WO2017177544A1

WO2017177544A1 - Grid-lined, pre-dimpled, double-layer, mechanically lined pipe, and lining pipe thereof

Info

Publication number: WO2017177544A1
Application number: PCT/CN2016/086500
Authority: WO
Inventors: 王云孝; 商伟军; 张镇雄
Original assignee: 王云孝
Priority date: 2016-04-13
Filing date: 2016-06-21
Publication date: 2017-10-19
Also published as: CN107289204A

Abstract

A grid-lined, pre-dimpled, double-layer, mechanically lined pipe, and an outer pipe and lining pipe thereof. The outer wall of the lining pipe is closely attached on the inner wall of the outer pipe; there is a plurality of non-attached plastically deformed areas between the outer wall of the lining pipe and the inner wall of the outer pipe; the plastically deformed areas are on the surface of the lining pipe and is downwardly recessed towards the center of the lining pipe; the positions of the plastically deformed areas are the positions of critical flaws of the lining pipe; the critical flaws are periodically and artificially set flaws. According to the grid-lined, pre-dimpled, double-layer, mechanically lined pipe, and the outer pipe and lining pipe thereof, the contact structure between the inner pipe and the outer pipe is changed by artificially providing multiple periodically and regularly arranged critical flaws, such that irregular flaws randomly generated on the liner are avoided.

Description

Array type pre-deformation double-layer mechanical tube and lining tube thereof

Technical field

The present invention relates to a double pipe and a lining pipe thereof, and more particularly to an array type pre-deformation double-layer mechanical pipe and a lining pipe thereof.

Background technique

The anti-corrosion pipe used in the petroleum industry, the outer pipe and the lining pipe are all metal materials. This is a bimetallic lining tube, English is MECHANICALLY LINED PIPE, abbreviated as MLP, this patent is translated into mechanical tube. The mechanical tube is a thin anti-corrosion alloy lining layer inside the carrier tube to be composited into a bimetallic tube. There is a technical bottleneck in the metal lining of the traditional mechanical pipe, that is, when the mechanical pipe is subjected to a bending load, the metal lining layer is easily detached from the outer pipe.

A two-material layer mechanical composite product required for various reasons (such as the above-mentioned corrosion protection), wherein the thinner layer inside is a lining layer. The outer and inner layers are integrally formed by mechanical compounding. Mechanical compounding is a combination of physical aspects (such as by pressure) and no atomic bonding at the metallographic level. This two-material layer mechanical composite product is suitable for a wide variety of structures, including boxes of any shape, such as a box, cylinder or sphere.

The inner and outer layers of the two-material layer mechanical composite product need to adopt different materials, so that the inner and outer layers each play their respective roles. For example, in the anti-corrosion pipeline, the outer tube is a high-strength steel to carry the load, and the inner liner is an alloy. Antiseptic effect. The inner and outer layers of the two-material layer mechanical composite product are usually made of different materials. For example, as mentioned above, the outer pipe material is a common high-strength steel which is relatively cheap, and the inner metal lining layer is an expensive alloy layer. Cost savings are achieved by designing a thinner metal lining layer.

So far, the lining layer is a pure round tube, which adopts the same shape as the outer tube. The starting point is that the two tubes of the two-material layer tube work as much as possible to become a tube, and if deformed, they are co-deformed.

In order to achieve this goal, in the manufacture of two-material layer mechanical composite products, the current process usually requires pre-grinding of the inner and outer tube joint surfaces in advance, ensuring that no gap is left between the inner and outer tubes, thereby making the inner and outer tubes integral.

But this pure tube lining is actually difficult to achieve without leaving any gaps. Regardless of the high processing accuracy, the inner and outer material layers are virtually impossible to process into a purely cylindrical shape, that is, there are "geometric defects" between the inner and outer tubes, and defects often appear in different places. This slight difference leads to the lining layer of the traditional two-material layer mechanical composite product being bent, such as when the pipeline in the petroleum industry is installed through the reel, the lining layer (inner tube) is detached from the outer tube, and the detachment is This is the location where the "defect" is located.

This traditional mechanical tube technology has serious process defects, because the finish is difficult to guarantee, and only theoretically possible. As long as there are minor defects on the outer surface of the inner tube or the inner surface of the outer tube, the mechanical tube will inevitably become unstable.

In the face of instability and shedding, the popular solution is to increase the thickness of the lining layer and increase the wall thickness of the pure tube lining layer in accordance with the need to resist bending instability. However, the intention of the two-material layer mechanical composite product is to avoid the cost.

Summary of the invention

In view of the problem that the "defect" of the double tube existing in the prior art is highly prone to fall off, it is an object of the present invention to provide an array type pre-deformed double-layer mechanical tube and a lining tube thereof.

