Lining non-metal composite steel pipe hot melting joint and machining method thereof

Abstract

The invention belongs to the field of petroleum pipes, and particularly discloses a lining non-metal composite steel pipe hot melting connector and a machining method thereof.The lining non-metal composite steel pipe hot melting connector comprises a base pipe, a lining layer, flanges, bolts, electric heating wires and nuts; according to the method, the lining layer is installed in the base pipe with the flanges welded to the two ends, the lining layer at the ends of the base pipe is heated and flanged, and the flanged structures are attached to the flanges; the electric heating wire is pressed into the flanging structure in the flanging process; the two flanges are aligned and connected through bolts and nuts, and certain pre-tightening force is applied to the flanges; after connection is completed, the electric heating wires are heated, the non-metal lining layers at the joints are connected through hot melting, and after the flanging structures are welded and cooled, the bolts and the nuts are adjusted again, so that the two flanges are connected in a fastened mode; the integrity and the sealing performance of the lining material at the joint are guaranteed, a conveying medium in the pipe is completely isolated from the base pipe of the steel pipe, corrosion of the conveying medium to the base pipe is avoided, and meanwhile the connection strength of the joint is guaranteed through flange connection.

Description

Technical Field

[0001] The invention belongs to the field of petroleum pipes, and in particular relates to a lined non-metallic composite steel pipe hot-melt joint and a processing method thereof. Background Art

[0002] In order to solve the problems of corrosion, scaling, wax deposition, etc. in the gathering and transportation pipelines, lined non-metallic composite steel pipes are widely used as ground gathering and transportation pipelines in many oil fields. That is, non-metallic linings are installed on the inner surface of the steel base pipe to improve the corrosion resistance and anti-scaling properties of the steel pipe. Currently, the commonly used non-metallic lining materials mainly include plastic materials such as polyethylene and polypropylene, among which high-density polyethylene and ultra-high molecular weight polyethylene are widely used. Because of their good wear resistance, toughness, and resistance to acid, alkali and various salt corrosion, they are increasingly widely used in gathering and transportation pipelines.

[0003] For the lined non-metallic composite steel pipe gathering and transportation pipeline, the integrity and sealing of the lining layer have always been the key factors affecting pipeline corrosion and its service life. The connection joint is the key part of the pipeline medium leakage and pipeline corrosion. At present, the connection methods of lined non-metallic composite steel pipe mainly include welding, clamp connection, flange connection and other connection methods:

[0004] (1) For welded lined non-metallic composite steel pipes, internal anti-corrosion patching or UB liner technology can be used for internal anti-corrosion of the joints on site. However, since the diameter of the gathering and transportation pipelines is generally small, the internal anti-corrosion patching technology is difficult to construct, the cost is high, and the quality control is difficult. For the joints that use the inner wall UB liner for corrosion protection, it is difficult to inspect the bonding quality between the liner and the inner liner, and there is a risk of burning of the UB liner during the subsequent welding process. Therefore, the medium in the pipeline is easy to enter the interface between the base pipe and the inner liner from the poor bonding or the liner burnt part, causing corrosion of the base pipe.

[0005] (2) The clamp and flange connection commonly used at present is to apply the tightening force on the clamp and flange to the flange lining layer of the composite steel pipe end, so that the flange lining material and the sealing ring on both sides of the joint fit tightly to achieve the sealing effect. In actual operation, due to the influence of factors such as mechanical assembly errors and non-standard construction operations, the size of the tightening force is difficult to guarantee, and the sealing effect cannot be guaranteed. In addition, when the surface of the flange lining material or the sealing ring is damaged, these damaged parts are very likely to become channels for the internal transmission medium to leak. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a lined non-metallic composite steel pipe hot-melt joint and a processing method thereof to solve the problem of pipeline leakage and lining layer damage that easily occur when connecting existing lined non-metallic composite steel pipes, leading to base pipe corrosion.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a lined non-metallic composite steel pipe hot-melt joint, comprising:

[0009] A base pipe, an inner lining layer, a flange, bolts, a heating wire and nuts; the inner lining layer is arranged inside the base pipe and is arranged close to the inner wall of the base pipe; the two ends of the base pipe are respectively connected to a flange; the inner lining layer forms a flange structure at the end of the flange away from the base pipe, and the flange structure is arranged close to the end of the flange away from the base pipe; the two flanges are fastened and connected by bolts and nuts; and the heating wire is arranged in the flange structure.

[0010] Furthermore, the base pipe includes a first base pipe and a second base pipe, and both ends of the first base pipe and the second base pipe are connected to a flange respectively.

[0011] Furthermore, the lining layer forms a flange structure at the end of the flange at both ends of the first base pipe and the second base pipe away from the base pipe.

