Composite tube plate-tube internal shrinkage type welding structure

Abstract

The utility model relates to the technical field of petrochemical equipment, in particular to a composite tube plate-tube indentation type welding 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. The composite tube plate is provided with a plurality of tube holes for the composite heat exchange tubes to penetrate through in a one-to-one correspondence mode. A base body welding flux layer is arranged between a tube hole port of the tube plate base body and a port of the tube base body, a multi-layer welding flux layer is arranged between a tube hole of the tube plate multi-layer and a port of the tube multi-layer, and the multi-layer welding flux layer wraps the base body welding flux 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 the technical field of petrochemical equipment, in particular to a composite tube sheet-tube shrinkage type welding structure. Background Art

[0002] Shell-and-tube heat exchangers are a crucial component of petrochemical equipment. The welded joints between the tubesheet and the heat exchange tubes are both the most critical and the most susceptible to failure. Their quality directly impacts the equipment's service life and stability. The connection between the heat exchange tubes and the tubesheet is a primary site of product failure, and its reliability directly impacts product life. Welding, commonly known as tube-to-tubesheet welding, is the most common method for connecting the heat exchange tubes to the tubesheet. Tube-to-tubesheet welding is a critical step in the manufacturing of shell-and-tube heat exchangers.

[0003] Traditionally, welding heat exchange tubes to tubesheets involves inserting the tubes through the tubesheet, creating a groove on the tubesheet, and then welding the two together. For example, Chinese patent publication CN102151958A discloses a method for welding heat exchanger tubesheet-to-tube joints. During tube-to-tubesheet assembly, the tubesheet is recessed 0.5-1 mm from the tubesheet surface. This allows the tungsten electrode to easily penetrate the root of the angle between the tube and tubesheet, allowing the arc to reach the sharp corner during autogenous welding. Later, the applicant developed a heat exchanger tube head structure that ensures root penetration, as disclosed in Chinese patent document CN218455401U. The structure comprises a tube sheet and heat exchange tubes. The tube sheet has a tube hole, into which the end of the heat exchange tube is inserted. The end of the heat exchange tube is recessed 0.5 to 1 mm from the tube sheet surface. The end of the tube hole has an inverted frustum-shaped weld groove with an angle of 35° to 50° and a height of 1.5 to 2.5 mm. As an improvement, the bottom of the weld groove is provided with a transverse annular step around the periphery of the tube hole, and the transition between the annular step and the side wall of the weld groove is provided with a concave fillet. The step at the bottom of the weld groove widens the groove bottom, reduces the difficulty of fusing the root of the groove, and improves the pass rate. Furthermore, the concave fillet between the annular step and the weld groove makes the transition smoother, making it easier for the filler wire to reach the root position, ensuring root penetration.

[0004] The above tube sheets and heat exchange tubes are all single-layer structures, while for composite tube sheets and composite heat exchange tubes, the composite tube sheets include a tube sheet base and a tube sheet clad covering the outer surface of the tube sheet base. The composite heat exchange tubes include a tube base and a tube clad. The tube clad is passed through and covers the inner surface of the tube base. The tube sheet base and the tube base are generally made of high-temperature resistant, high-strength metals, while the tube sheet clad and the tube clad need to withstand the erosion of the medium and are generally made of corrosion-resistant, high-temperature resistant metals. However, the existing welding method is relatively crude and does not distinguish between the base layer and the clad. The traditional single-layer tube head welding method is used, that is, the tube head is simply welded and fixed. However, the inventors found that because the base layer is located on the inner side of the clad, the base layers are not fully welded during welding, or the base layer and the clad are made of different materials. This makes the welding strength between the tube sheet base as the main body and the tube base insufficient. Furthermore, in the prior art, some heat exchange tubes extend out of the tube sheet. After assembly, the tube sheet base is completely stored inside, and the tube sheet composite layer and the tube composite layer / tube base can only be welded. The strength of the tube head formed by welding needs to be improved. Summary of the Invention

[0005] In view of all or part of the above technical problems existing in the prior art, the utility model provides a composite tube sheet-tube shrinkage type welding structure.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] A composite tube sheet-tube shrink-in welding structure is provided, comprising a composite tube sheet and a plurality of composite heat exchange tubes. The composite tube sheet comprises a tube sheet base and a tube sheet cladding covering the outer side of the tube sheet base; the composite heat exchange tube comprises a tube base and a tube cladding, and the tube cladding is passed through and covers the inner side of the tube base.