To achieve the above object, the present invention adopts the following technical solutions:

An array type pre-deformed double-layer mechanical tube includes an outer tube and a lining tube. The outer wall of the lining tube is tight The inner wall of the outer tube is attached, and there are a plurality of non-adhesive plastic deformations between the outer wall of the lining tube and the inner wall of the outer tube.

According to an embodiment of the invention, the plastic deformation is disposed on the surface of the liner tube and is recessed downward toward the center of the liner tube. The plastic deformation position is the critical defect position of the liner tube, and the critical defect is the artificial defect periodically set.

According to an embodiment of the invention, the critical defect location is: W _o (x, θ) = W _ocr · f _ox (x) · f _o θ (θ), wherein: W _o is a critical defect, is an axial x coordinate And a function of the circumferential θ coordinate, where f _ox (x) is an axial function,

L is the length of the pipe, m _o is the number of axial half sine waves, a is the exponent; f _oθ (θ) is the circumferential function,

n _o is the number of circumferential half sine waves, b is the index; W _ocr is the critical defect value, when a = b = 2, the critical defect value is

K1, k2 and k3 are constants determined according to working conditions, R _L is the lining radius, and L is the length of the pipe.

According to an embodiment of the invention, the outer tube and the liner tube are both metallic materials.

According to an embodiment of the invention, the locations of the plastic deformation are a regularly arranged array shape.

According to an embodiment of the invention, each of the plastic deformation portions is provided with a reinforcing rib.

An array type pre-deformed lining pipe, the surface of the lining pipe has a plurality of plastic deformations, the plastic deformation is disposed on the surface of the lining pipe, and is recessed downward toward the center of the lining pipe, and the position of plastic deformation is the critical defect position of the lining pipe, A critical defect is an artificial defect that is periodically set.

According to an embodiment of the invention, the critical defect location is: W _o (x, θ) = W _ocr · f _ox (x) · f _oθ (θ), wherein: W _o is a critical defect, is an axial x coordinate and a function of the circumferential θ coordinate, where f _ox (x) is an axial function,

According to an embodiment of the invention, the strength of the outer tube is greater than the strength of the liner tube.

In the above technical solution, the array type pre-deformation double-layer mechanical tube and the lining tube thereof of the present invention change the contact structure of the inner tube and the outer tube by artificially setting a plurality of periodic and regularly arranged critical defects, thereby avoiding Irregular defects randomly generated by the lining layer.

DRAWINGS

Figure 1 is a schematic view showing the structure of a conventional backing layer;

Figure 2 is a schematic view showing the structure of the lining layer of the present invention;

Figure 3 is a schematic view of a pre-deformed axial array;

Figure 4 is a schematic view of a pre-deformed circumferential array;

Figure 5 is a flow chart of the prefabrication method of the array type pre-deformed lining of the present invention;

6A to 6C are schematic views of the reinforcing ribs.

detailed description

The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

The invention discloses a special type of new lining layer, a double tube applying the lining layer, and a manufacturing method of the double tube (prefabrication method and reinforced rib thereof). The core of the invention is a lining layer, the full name of which is an array type pre-deformed lining layer, the English name is Grid-Lined Pre-Dimpled Liner, abbreviated as GPL, which is a lining layer pre-added with array deformation. For example, a non-pure cylindrical lining layer which is deformed by minute irregularities arranged in a certain order in the axial direction and the circumferential direction is preliminarily processed.

As shown in Fig. 1 and Fig. 2, it is a schematic diagram of a circular tube lining represented by a grid. The outer tube is not shown, wherein Fig. 1 is a pure circular tube, and Fig. 2 is artificially applied to the surface of a pure circular tube. Treatment results in a pre-strained liner.

The theoretical basis of the array pre-deformed lining is the critical defect.

In theory, a pure tube lining can withstand an infinite bending load while maintaining the state of the tube. But a pure round tube is impossible, because no matter what kind of processing technology, it will inevitably leave geometric defects. The size of the geometric defect determines the load carrying capacity of the lining. When the actual geometric defect is less than the critical defect, the lining has an infinitely high bending resistance; and when the geometric defect is greater than the critical defect, the lining will gradually lose the bending resistance as the bending load increases.

The formation of a pre-deformed lining layer is defined as a lining layer to which a critical defect is applied.

The purpose of the pre-deformation applied by the pre-deformed lining is to avoid the random irregularities of the lining layer by artificially applying critical defects. Critical defect is an optimization of a lining tube Choice, its resistance to bending is greatest.

Therefore, as shown in FIG. 2, the array type pre-deformation double-layer mechanical tube of the present invention comprises an outer tube 1 and a lining tube 2. The outer wall of the lining tube 2 abuts against the inner wall of the outer tube 1, and there are a plurality of non-adhesive plastic deformations between the outer wall of the lining tube 2 and the inner wall of the outer tube 1. The plastic deformation is provided on the surface of the lining tube 2, and is recessed downward toward the center of the lining tube 2, the position of plastic deformation is the critical defect 3 position of the lining tube 2, and the critical defect 3 is an artificial defect periodically set.