[0012] Furthermore, a plurality of bolt holes are evenly arranged on the same circumference of the flange, and the bolts penetrate the bolt holes.

[0013] Furthermore, one end of the bolt is connected to a nut.

[0014] Furthermore, a heating wire is arranged in the flange structure arranged on the first base tube or the second base tube.

[0015] Furthermore, heating wires are arranged in the flange structures arranged on the first base tube and the second base tube.

[0016] Furthermore, the heating wire is arranged around the flange structure, and a connecting terminal is respectively provided at both ends of the heating wire, and the two connecting terminals are connected to the electric fusion welding machine.

[0017] Furthermore, welds are provided at both ends of the base pipe, and the flange is welded to the base pipe through the welds.

[0018] In a second aspect, the present invention provides a method for processing a lined non-metallic composite steel pipe hot-melt joint, based on any one of the lined non-metallic composite steel pipe hot-melt joints described above, comprising:

[0019] Flanges are welded at both ends of the base pipe, and the inner lining layer is installed inside the base pipe. The length of the inner lining layer is greater than the length of the base pipe after the flange is welded. A certain length of the inner lining layer is reserved outside the end of the flange away from the base pipe. The reserved inner lining layer is heated and flanging, and the flanging structure is attached to the end of the flange away from the base pipe. During the flanging process, the electric heating wire is pressed into the flanging structure.

[0020] Align the two flanges and connect them with bolts and nuts. Apply a certain pre-tightening force to the flanges by adjusting the bolts and nuts. After the connection is completed, heat the electric heating wire so that the two flange structures are in a molten state, so that the two flange structures are melted and combined. After the flange structures are welded and cooled, adjust the bolts and nuts again to tighten the two flanges.

[0021] The present invention has at least the following beneficial effects:

[0022] 1. The present invention installs the lining layer inside the base pipe with flanges welded at both ends, heats the lining layer at the end of the base pipe and flanging it, and sets the flanging structure in contact with the flange; during the flanging process, press the electric heating wire into the flanging structure; align the two flanges and connect them through bolts and nuts, and apply a certain pre-tightening force to the flanges; after the connection is completed, heat the electric heating wire to connect the non-metallic lining layer at the joint through hot melting, and after the flanging structure is melted and cooled, adjust the bolts and nuts again to tighten the two flanges; ensure the integrity and sealing of the lining material at the joint, achieve complete isolation of the conveying medium in the pipe and the steel pipe base pipe, avoid corrosion of the base pipe, and at the same time ensure the connection strength of the joint by flange connection.

[0023] 2. The inner lining layer at the joint of the present invention is connected by hot melting, and no sealing gasket is required, which simplifies the on-site construction, improves the reliability of the joint connection, does not require on-site welding, is simple to operate, and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] Figure 2 It is a schematic diagram of the cross section of cc;

[0027] Figure numerals: 1, base pipe; A, first base pipe; B, second base pipe; 2, inner lining layer; 3, weld; 4, flange; 5, bolt; 6, flanging structure; 7, heating wire; 8, nut; 9, bolt hole. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0029] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0030] Example 1

[0031] like Figure 1-Figure 2 As shown, a lined non-metallic composite steel pipe hot-melt joint comprises:

[0032] Base pipe 1, inner lining layer 2, flange 4, bolt 5, electric heating wire 7 and nut 8; inner lining layer 2 is arranged inside base pipe 1, close to the inner wall of base pipe 1; base pipe 1 comprises first base pipe A and second base pipe B, both ends of first base pipe A and second base pipe B are connected with flange 4 respectively; inner lining layer 2 forms flange structure 6 at one end of flange 4 away from base pipe 1 at both ends of first base pipe A and second base pipe B, flange structure 6 is close to one end of flange 4 away from base pipe 1; multiple bolt holes 9 are evenly arranged on the same circumference of flange 4, bolt 5 is arranged through bolt hole 9, one end of bolt 5 is connected with nut 8, two flanges 4 are fastened and connected by bolt 5 and nut 8. Bolt 5 and nut 8 are used to connect two flanges 4.

[0033] The base pipe 1 is provided with welds 3 at both ends, and the flange 4 is welded to the base pipe 1 through the welds 3; the base pipe 1 and the flange 4 are both made of steel material; the lining layer 2 is inserted into the base pipe 1, and the lining layer 2 and the flange structure 6 are non-metallic pipes made of polyethylene or polypropylene. The flange structure 6 is formed by flanging the end of the flange 4 away from the base pipe 1 after the lining layer 2 is inserted into the base pipe 1. It is a non-metallic layer covering the end surface of the flange 4. The electric heating wire 7 is pressed into the flanging structure 6 while the flanging is being processed.

