Flaring type step-by-step welding pipe head structure

Abstract

The utility model relates to the technical field of petrochemical equipment, in particular to a flaring type step-by-step welding tube head structure which comprises a composite tube plate and a plurality of composite heat exchange tubes, and the composite tube plate comprises a tube plate base body and a tube plate composite layer covering the outer side face of the tube plate base body. The composite heat exchange tube comprises a tube base body and a tube composite layer, and the tube composite layer is arranged on the inner side face of the tube base body in a penetrating and covering mode. A diameter expanding section is arranged at the end part of a tube hole of the tube plate base body, and the root part of the diameter expanding section is an inclined transition section; a chamfer is arranged on the outer side of the end of the pipe base body, an annular welding groove is defined by the chamfer and the transition section, the annular welding groove is provided with a primary welding flux layer, and a secondary welding flux layer is arranged between the pipe plate composite layer and the pipe composite layer. Compared with the prior art, the tube plate and the heat exchange tube are each of a composite double-layer structure, during welding, the annular gap between the tube plate base body and the tube base body is welded and fixed firstly, then the tube plate composite layer and the tube composite layer are welded and fixed, and therefore it can be guaranteed that welding and connecting strength exists between the tube plate base body and the tube base body.

Description

TECHNICAL FIELD

[0001] The utility model relates to petrochemical equipment technical field, concretely relates to a pipe head structure of flared type step-by-step welding. BACKGROUND

[0002] In petrochemical equipment, the tube-in-tube heat exchanger is an important equipment, and the welding joint of tube sheet and heat exchange tube is the most important and most likely to fail welding joint in the equipment, and its quality directly affects the service life of the equipment and the stability of the device. The connection between the heat exchange tube and the tube sheet is the main part of the product failure, and its reliability directly affects the service life of the product. The most common way to connect the heat exchange tube and the tube sheet is to use welding, which is commonly known as tube-tube sheet welding. In the production and manufacturing process of the shell-and-tube heat exchanger, tube-tube sheet welding is the most critical process.

[0003] The traditional heat exchange tube and tube sheet welding method generally involves passing the heat exchange tube through the tube sheet, opening a groove on the tube sheet, and then welding the two together. For example, the Chinese patent document CN102151958A discloses a welding method for the welding joint of a heat exchanger tube sheet and a heat exchange tube. In the assembly of the heat exchange tube and the tube sheet, a structure with a recess of 0.5-1mm on the surface of the tube sheet is used. In this way, the tungsten electrode can easily penetrate to the root of the heat exchange tube and tube sheet during welding, and the electric arc can reach the sharp corner position during self-fusion welding. Later, the applicant developed a heat exchanger pipe head structure that ensures root penetration, as disclosed in the Chinese patent document CN218455401U. The structure includes a tube sheet and a heat exchange tube. The tube sheet has a tube hole, and the end of the heat exchange tube is inserted into the tube hole. The end of the heat exchange tube is recessed into the surface of the tube sheet by 0.5-1mm. The end of the tube hole has a reverse conical welding groove with an angle of 35°-50° and a height of 1.5-2.5mm. As an improvement, the bottom of the welding groove is provided with a horizontally arranged annular step around the tube hole periphery, and the transition between the annular step and the side wall of the welding groove is provided with a concave round corner. The step at the bottom of the welding groove widens the bottom of the groove, reduces the difficulty of fusing the root of the groove, and improves the pass rate. Furthermore, the concave round corner between the annular step and the welding groove makes the transition smoother, and the root position is easier to reach during fillet welding, ensuring root penetration.

[0004] The tube plate and the heat exchange tube are both single-layer structures, while for the composite tube plate and the composite heat exchange tube, the composite tube plate comprises a tube plate base body and a tube plate composite layer covering the outer surface of the tube plate base body, and the composite heat exchange tube comprises a tube base body and a composite tube, the composite tube covering the inner surface of the tube base body, the tube plate base body and the tube base body are generally made of high-temperature and high-strength metal, while the tube plate composite layer and the composite tube need to withstand the erosion of the medium and are generally made of corrosion-resistant and high-temperature-resistant metal. However, the existing welding method is relatively rough, and the base layer and the composite layer are not distinguished, and the traditional single-layer tube head welding method is adopted, that is, the tube head is welded and fixed. However, the inventors found that since the base layer is located inside the composite layer, the base layer and the base layer are not fully welded during welding, or the base layer and the composite layer are welded with different materials, which makes the welding strength between the tube plate base body and the tube base body as the main body insufficient. Furthermore, the existing technology has a heat exchange tube penetrating out of the tube plate, and after assembly, the tube plate base body is completely hidden inside, and only the tube plate composite layer and the composite tube / tube base body can be welded, so the strength of the tube head formed by welding needs to be strengthened. SUMMARY

