includes a first pipe 1 and a second pipe 2.

[0029] Among them, the inner diameter of the first pipe 1 is less than or equal to the inner diameter of the second pipe 2, and the lower end of the first pipe 1 is connected and arranged on the pipe wall of the second pipe 2. In Figure 1 , the fluid flows downward from the upper direction of the first pipe 1. After passing through the connection between the first pipe 1 and the second pipe 2, the fluid enters the second pipe 2 and finally disperses into two streams, flowing from the left and right sides of the second pipe 2 respectively.

[0030] An arc-shaped member 3 is provided inside the connection between the second pipe 2 and the first pipe 1. The first pipe 1 and the second pipe 2 are usually fixedly connected by welding. The arc-shaped member 3 is located inside the connection between the first pipe 1 and the second pipe 2, which can protect the weld seam between the first pipe 1 and the second pipe 2, prevent the fluid in the pipe from directly contacting the weld seam, and can also strengthen the weld strength between the first pipe 1 and the second pipe 2.

[0031] The cross-section of the arc-shaped member 3 includes a first surface 31, a second surface 32, and an arc surface 33. The first surface 31 is fixedly connected to the inner wall of the first pipe 1, the second surface 32 is fixedly connected to the inner wall of the second pipe 2, and the arc surface 33 is exposed to the fluid in the pipe. By providing the arc-shaped member 3, on the one hand, the weld strength between the first pipe 1 and the second pipe 2 is strengthened. On the other hand, the arc surface 33 of the arc-shaped member 3 can change the flow direction of the fluid flowing from the first pipe 1 to the second pipe 2.

[0032] When a viscous fluid passes through a convex surface 5 with a certain curvature, it has a tendency to adsorb to the convex surface 5. Due to the viscosity of the liquid, it drives the movement of the surrounding liquid, resulting in a centripetal force moving along the convex surface 5. This phenomenon is called the Coanda effect. As Figure 2 shown, when the fluid flows through the convex surface 5, after the surface curvature of the convex surface 5 satisfies certain conditions, the fluid will deviate from its original flow direction and instead flow along the convex surface 5. In the present invention, the arc-shaped member 3 can actively change the flow direction of the fluid. As Figure 1 shown by the arrow representing the fluid, it can avoid the direct erosion of the bottom of the second pipe 2 by the fluid, and can greatly reduce the erosion corrosion of the pipe joint 10. At the same time, after the flow direction of the fluid changes, it can further prevent the fluid from rebounding to the joint between the first pipe 1 and the second pipe 2 at the bottom of the second pipe 2.

[0033] The key to the fluid Coanda effect lies in the radius of curvature of the convex surface 5, that is, the radius of curvature of the arc surface 33 of the arc-shaped member 3 in the present invention. Therefore, the change in the flow direction of the fluid passing through the pipe joint 10 is largely affected by the radius of curvature of the arc surface 33. How to make full use of the fluid Coanda effect through structural design to reduce the erosion of the fluid on the pipe joint 10 is the key to improving erosion corrosion resistance.

[0034] In this embodiment, the central axis of the first pipe 1 is perpendicular to the central axis of the second pipe 2.

[0035] In this embodiment, the radius of curvature R of the arc-shaped member 3 (arc surface 33) is 0.2 to 0.5 times the inner diameter of the first pipe 1. The portions of the arc-shaped member 3 located on the left and right sides of the second pipe 2 can be set to have different radii of curvature. By appropriately adjusting the radii of curvature of the arc surfaces 33 of the two portions on the left and right sides of the second pipe 2 respectively, not only can the fluid in the pipe be actively redirected, but also the flow rates on the left and right sides of the second pipe 2 can be adjusted, which can be applied to the working conditions where the flow rates on the left and right sides of the second pipe 2 are asymmetric during actual use.

[0036] According to the present invention, in a preferred embodiment, a flow guiding gasket 4 is fixedly provided on the inner wall of the second pipe 2, and the flow guiding gasket 4 is located on the side opposite to the first pipe 1. Further, the flow guiding gasket 4 is located on the extension line of the central axis of the first pipe 1, and the flow guiding gasket 4 is configured to be higher in the middle and lower on both sides. After the fluid in the first pipe 1 flows downward and enters the second pipe 2, the fluid can flow to the flow guiding gasket 4, and the flow guiding gasket 4 can also change the flow direction of the fluid. By providing the flow guiding gasket 4, not only can the second pipe 2 be prevented from directly bearing the fluid erosion, but also the fluid can be quickly diverted, improving the durability.

[0037] In a specific embodiment, the flow guiding gasket 4 is configured to be a symmetric structure that is higher in the middle and lower on both sides. The highest point in the middle of the flow guiding gasket 4 is located on the extension line of the central axis of the first pipe 1, as Figure 1 shown, the pipe joint 10 is integrally configured to be a left-right symmetric structure.

[0038] According to the present invention, the length of the flow guiding gasket 4 is 1 to 3 times the inner diameter of the first pipe 1. The length of the flow guiding gasket 4 refers to the axial direction of the second pipe 2.

[0039] In a preferred embodiment, the length of the flow guiding gasket 4 is 2 times the inner diameter of the first pipe 1.