[0008] The composite tube sheet is provided with a plurality of tube holes for correspondingly passing through a plurality of composite heat exchange tubes. The ends of the composite heat exchange tubes pass through the outer side surface close to the tube sheet substrate and retain a preset inward retraction distance.

[0009] A base solder layer is provided between the tube hole port of the tube sheet base and the port of the tube base, and a composite solder layer is provided between the tube hole of the tube sheet composite layer and the port of the tube composite layer, and the composite solder layer wraps the base solder layer.

[0010] As a further optional option, the aperture of the tube hole of the tube sheet cladding is larger than the aperture of the tube hole of the tube sheet base, thereby forming an annular material groove with an L-shaped cross section between the outer side surface of the tube sheet base and the hole wall of the tube hole of the tube sheet cladding, and the cladding solder layer and / or the base solder layer are also filled in the annular material groove.

[0011] As a further optional solution, the tube sheet substrate and the tube sheet cladding are made of dissimilar metals, and the tube substrate and the tube cladding are made of dissimilar metals; and / or: the tube sheet substrate, the tube substrate and the substrate solder layer are made of the same metal, and the tube sheet cladding, the tube cladding and the cladding solder layer are made of the same metal.

[0012] As a further alternative, the ports of the tube base body are arranged flush with the ports of the tube cladding.

[0013] As a further optional solution, the shrinkage distance of the tube cladding is greater than the shrinkage distance of the tube base, so that the inner wall of the port of the tube base is partially radially covered by the cladding solder layer and / or the base solder layer.

[0014] As a further optional solution, the outer surface of the clad solder layer is polished into a smooth streamlined shape.

[0015] As a further alternative, the cladding solder layer is flush with the outer side of the tube sheet cladding and the inner surface of the tube cladding.

[0016] As a further optional solution, the base solder layer and / or the clad solder layer is a spiral solder structure.

[0017] As a further optional solution, the base solder layer and / or the clad solder layer is a single-layer annular structure or a multi-layer annular structure.

[0018] As a further alternative, the thickness of the tube sheet cladding is smaller than the thickness of the tube sheet base body, and the thickness of the tube cladding is smaller than the thickness of the tube base body.

[0019] Beneficial effects of the utility model:

[0020] This new composite tube sheet-tube retracted welded structure, compared to existing technologies, features a composite double-layer structure for both the tube sheet and the heat exchange tubes. During welding, the annular gap between the tube sheet base and the tube base is first welded and secured, followed by the tube sheet and tube layers. This ensures a secure weld and connection strength between the tube sheet base and the tube base. Furthermore, the ends of the composite heat exchange tubes are retracted into the tube holes rather than protruding outside the composite tube sheet, preventing them from being eroded by media during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of the composite tube sheet and the composite heat exchange tube in the embodiment, which are in the state of being assembled but not welded.

[0022] Figure 2 Schematic diagram of a composite tube sheet-tube shrinkage welding structure in an embodiment.

[0023] Figure 3Schematic diagram of the structure of the composite tube sheet and composite heat exchange tube in another embodiment, which are in a state of being assembled but not welded.

[0024] Figure 4 Schematic diagram of a composite tube sheet-tube shrinkage welded structure in yet another embodiment.

[0025] Reference numerals:

[0026] Composite tube sheet 1, tube sheet base 11, tube sheet cladding 12, tube hole 13;

[0027] Composite heat exchange tube 2, tube base 21, tube cladding 22;

[0028] Base solder layer 3, composite solder layer 4, annular material groove 5. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0030] A composite tube sheet-tube shrinkage welding structure of this embodiment, such as Figures 1 to 2 As shown, the composite tube sheet 1 includes a composite tube sheet 1 and multiple composite heat exchange tubes 2 (only partially shown in the figure). The composite tube sheet 1 includes a tube sheet base 11 and a tube sheet cladding 12 covering the outer surface of the tube sheet base 11. Each composite heat exchange tube 2 includes a tube base 21 and a tube cladding 22, which is provided through and covers the inner surface of the tube base 21.