[0005] In view of all or part of the above technical problems existing in the prior art, the utility model provides a pipe head structure of flared type step-by-step welding.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical scheme:

[0007] A pipe head structure of flared type step-by-step welding is provided, comprising a composite tube plate and a plurality of composite heat exchange tubes, the composite tube plate comprising a tube plate base body and a tube plate composite layer covering the outer side surface of the tube plate base body; the composite heat exchange tube comprising a tube base body and a tube composite layer, the tube composite layer covering the inner side surface of the tube base body;

[0008] The composite tube plate is provided with a plurality of tube holes for the plurality of composite heat exchange tubes to correspondingly penetrate, the end of the composite heat exchange tube penetrating to the outer side surface close to the tube plate base body and retaining a preset distance of inward shrinkage; the end of the tube hole of the tube plate base body is provided with an enlarged diameter section with an increased hole diameter, and the root of the enlarged diameter section is a transition section with a gradually changed hole diameter; the end of the tube base body is provided with a chamfer, and the chamfer and the transition section enclose a V-shaped annular welding groove;

[0009] The annular welding groove is provided with a primary solder layer, and a secondary solder layer is arranged between the tube hole of the tube plate composite layer and the port of the tube composite layer, and the secondary solder layer wraps the primary solder layer.

[0010] Specifically, the hole diameter of the tube hole of the tube plate composite layer is equal to the hole diameter of the enlarged diameter section, so that the annular welding groove is outwardly open before welding.

[0011] Specifically, the hole diameter of the tube hole of the tube plate composite layer is equal to the hole diameter of the tube composite layer, and the secondary solder layer is flush with the hole wall of the tube hole of the tube plate composite layer and the inner wall of the tube composite layer.

[0012] Specifically, the tube plate base body and the tube plate composite layer are dissimilar metal bodies, and the tube base body and the tube composite layer are dissimilar metal bodies; and / or: the tube plate base body, the tube base body and the primary solder layer are the same metal body, and the tube plate composite layer, the tube composite layer and the secondary solder layer are the same metal body.

[0013] Specifically, the port of the tube base body is flush with the port of the tube composite layer.

[0014] Specifically, the inner shrinkage distance of the tube composite layer is greater than the inner shrinkage distance of the tube base body, so that the inner wall of the port of the tube base body is partially covered by the secondary solder layer.

[0015] Specifically, the secondary solder layer just fills the outer side surface of the tube plate base body and the end surface of the tube base body; or: the primary solder layer is lower than the outer side surface of the tube plate base body and the end surface of the tube base body, and the secondary solder layer is arranged between the tube plate base body and the tube base body and between the tube plate composite layer and the tube composite layer.

[0016] Specifically, the outer surface of the secondary solder layer is polished into a smooth streamline shape; and / or: the secondary solder layer is flushly connected to the outer side surface of the tube plate composite layer and the inner surface of the tube composite layer.

[0017] Specifically, the primary solder layer and / or the secondary solder layer is a spiral solder structure.

[0018] Specifically, the primary solder layer and / or the secondary solder layer is a single-layer annular structure or a multi-layer annular structure.

[0019] The beneficial effects of the utility model are:

[0020] Compared with the prior art, the tube plate and the heat exchange tube are both composite double-layer structures, the annular gap between the tube plate base body and the tube base body is welded and fixed first during welding, and then the tube plate composite layer and the tube composite layer are welded and fixed, so that the welding and connecting strength between the tube plate base body and the tube base body can be ensured. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The structure diagram of the composite tube plate and the composite heat exchange tube in the embodiment one is shown in the figure, which is in the state of alignment assembly without welding.

[0022] Figure 2 The structure diagram of the tube head structure of the embodiment one is shown in the figure.

[0023] Figure 3 The structure diagram of the tube head structure of the embodiment two is shown in the figure.

[0024] Figure 4 The structure diagram of the tube head structure of the embodiment three is shown in the figure.

[0025] Figure 5 This is a schematic diagram of the composite tube sheet and composite heat exchange tube in Example 4, showing the assembly process before welding.

[0026] Figure 6 This is a schematic diagram of a flared, step-welded pipe head structure in Example 4.

[0027] Figure label:

[0028] Composite tube sheet 1, tube sheet substrate 11, enlarged diameter section 111, transition section 112, tube sheet cladding 12, tube hole 13;

[0029] Composite heat exchange tube 2, tube base 21, chamfer 211, tube cladding 22;

[0030] 3. First solder layer, 4. Second solder layer, 5. Annular weld groove. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0032] Embodiment 1 of the flared, step-welded pipe head structure of this utility model, as follows: Figure 1 and Figure 2 As shown, the system includes a composite tube sheet 1 and multiple composite heat exchange tubes 2 (shown only partially in the figure). The composite tube sheet 1 includes a tube sheet substrate 11 and a tube sheet cladding 12 covering the outer surface of the tube sheet substrate 11. Each composite heat exchange tube 2 includes a tube substrate 21 and a tube cladding 22, with the tube cladding 22 penetrating and covering the inner surface of the tube substrate 21.