[0034] As an embodiment, a heating wire 7 is arranged in the flange structure 6 arranged on the first substrate A or the second substrate B;

[0035] As another embodiment, the flange structures 6 provided on the first substrate A and the second substrate B are both provided with heating wires 7 .

[0036] The heating wire 7 is arranged around the flange structure 6, and the flange structure 6 is a circular ring structure. A connecting terminal is respectively provided at both ends of the heating wire 7. The two connecting terminals are led out of the flange structure 6 for connecting to the electric fusion welding machine during on-site installation.

[0037] The outer diameter of the lining layer 2 is the same as the inner diameter of the base pipe 1 .

[0038] As an embodiment, the flange 4 and the base pipe 1 are made of the same or similar material and have good welding performance, and are connected by welding;

[0039] The size of flange 4 and the number and specifications of bolts 5 can refer to GB / T 9124-2019 "Steel Pipe Flange"; flange 4 is a welded neck flange, one end of the neck flange is a conical small head, which is welded to the base pipe 1, and the other end of the neck flange is a sealing surface, which plays a sealing role.

[0040] During on-site connection, the welding current and heating time of the electric fusion welding machine used need to be adjusted according to the specifications of the base pipe 1 and the material and thickness of the inner lining layer 2.

[0041] Example 2

[0042] A method for processing a hot-melt joint of a lined non-metallic composite steel pipe, comprising:

[0043] Flanges are welded at both ends of the base pipe 1, and the lining layer 2 is installed inside the base pipe 1. The length of the lining layer 2 is greater than the length of the base pipe 1 after the flange 4 is welded. A certain length of the lining layer 2 is reserved outside the end of the flange 4 away from the base pipe 1. The reserved lining layer 2 is heated and flanging, and the flanging structure 6 is attached to the flange 4. During the flanging process, the heating wire 7 is pressed into the flanging structure 6 set on the first base pipe A.

[0044] During on-site construction, the two flanges 4 are aligned and connected by bolts 5 and nuts 8. By adjusting the bolts 5 and nuts 8, a certain pre-tightening force is applied to the flanges; the bolts 5 pass through a plurality of bolt holes 9 evenly arranged on the same circumference of the flange 4 and are connected with the nuts 8; after the connection is completed, the terminal of the electric heating wire 7 is connected to the matching electric fusion welding machine and heated, the flange structure 6 arranged on the first base pipe A is in a molten state, and the lining material is fused into one under the action of the flange pre-tightening force, so that the flange structure 6 arranged on the first base pipe A is melted and well combined with the flange structure 6 arranged on the second base pipe B; after the flange structure 6 arranged on the first base pipe A is welded and cooled, the flange pre-tightening force is relaxed due to the welding deformation of the lining material, and the bolts 5 and nuts 8 are adjusted again to tighten the two flanges 4.

[0045] Example 3

[0046] Flanges are welded at both ends of the base pipe 1, and the lining layer 2 is installed inside the base pipe 1. The length of the lining layer 2 is greater than the length of the base pipe 1 after the flange 4 is welded. A certain length of the lining layer 2 is reserved outside the end of the flange 4 away from the base pipe 1. The reserved lining layer 2 is heated and flanging, and the flanging structure 6 is attached to the flange 4. During the flanging process, the heating wire 7 is pressed into the flanging structure 6 set on the second base pipe B.

[0047] During on-site construction, the two flanges 4 are aligned and connected by bolts 5 and nuts 8. By adjusting the bolts 5 and nuts 8, a certain pre-tightening force is applied to the flanges; the bolts 5 pass through a plurality of bolt holes 9 evenly arranged on the same circumference of the flange 4 and are connected with the nuts 8; after the connection is completed, the terminal of the electric heating wire 7 is connected to the matching electric fusion welding machine and heated, the flange structure 6 arranged on the second base pipe B is in a molten state, and the lining material is fused into one under the action of the flange pre-tightening force, so that the flange structure 6 arranged on the second base pipe B is melted and well combined with the flange structure 6 arranged on the first base pipe A; after the flange structure 6 arranged on the first base pipe A is welded and cooled, the flange pre-tightening force is relaxed due to the welding deformation of the lining material, and the bolts 5 and nuts 8 are adjusted again to tighten the two flanges 4.

[0048] Example 4

[0049] Flanges are welded at both ends of the base pipe 1, and the lining layer 2 is installed inside the base pipe 1. The length of the lining layer 2 is greater than the length of the base pipe 1 after the flange 4 is welded. A certain length of the lining layer 2 is reserved outside the end of the flange 4 away from the base pipe 1. The reserved lining layer 2 is heated and flanging, and the flanging structure 6 is attached to the flange 4. During the flanging process, the heating wire 7 is pressed into the flanging structure 6 set on the two base pipes.