[0031] The composite tube sheet 1 has multiple tube holes 13 for correspondingly passing through multiple composite heat exchange tubes 2. The ends of the composite heat exchange tubes 2 are inserted close to the outer surface of the tube sheet base 11, leaving 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 inner side of the tube sheet base 11 until the ends of the composite heat exchange tubes 2 are within the preset distance from the outer surface of the tube sheet base 11. This is then positioned by a peripheral jig for welding.

[0032] During welding, the annular gap between the tube sheet base 11 and the tube base 21 is first welded and fixed, so that a base solder layer 3 is provided between the ends of the tube holes 13 of the tube sheet base 11 and the ends of the tube base 21, ensuring proper welding and connection strength between the tube sheet base 11 and the tube base 21. The tube sheet cladding 12 and the tube cladding 22 are then welded and fixed, so that a cladding solder layer 4 is provided between the tube holes 13 of the tube sheet cladding 12 and the ends of the tube cladding 22, and the cladding solder layer 4 envelops the base solder layer 3. Of course, while ensuring the respective weld structures between the tube sheet base 11 and the tube base 21, and between the tube sheet cladding 12 and the tube cladding 22, welding can also be performed between the tube sheet base 11 and the tube cladding 22, and between the tube sheet cladding 12 and the tube base 21, to achieve a more compact weld connection.

[0033] In this embodiment, the diameter of the tube hole 13 of the tube sheet cladding 12 is larger than the diameter of the tube hole 13 of the tube sheet base 11, thereby forming an annular groove 5 with an L-shaped cross section between the outer side surface of the tube sheet base 11 and the hole wall of the tube hole 13 of the tube sheet cladding 12, and the cladding solder layer 4 and / or the base solder layer 3 are also filled in the annular groove 5.

[0034] In practice, the tubesheet base 11 and tubesheet cladding 12 are made of dissimilar metals, while the tube base 21 and tube cladding 22 are also made of dissimilar metals. Furthermore, / or the tubesheet base 11, tube base 21, and base solder layer 3 are made of the same metal, while the tubesheet cladding 12, tube cladding 22, and cladding solder layer 4 are also made of the same metal. In summary, the base, as the primary component, is constructed of high-temperature-resistant, high-strength metal, while the tubesheet cladding 12, cladding solder layer, and tube cladding 22, which must withstand the erosion of the medium, are generally constructed of corrosion-resistant, high-temperature-resistant metals.

[0035] In this embodiment, the port of the tube base 21 is flush with the port of the tube cladding 22 .

[0036] Specifically, the outer surface of the composite solder layer 4 is polished to a smooth, streamlined shape. After welding, the polished surface is smooth and streamlined, without noticeable corners, to reduce erosion and wear. Similarly, the composite solder layer 4 is flush with the outer surface of the tube sheet cladding 12 and the inner surface of the tube cladding 22.

[0037] Specifically, the base solder layer 3 and / or the clad solder layer 4 have a spiral solder structure. During welding, the weld is performed around the annular seam between the ends of the tube holes 13 of the tube sheet base 11 and the ends of the tube base 21, and between the tube holes 13 of the tube sheet cladding 12 and the ends of the tube cladding 22. Multiple welds are performed, resulting in a multi-layered annular structure for the base solder layer 3 and the clad solder layer 4. Of course, a single-layer annular structure, i.e., a single weld, can be used as needed.

[0038] Specifically, the thickness of the tube sheet cladding 12 is smaller than the thickness of the tube sheet base 11 , and the thickness of the tube cladding 22 is smaller than the thickness of the tube base 21 .

[0039] Another embodiment is Figure 3 and Figure 4 As shown, the inward shrinkage distance of the tube cladding 22 is greater than the inward shrinkage distance of the tube base 21, so that the inner wall of the end of the tube base 21 is partially radially covered by the cladding solder layer 4 and / or the base solder layer 3. During manufacturing, the tube cladding 22 of the composite heat exchange tube 2 can be milled / grinded off in advance to form Figure 3 The purpose of the end shown is to avoid a larger area of ​​the end of the tube base 21, increase the mutual welding area between the tube base 21 and the tube sheet base 11, and further improve the fixing strength between the bases.