Further, as shown in FIG. 2, the positions of the plastic deformation are regularly arranged array shapes, and the reinforcing ribs 4 may be provided at each plastic deformation. Further, the outer tube 1 and the lining tube 2 are both made of a metal material, and the strength of the outer tube 1 is greater than the strength of the lining tube 2.

Specifically, the critical defect 3 is distributed over the surface of the liner, and the size of the defect varies with the axial and circumferential directions, namely:

W _o (x, θ)=W _ocr ·f _ox (x)·f _oθ (θ) (1)

In formula (1):

W _o is a critical defect and is a function of the axial x-coordinate and the circumferential θ coordinate.

f _ox (x) is an axial function

f _oθ (θ) is a circumferential function

W _ocr is the critical defect value

The axial and circumferential functions depend on the specific lining conditions. An approximate calculation is to simplify the axial function to:

In the formula (2), L is the length of the pipe, m _o is the number of axial half sine waves, and a is an index.

At the same time, the circumferential function can be simplified to:

In the formula (3), n _o is the number of circumferential half sine waves, and b is an index.

Once the axial and circumferential functions are determined, the critical defect value can be obtained from the energy method. When a=b=2, the critical defect value can be expressed as:

In the formula (4), k1, k2 and k3 are constants determined according to working conditions, R _L is the lining radius, and L is the pipe length.

The above method of calculating critical defects can also be extended to the following algorithm:

The number of array type pre-deformations is usually expressed by m ₀ , n ₀ .

As shown in Fig. 3, m ₀ = 8, and in Fig. 4, n ₀ = 16. The specific values of m ₀ and n ₀ depend on the parameters of the material, diameter and wall thickness of the inner and

outer tubes

1 and 2, and need to be determined by analysis and calculation according to actual working conditions.

Pre-deformation can theoretically use an expanded sine wave such as

with

To express.

Each pre-deformation is very small and is a kind of micro-concave and convex in the radial direction of the lining tube 2 (can be compared to the dimple or sputum commonly found in the agenda life), so as not to affect the mechanical function of the pipeline. The size of the pre-deformation is expressed in W _ocr :

In the formula (5): μ ₂ and μ ₃ are:

In equation (6):

α _L2 =α _Lθ +να _Lx (9)

α _P2 =α _Pθ +να _Px (10)

C _{woδw_b} =π (14)

In the formulas (6) to (14), t _L and t _P are the wall thicknesses of the lining tube 2 and the outer tube 1, respectively, and R _Li , R _Lo and R _L are the inner radius, the outer radius and the center line of the lining tube 2, respectively. Radius, R _PO is the outer diameter of the outer tube 1, R _r and β can be taken as 1000R _L and 0.001, respectively, α _Lx , α _Lθ , α _PX and α _Pθ are the axial and circumferential _sides of the lining tube 2 and the outer tube 1 respectively The coefficient of thermal expansion, ν is the Poisson's ratio.

Taking a section of a 0.3m long submarine pipeline as an example, it is subjected to high temperature and high pressure, and its parameters are given in Tables 1 and 2:

Table 1: Pipeline parameters

Table 2: Thermal expansion coefficient

The pre-deformation under this condition is regularly arranged in the circumferential direction and the axial direction, as shown in Table 3:

Table 3: Pre-deformed array arrangement

m_o m _o	n_o n _o	w_ocr(mm)w _ocr (mm)
77	2525	0.10.1

For the double tube structure of the outer tube 1 and the lining tube 2 of the present invention, there are two different ways in the manufacturing process. The first is to make the outer tube 1 and the lining tube 2 separately, and the other method is to adopt the array type pre-deformation lining prefabrication method, as shown in Fig. 5, mainly including the following steps:

S1: According to the shape and size of the outer tube 1, a preform of the lining tube 2 matched with the outer tube 1 is produced.

S2: Calculating a plurality of pre-deformation positions on the outer surface of the preform, the pre-deformation position is the critical defect 3 position of the preform, and the critical defect 3 is an artificial defect periodically set.

S3: Inserting the preform into the outer tube 1, specifically, can be divided into the following two sub-steps:

S3.1: The rib 4 is set at the calculated pre-deformation position.

S3.2: The preform with the rib 4 is inserted into the outer tube 1.

S4: An internal pressure is applied in the tube so that the preform is integrated with the outer tube 1, and the preform is slightly plastically deformed at the periphery of the pre-deformed position.

In the above steps, the method of calculating the critical defect 3 is as described above, and will not be described again here.