[0050] During on-site construction, the two flanges 4 are aligned and connected by bolts 5 and nuts 8. By adjusting the bolts 5 and nuts 8, a certain preload force is applied to the flanges; the bolts 5 pass through a plurality of bolt holes 9 evenly arranged on the same circumference of the flanges 4 and are connected to the nuts 8; after the connection is completed, the terminal of the electric heating wire 7 is connected to the matching electric fusion welding machine and heated, the flange structures 6 arranged on the two base pipes are in a molten state, and the lining materials are fused into one under the action of the flange preload force, so that the flange structures 6 on the end faces of the two flanges 4 are melted and well combined; after the flange structures 6 on the end faces of the two flanges 4 are welded and cooled, the flange preload force is relaxed due to the welding deformation of the lining material, and the bolts 5 and nuts 8 are adjusted again to tighten the two flanges 4.

[0051] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A hot-melt joint for a lined non-metallic composite steel pipe, characterized in that: include: A base tube (1), an inner lining layer (2), a flange (4), bolts (5), a heating wire (7) and nuts (8); the inner lining layer (2) is arranged inside the base tube (1) and is arranged close to the inner wall of the base tube (1); the two ends of the base tube (1) are respectively connected to a flange (4); the inner lining layer (2) forms a flange structure (6) at one end of the flange (4) away from the base tube (1), and the flange structure (6) is arranged close to one end of the flange (4) away from the base tube (1); the two flanges (4) are fastened and connected by bolts (5) and nuts (8); and the heating wire (7) is arranged in the flange structure (6).

2. The hot-melt joint for lined non-metallic composite steel pipe according to claim 1, characterized in that: The base pipe (1) comprises a first base pipe (A) and a second base pipe (B), and both ends of the first base pipe (A) and the second base pipe (B) are respectively connected to a flange (4).

3. The hot-melt joint of a lined non-metallic composite steel pipe according to claim 2, characterized in that: The inner lining layer (2) forms a flange structure (6) at the end of the flange (4) at both ends of the first base pipe (A) and the second base pipe (B) which is away from the base pipe (1).

4. The hot-melt joint for lined non-metallic composite steel pipe according to claim 1, characterized in that: A plurality of bolt holes (9) are evenly arranged on the same circumference of the flange (4), and the bolts (5) are arranged to penetrate the bolt holes (9).

5. The hot-melt joint for lined non-metallic composite steel pipe according to claim 1, characterized in that: One end of the bolt (5) is connected to a nut (8).

6. The hot-melt joint of lined non-metallic composite steel pipe according to claim 3, characterized in that: An electric heating wire (7) is arranged in the flange structure (6) arranged on the first base tube (A) or the second base tube (B).

7. The hot-melt joint for lined non-metallic composite steel pipe according to claim 3, characterized in that: Electric heating wires (7) are arranged in the flange structures (6) arranged on the first base tube (A) and the second base tube (B).

8. The hot-melt joint for lined non-metallic composite steel pipe according to claim 1, characterized in that: The heating wire (7) is arranged around the flange structure (6), and a connecting terminal is respectively provided at both ends of the heating wire (7), and the two connecting terminals are connected to the electric fusion welding machine.

9. The hot-melt joint for lined non-metallic composite steel pipe according to claim 1, characterized in that: Welds (3) are provided at both ends of the base pipe (1), and the flange (4) is welded to the base pipe (1) via the welds (3).

10. A method for processing a hot-melt joint of a lined non-metallic composite steel pipe, characterized in that: A lined non-metallic composite steel pipe hot-melt joint according to any one of claims 1 to 9, comprising: Flanges are welded at both ends of the base pipe (1), and the inner lining layer (2) is installed inside the base pipe (1). The length of the inner lining layer (2) is greater than the length of the base pipe (1) after the flange (4) is welded. A certain length of the inner lining layer (2) is reserved outside the end of the flange (4) away from the base pipe (1). The reserved inner lining layer (2) is heated and flanging is performed, and the flanging structure (6) is attached to the end of the flange (4) away from the base pipe (1); during the flanging process, the electric heating wire (7) is pressed into the flanging structure (6); The two flanges (4) are aligned and connected by bolts (5) and nuts (8), and a certain pre-tightening force is applied to the flanges by adjusting the bolts (5) and nuts (8); after the connection is completed, the electric heating wire (7) is heated, and the two flange structures (6) are in a molten state, so that the two flange structures (6) are melted and combined; after the flange structures (6) are welded and cooled, the bolts (5) and nuts (8) are adjusted again to tighten the two flanges (4).

Images