[0040] In the description of the present invention, it is obvious that the embodiments described are only some embodiments of the present invention, rather than all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0041] Therefore, the above detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention as claimed, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0042] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is typically placed when in use. These terms are intended solely to facilitate the description of this utility model and simplify the description, and are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," etc., etc., are used solely for distinction and should not be construed as indicating or implying relative importance.

[0043] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may refer to mechanical connections or electrical connections. They may refer to connections directly or indirectly through an intermediary, or they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

Claims

1. A composite tube sheet-tube shrinkage welded structure, characterized by: The composite tube sheet (1) comprises a composite tube sheet (1) and a plurality of composite heat exchange tubes (2), wherein the composite tube sheet (1) comprises a tube sheet base (11) and a tube sheet cladding (12) covering the outer side of the tube sheet base (11); the composite heat exchange tube (2) comprises a tube base (21) and a tube cladding (22), and the tube cladding (22) is provided through and covers the inner side of the tube base (21); The composite tube sheet (1) is provided with a plurality of tube holes (13) for a plurality of composite heat exchange tubes (2) to pass through in a one-to-one correspondence, and the ends of the composite heat exchange tubes (2) pass through the outer side surface close to the tube sheet base (11) and retain a preset inward retraction distance; A base solder layer (3) is provided between the end of the tube hole (13) of the tube sheet base (11) and the end of the tube base (21); a composite solder layer (4) is provided between the tube hole (13) of the tube sheet composite layer (12) and the end of the tube composite layer (22); and the composite solder layer (4) wraps the base solder layer (3).

2. The composite tube sheet-tube shrink-type welded structure according to claim 1, characterized in that: The diameter of the tube hole (13) of the tube sheet cladding (12) is larger than the diameter of the tube hole (13) of the tube sheet base (11), thereby forming an annular material groove (5) with an L-shaped cross section between the outer side surface of the tube sheet base (11) and the hole wall of the tube hole (13) of the tube sheet cladding (12), and the cladding solder layer (4) and / or the base solder layer (3) are also filled in the annular material groove (5).

3. The composite tube sheet-tube shrink-type welded structure according to claim 1, characterized in that: The tube sheet base (11) and the tube sheet cladding (12) are made of different metals, and the tube base (21) and the tube cladding (22) are made of different metals; and / or: the tube sheet base (11), the tube base (21) and the base solder layer (3) are made of the same metal, and the tube sheet cladding (12), the tube cladding (22) and the cladding solder layer (4) are made of the same metal.

4. The composite tube sheet-tube shrink-type welded structure according to claim 1, characterized in that: The ports of the tube base (21) and the ports of the tube cladding (22) are arranged flush with each other.

5. The composite tube sheet-tube shrink-type welded structure according to claim 1, characterized in that: The shrinkage distance of the tube cladding (22) is greater than the shrinkage distance of the tube base (21), so that the inner wall of the port of the tube base (21) is partially radially covered by the cladding solder layer (4) and / or the base solder layer (3).

6. The composite tube sheet-tube shrink-type welded structure according to claim 1, characterized in that: The outer surface of the composite solder layer (4) is polished into a smooth streamlined shape.

7. The composite tube sheet-tube shrink-type welded structure according to claim 1, characterized in that: The composite solder layer (4) is flush with the outer side surface of the tube plate composite layer (12) and the inner surface of the tube composite layer (22).

8. The composite tube sheet-tube shrink-type welded structure according to claim 1, characterized in that: The base solder layer (3) and / or the composite solder layer (4) is a spiral solder structure.

9. The composite tube sheet-tube shrink-in welded structure according to claim 1, characterized in that: The base solder layer (3) and / or the composite solder layer (4) is a single-layer annular structure or a multi-layer annular structure.

10. The composite tube sheet-tube shrink-type welded structure according to claim 1, characterized in that: The thickness of the tube sheet cladding (12) is smaller than the thickness of the tube sheet base (11), and the thickness of the tube cladding (22) is smaller than the thickness of the tube base (21).

Images