[0040] According to the present invention, the height of the flow guiding gasket 4 is 0.01 to 0.1 times the inner diameter of the first pipe 1. The height of the flow guiding gasket 4 refers to the axial direction of the first pipe 1.

[0041] In a preferred embodiment, the height of the flow guiding gasket 4 is 0.05 times the inner diameter of the first pipe 1.

[0042] In a specific embodiment, the material used for the pipe joint 10 is ordinary 20 steel, the inner diameter of the first pipe 1 is 300 mm, and the flow rate is 200 m 3 / h, and the flow velocity is about 0.8 m / s. In the laboratory working condition simulation, when the flow velocity is less than 0.2 m / s, the service life of the joint is basically the same as the design life of the pipeline. On the premise of meeting the above conditions, the critical condition is that the flow velocity in the middle of the transition part of the first pipe 1 is 0.2 m / s. As Figure 1As shown in the figure, the radius of curvature of the arcuate surface 33 of the arcuate member 3 on the left side of the second pipe 2 is 40 mm, and the radius of curvature of the arcuate surface 33 of the arcuate member 3 on the right side of the second pipe 2 is 60 mm. Under these conditions, the flow velocity in the left side of the second pipe 2 is approximately 0.4 m / s, and the flow velocity in the right side of the second pipe 2 is approximately 0.2 m / s. At the same time, the second pipe 2 is provided with a flow guiding gasket 4, and the height of the flow guiding gasket 4 is 20 mm, which can prevent the sewage from directly scouring and the bubbles and particles from rebounding to scour the upper pipe. Under the laboratory simulation working conditions, the service life of the pipe joint 10 can reach more than 3 years.

[0043] Comparative example:

[0044] The Cl- concentration in the drilling and production sewage is 1.14×105 mg / L. The corrosion of the pipeline during the gathering and transportation of the drilling and production sewage is very serious, especially at the part where the pipeline is connected to the outlet of the lifting pump. The pipe joint is an existing conventional T-shaped joint, that is, only the structure of the first pipe 1 and the second pipe 2 connected to each other is adopted.

[0045] In this comparative example, the material used for the pipe joint is 20 steel, the pipe diameter is 300 mm, and the flow velocity is 0.8 m / s. During the use process, the corrosion failure mainly occurs in three areas: the connection weld, the lower part of the second pipe 2, and the vicinity of the upper weld of the first pipe 1. The corrosion rate can reach 0.28 mm / a. Through the sampling analysis of the corrosion process and the pipeline after corrosion, it is found that the corrosion failure of the sewage gathering and transportation pipeline is mainly due to erosion-corrosion. The schematic diagram of the corrosion failure is as Figure 3 shown.

[0046] The service life of the pipe joint used in the comparative example is only about 4 months. Through the laboratory simulation working conditions, it can be seen that compared with the currently used conventional joints, the pipe joint 10 provided by the present invention can greatly increase the service life of the sewage pipe joint, reduce the production cost, and contribute to the safety of oil production and transportation.

[0047] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0048] In the present invention, unless otherwise clearly defined and limited, terms such as "install", "connect", "link", "fix", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0050] Finally, it should be noted that the above are only the preferred implementation schemes of the present invention and do not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the foregoing implementation schemes, for those skilled in the art, it is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A pipe joint, characterized in that, Including: A second pipe (2) and a first pipe (1) connected to the wall of the second pipe (2). An arc-shaped member (3) is provided inside the connection between the second pipe (2) and the first pipe (1). Fluid flows from the first pipe (1) to the second pipe (2).

2. The pipe joint according to claim 1, characterized in that, The radius of curvature of the arc-shaped member (3) is 0.2 to 0.5 times the inner diameter of the first pipe (1).

3. The pipe joint according to claim 2, characterized in that, The central axis of the first pipe (1) is perpendicular to the central axis of the second pipe (2).

4. The pipe joint according to any one of claims 1 to 3, characterized in that, A flow guiding gasket (4) is fixedly provided on the inner wall of the second pipe (2). The flow guiding gasket (4) is located on the extension line of the central axis of the first pipe (1), and the flow guiding gasket (4) is configured in a shape that is high in the middle and low on both sides.

5. The pipe joint according to claim 4, characterized in that, The flow guiding gasket (4) is configured in a symmetric structure that is high in the middle and low on both sides.

6. The pipe joint according to claim 5, characterized in that, The highest point in the middle of the flow guiding gasket (4) is located on the extension line of the central axis of the first pipe (1).

7. The pipe joint according to claim 6, characterized in that, The length of the flow guiding gasket (4) is 1 to 3 times the inner diameter of the first pipe (1).

8. The pipe joint according to claim 7, characterized in that, The length of the flow guiding gasket (4) is 2 times the inner diameter of the first pipe (1).

9. The pipe joint according to claim 6, characterized in that, The height of the flow guiding gasket (4) is 0.01 to 0.1 times the inner diameter of the first pipe (1).

10. The pipe joint according to claim 9, characterized in that, The height of the flow guiding gasket (4) is 0.05 times the inner diameter of the first pipe (1).

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