[0033] The composite tube sheet 1 has multiple tube holes 13 for multiple composite heat exchange tubes 2 to pass through in a one-to-one correspondence. The ends of the composite heat exchange tubes 2 extend to the outer side of the tube sheet substrate 11 and retain a preset inward distance of 0.5 to 3 mm. During assembly, the ends of the composite heat exchange tubes 2 are inserted from the inside of the tube sheet substrate 11 until the port of the composite heat exchange tube 2 is at a preset distance from the outer side of the tube sheet substrate 11, at which point it is positioned by an external fixture for welding. The ends of the tube holes 13 of the tube sheet substrate 11 are provided with an enlarged diameter section 111, and the root of the enlarged diameter section 111 is an inclined frustum-shaped transition section 112 with a gradually changing diameter. The outer side of the end of the tube substrate 21 is provided with a chamfer 211, and the chamfer 211 and the transition section 112 form a V-shaped annular weld groove 5.

[0034] The annular gap of the annular welding groove 5 is welded first to fix the annular gap, so that the annular welding groove 5 is filled with the first solder layer 3, and the welding and connecting strength between the tube plate base body 11 and the pipe base body 21 are ensured. Then, the tube plate complex layer 12 and the pipe complex layer 22 are welded to fix them, so that the tube hole 13 of the tube plate complex layer 12 and the port of the pipe complex layer 22 are provided with the second solder layer 4, and the second solder layer 4 wraps the first solder layer 3. Of course, on the basis of ensuring the welding structure between the tube plate base body 11 and the pipe base body 21 and between the tube plate complex layer 12 and the pipe complex layer 22 respectively, the tube plate base body 11 and the pipe complex layer 22 and the tube plate complex layer 12 and the pipe base body 21 can also be welded, so that the welding layer connection is more compact.

[0035] In the embodiment, the hole diameter of the tube hole 13 of the tube plate complex layer 12 is equal to the hole diameter of the diameter expansion section 111, so that the annular welding groove 5 is provided as an outward opening before welding, leaving a large space for welding the tube plate base body 11 and the pipe base body 21, and facilitating the formation of the arc-shaped streamline of the second solder layer 4.

[0036] In practice, the tube plate base body 11 and the tube plate complex layer 12 are dissimilar metal bodies, and the pipe base body 21 and the pipe complex layer 22 are dissimilar metal bodies; and / or: the tube plate base body 11, the pipe base body 21 and the first solder layer 3 are similar metal bodies, and the tube plate complex layer 12, the pipe complex layer 22 and the second solder layer 4 are similar metal bodies. In short, the base body is the main part, which adopts high-temperature-resistant and high-strength metal, while the tube plate complex layer 12, the second solder layer and the pipe complex layer 22 need to withstand the erosion of the medium, and generally adopt corrosion-resistant and high-temperature-resistant metal.

[0037] Specifically, the outer surface of the second solder layer 4 is polished into a smooth streamline shape, and the surface is polished to form a smooth streamline shape after welding, without obvious corners, reducing erosion and wear. Similarly, the second solder layer 4 is flushly connected to the outer side surface of the tube plate complex layer 12 and the inner surface of the pipe complex layer 22.

[0038] Specifically, the first solder layer 3 and / or the second solder layer 4 are spiral solder structures, and are welded around the annular gap between the tube hole 13 port of the tube plate base body 11 and the port of the pipe base body 21 and between the tube hole 13 of the tube plate complex layer 12 and the port of the pipe complex layer 22. Moreover, after multiple turns of welding, the first solder layer 3 and the second solder layer 4 are multi-layer annular structures. Of course, in practice, it can be changed to a single-layer annular structure according to needs, that is, one turn of welding is completed.

[0039] In the embodiment, Figure 2 As shown, the second solder layer 4 is filled to the outer side surface of the tube plate base body 11 and the end surface of the pipe base body 21. In the second embodiment, Figure 3As shown, the first solder layer 3 can be arranged below the outer side of the tube plate base 11 and the end face of the tube base 21, and the second solder layer 4 is arranged between the tube plate base 11 and the tube base 21 and between the tube plate composite layer 12 and the tube composite layer 22.

[0040] In the embodiment, the port of the tube base 21 is flush with the port of the tube composite layer 22. Figure 4 As shown, the inner shrinkage distance of the tube composite layer 22 is greater than the inner shrinkage distance of the tube base 21, so that the inner wall of the port of the tube base 21 is partially covered by the second solder layer 4. During manufacturing, the tube composite layer 22 of the composite heat exchange pipe 2 can be milled / grinded in advance, so as to avoid a larger area of the end of the tube base 21, facilitate welding of the tube base 21 and the tube plate base 11, and further improve the fixing strength between the bases.