In addition, the reinforcing ribs 4 are used in both the structure and the prefabrication method of the double tube, as shown in Figs. 6A-6C, the reinforcing ribs 4 are regular shaped members arranged in a regular arrangement on the outer surface of the lining preform, for example An axial or circumferential array arrangement is formed. The material of the reinforcing rib 4 is high-strength steel whose strength is greater than or equal to the material of the outer tube 1, and its shape is a cubic sheet or a spherical particle.

The ribs 4 can have various forms, and may be components that are discretely distributed according to a certain rule, or components that are continuously and regularly distributed.

The ribs 4 shown in Figs. 6A and 6B are regularly discretely distributed, the rib 4 shown in Fig. 6A is a cube, and the rib 4 shown in Fig. 6B is a "ten" shape, which may also be a "one" shape. Or "|" glyph. The rib 4 shown in Fig. 6C is continuously distributed, which is equivalent to the cross of Fig. 6B. Each of the sides of the shape is elongated, and the adjacent reinforcing ribs 4 are connected to each other to form a network-like reinforcing rib 4, thereby achieving a regular arrangement of continuous distribution.

In summary, when the outer surface of the inner tube of the mechanical tube or the inner surface of the outer tube is less than a critical defect, the mechanical tube will never fall off in theory. Mechanical pipeline critical defects are very small, in the range of a few hundred filaments. According to the critical defect theory of the present invention, conventional mechanical tubes are not technically capable of controlling manufacturing accuracy within the allowable manufacturing cost to meet critical defect requirements.

Therefore, instead of improving the process to ensure the smoothness of the surface to prevent the lining layer from destabilizing, it is better to introduce the defect according to the critical defect, so that the inner lining layer can be slightly destabilized and detached everywhere, thereby preventing local instability and falling off.

The thickness of the liner required for conventional mechanical tubes increases with increasing bending requirements, while the thickness of the liner of the double tube of the present invention requires only a thickness of 1 mm, or the minimum thickness required for the processing.

It should be understood by those skilled in the art that the above embodiments are only intended to illustrate the invention, and are not intended to limit the invention, as long as it is within the spirit of the invention, Variations and modifications are intended to fall within the scope of the appended claims.

Claims

An array type pre-deformation double-layer mechanical tube, comprising:

Outer tube and lining tube;

The outer wall of the lining tube abuts against the inner wall of the outer tube, and the outer wall of the lining tube and the inner wall of the outer tube have a plurality of non-adhesive plastic deformations.
The array type pre-deformation double-layer mechanical tube according to claim 1, wherein the plastic deformation is provided on a surface of the lining tube and is recessed toward a center of the lining tube, and the position of the plastic deformation is a lining tube. The critical defect location, which is a manually set artificial defect.
The array type pre-deformation double-layer mechanical tube according to claim 2, wherein the critical defect position is:

W o (x, θ) = W ocr · f ox (x) · f oθ (θ), where:

W o is a critical defect and is a function of the axial x coordinate and the circumferential θ coordinate, where

f ox (x) is an axial function,
L is the length of the pipe, m o is the number of axial half sine waves, and a is the index;

f oθ (θ) is a circumferential function,
n o is the number of circumferential half sine waves, and b is the index;

W ocr is the critical defect value. When a=b=2, the critical defect value is

K1, k2 and k3 are constants determined according to working conditions, R L is the lining radius, and L is the length of the pipe.
The array type pre-deformation double-layer mechanical tube according to claim 1, wherein the outer tube and the lining tube are both made of a metal material.
The array type pre-deformation double-layer mechanical tube according to claim 1, wherein the position of the plastic deformation is a regularly arranged array shape.
The array type pre-deformation double-layer mechanical tube according to claim 5, wherein each of the plastic deformation portions is provided with a reinforcing rib.
An array type pre-deformed lining pipe, characterized in that the surface of the lining pipe has a plurality of plastic deformations, the plastic deformation is disposed on the surface of the lining pipe, and is recessed downward toward the center of the lining pipe, the plastic deformation The location is the critical defect location of the liner tube, which is a manually placed artificial defect.
The array type pre-deformed liner tube according to claim 7, wherein said critical defect position is:

W o (x, θ) = W ocr · f ox (x) · f oθ (θ), where:

W o is a critical defect and is a function of the axial x coordinate and the circumferential θ coordinate, where

f ox (x) is an axial function,
L is the length of the pipe, m o is the number of axial half sine waves, and a is the index;

f oθ (θ) is a circumferential function,
n o is the number of circumferential half sine waves, and b is the index;

W ocr is the critical defect value. When a=b=2, the critical defect value is

K1, k2 and k3 are constants determined according to working conditions, R L is the lining radius, and L is the length of the pipe.
The array type pre-deformed liner tube according to claim 7, wherein the position of the plastic deformation is a regularly arranged array shape.
The array type pre-deformed liner tube according to claim 7, wherein the strength of the outer tube is greater than the strength of the liner tube.