[0041] As shown in the fourth embodiment, Figures 5 to 6 As shown, the hole diameter of the tube hole 13 of the tube plate composite layer 12 is equal to the hole diameter of the tube composite layer 22, so as to form a radial groove, and the surface of the second solder layer 4 is a plane flush with the hole wall of the tube hole 13 of the tube plate composite layer 12 and the inner wall of the tube composite layer 22.

[0042] In the description of the present application, obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0043] Therefore, the above detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0044] In the description of the present application, it should be explained that the terms "middle", "upper", "lower", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product is used, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0045] In the description of the utility model, it is necessary to explain, unless another explicit provision and limitation, term "arrange", "link", "connect" should do broad sense understanding, for example, can be fixed connection, also can be detachable connection, or integrally connected. Can be mechanical connection, can also be electrical connection. Can be directly connected, also can be indirectly connected through the intermediate medium, can be two elements inside the communication. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

Claims

1. A flared step-welded pipe end construction characterized by: The composite tube plate (1) comprises a tube plate base body (11) and a tube plate composite layer (12) covering the outer side of the tube plate base body (11); the composite heat exchange tube (2) comprises a tube base body (21) and a tube composite layer (22) covering the inner side of the tube base body (21); The composite tube plate (1) is provided with a plurality of tube holes (13) for the plurality of composite heat exchange tubes (2) to pass through one by one, and the end of the composite heat exchange tube (2) is inserted into the outer side of the tube plate base body (11) by a pre-set distance; the end of the tube hole of the tube plate base body (11) is provided with an expansion section (111) with an increased hole diameter, and the root of the expansion section (111) is an inclined transition section (112) with a gradually changed hole diameter; the outer side of the end of the tube base body (21) is provided with a chamfer (211), and the chamfer (211) and the transition section (112) form a V-shaped annular welding groove (5). The annular welding groove (5) is provided with a primary solder layer (3), and the tube hole (13) of the tube plate composite layer (12) and the port of the tube composite layer (22) are provided with a secondary solder layer (4), and the secondary solder layer (4) wraps the primary solder layer (3).

2. A flared stepped-welded pipe end structure according to claim 1, characterized in that: The hole diameter of the tube hole (13) of the tube plate composite layer (12) is equal to the hole diameter of the expansion section (111), so that the annular welding groove (5) is outwardly open before welding.

3. A flared stepped-welded pipe end structure according to claim 1, characterized in that: The hole diameter of the tube hole (13) of the tube plate composite layer (12) is equal to the hole diameter of the tube composite layer (22), and the secondary solder layer (4) is flush with the hole wall of the tube hole (13) of the tube plate composite layer (12) and the inner wall of the tube composite layer (22).

4. A flared stepped-welded pipe end structure according to claim 1, characterized by: The tube plate base body (11) and the tube plate composite layer (12) are dissimilar metal bodies, and the tube base body (21) and the tube composite layer (22) are dissimilar metal bodies; and / or: the tube plate base body (11), the tube base body (21) and the primary solder layer (3) are similar metal bodies, and the tube plate composite layer (12), the tube composite layer (22) and the secondary solder layer (4) are similar metal bodies.

5. A flared stepped-welded pipe end structure according to claim 1, characterized by: The port of the tube base body (21) is flush with the port of the tube composite layer (22).

6. A flared stepped-welded pipe end structure according to claim 1, characterized by: The retraction distance of the tube composite layer (22) is greater than the retraction distance of the tube base body (21), so that the inner wall of the port of the tube base body (21) is partially covered by the secondary solder layer (4) in the radial direction.

7. A flared stepped-welded pipe end structure according to claim 1, characterized by: The secondary solder layer (4) is just filled to the outer side of the tube plate base body (11) and the end surface of the tube base body (21); or: the primary solder layer (3) is lower than the outer side of the tube plate base body (11) and the end surface of the tube base body (21), and the secondary solder layer (4) is arranged between the tube plate base body (11) and the tube base body (21) and between the tube plate composite layer (12) and the tube composite layer (22).

8. A flared stepped-welded pipe end structure according to claim 1, characterized by: The outer surface of the secondary solder layer (4) is polished into a smooth streamline shape; and / or: the secondary solder layer (4) is flush with the outer side of the tube plate composite layer (12) and the inner surface of the tube composite layer (22).

9. A flared stepped-welded pipe end structure according to claim 1, characterized by: The primary solder layer (3) and / or the secondary solder layer (4) is a spiral solder structure.

10. A flared stepped-welded pipe end structure according to claim 1, characterized by: The primary solder layer (3) and / or the secondary solder layer (4) is a single-layer annular structure or a multi-layer annular structure.

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