A heat exchanger double tube plate welding structural member

Abstract

The utility model belongs to heat exchanger technical field, concretely relates to a heat exchanger double tube plate welding structural member. Heat exchanger double tube plate welding structural member includes: the tube side tube plate is provided with the boss at the right end part of the tube side board tube, is provided with the boss ring main part at the left end part of the shell side tube plate, is provided with the boss ring step at the left end part of the boss ring main part, the right end surface of the boss is with the left end surface of the boss ring main part coaxial contact, the inner side surface of the boss ring step is with the outer side surface of the boss adapts, the outer side surface of the boss ring step and the outer side surface of the boss are the welding position.

Description

Technical Field

[0001] This utility model belongs to the field of heat exchanger technology, specifically, it relates to a welded structure for a double tube sheet in a heat exchanger. Background Technology

[0002] A double tubesheet heat exchanger consists of two tube sheets on the shell and tube sides. The tube sheet connected to the tube box is called the tube-side tube sheet, and the tube sheet connected to the shell side is called the shell-side tube sheet. Double tubesheet heat exchangers are widely used in applications where mixing of the tube-side and shell-side media is strictly prohibited. This prevents hazards such as explosions, corrosion, and abnormal reactions caused by mixing of the tube-side and shell-side media. Commonly used double tubesheet types include integral, connected, and separate types. An integral double tubesheet typically consists of two forged tubesheets welded together, with an isolation cavity between them for monitoring potential leaks between the tubesheet and the heat exchange tubes.

[0003] While dual tubesheets offer significant advantages and superior performance, their manufacturing is extremely challenging, requiring stringent standards for tubesheet perpendicularity and concentricity of the tube holes on both tubesheets. In actual manufacturing, although the tube holes on the tube-side and shell-side tubesheets are drilled together, during reassembly and tube insertion, situations frequently arise where heat exchange tubes cannot pass through both tubesheets simultaneously. Even if the insertion problem is solved by reaming the holes, the insufficient expansion caused by the reaming further leads to leakage between the tubesheet and the heat exchange tubes.

[0004] Currently, the standards specify two main types of lock-bottom welded structures for integral double tubesheets: those with stress relief grooves and those with recessed grooves. Regardless of the structure, precise axial, radial, and circumferential positioning of the two tubesheets is required, resulting in cumbersome assembly processes and unsatisfactory results. Furthermore, the lock-bottom welded structures in the standards are prone to overheating and collapse. Due to the characteristics of integral double tubesheet structures, these welding defects cannot be subjected to non-destructive testing, easily leading to equipment operating with defects and creating safety hazards. In addition, engineering practice has shown that regardless of whether the tubesheet has a stress relief groove or a recessed groove structure, varying degrees of surface cracks appear at the grooved areas after service, seriously threatening the safe operation of the equipment and the entire process system. Therefore, the future development trend for double tubesheet heat exchangers is to develop and improve new connection structures and simplify assembly processes. Utility Model Content

[0005] In view of the technical problems mentioned above, the present invention aims to provide a double tube sheet welded structure for heat exchangers, which can solve at least one of the above technical problems.

[0006] According to this utility model, a double tube sheet welded structure for a heat exchanger is provided, comprising:

[0007] A boss is provided at the right end of the tube side plate.

[0008] A shell-side tube sheet is provided with a protruding ring body at the left end of the shell-side tube sheet, and a protruding ring step is provided at the left end of the protruding ring body.

[0009] The right end face of the boss is coaxially in contact with the left end face of the convex ring body, the inner side of the convex ring step is adapted to the outer side of the boss, and the outer side of the convex ring step and the outer side of the boss are welded parts.

[0010] In one specific embodiment, the outer side of the boss includes a first straight edge surface, which is parallel to the central axis of the boss and is adapted to the inner side of the protruding ring step.

[0011] In one specific embodiment, the outer side of the boss includes a first inclined surface, which is obliquely connected between the first straight surface and the right end face of the tube side plate. The first inclined surface is configured to increase the width of the molten pool during welding.

[0012] In one specific embodiment, a first arc surface is provided at the connection between the inner side of the convex ring body and the shell-side tube sheet, and the first arc surface is constructed to reduce stress concentration.

[0013] In one specific embodiment, a second straight edge surface is provided on the inner side of the convex ring body. The second straight edge surface is parallel to the central axis of the convex ring body and is tangent to the first arc surface.

[0014] In one specific embodiment, a second arc surface is provided at the connection between the outer side of the convex ring body and the shell-side tube sheet. The second arc surface is tangent to the outer side of the convex ring step, and the second arc surface is constructed to reduce stress concentration.

[0015] In one specific embodiment, the left end face of the shell-side tube sheet includes a second inclined surface, which is tangent to the second arc surface, and the second inclined surface is configured to increase the width of the molten pool during welding.

[0016] In one specific embodiment, the raised ring step is configured to completely melt during the welding process.

[0017] In one specific embodiment, an isolation cavity is formed on the inner side of the convex ring body.

[0018] In one specific embodiment, tube sheet holes for installing heat exchange tubes are provided axially through the tube sheet and the shell-side tube sheet. The outer side of the boss and the inner side of the convex ring step are matched, and the two have the same diameter. The outer side of the boss has a negative deviation, and the inner side of the convex ring step has a positive deviation. The difference between the two deviations is less than half of the difference between the tube sheet hole and the outer diameter of the heat exchange tube.

[0019] Compared with the prior art, the advantages of this application are as follows.

[0020] Both the tube-side tube sheet and the shell-side tube sheet are forgings. Forgings have superior machinability compared to sheet metal, and can be machined with high precision, which simplifies the subsequent assembly process of the tube-side tube sheet and the shell-side tube sheet.

[0021] The bosses on the tube-side tube sheet and the raised ring steps on the shell-side tube sheet form an isolation cavity, which facilitates monitoring whether leakage occurs between the heat exchange tubes and the two tube sheets.

[0022] The bosses on the tube-side tube sheet and the raised ring steps on the shell-side tube sheet fit together, eliminating the need to retain gaps at the root of the bevel, which facilitates the axial positioning of the two tube sheets and ensures their parallelism.

[0023] The outer side (first straight edge) of the boss on the tube-side tube sheet and the inner side of the convex ring step on the shell-side tube sheet are matched. The two have the same diameter, but the first straight edge has a negative deviation, while the inner side of the convex ring step has a positive deviation. The difference between the two deviations is less than half the difference between the tube sheet hole and the outer diameter of the heat exchange tube. This ensures that the radial positioning of the two tube sheets is completed after the two are matched, ensuring smooth tube insertion.

[0024] After the tube-side tube sheet and shell-side tube sheet are assembled, only the circumferential positioning of the tube holes needs to be finely adjusted to complete the assembly of the two tube sheets, which simplifies the assembly process and improves the assembly accuracy.

[0025] The outer side (first straight edge) of the boss on the tube side plate acts as a backing plate during the welding process, which can prevent defects such as overheating and collapse during welding. Attached Figure Description

[0026] The present invention will now be described with reference to the accompanying drawings.

[0027] Figure 1 A schematic diagram of one embodiment of a heat exchanger double tube sheet welded structure according to the present invention is shown.

[0028] Figure 2 A schematic diagram of one embodiment of the tube-side tube sheet of the heat exchanger double tube sheet welded structure according to the present invention is shown.

[0029] Figure 3 A schematic diagram of one embodiment of the shell-side tube sheet of a heat exchanger double tube sheet welded structure according to the present invention is shown.

[0030] Figure 4 This diagram shows an embodiment in which heat exchange tubes are interconnected with a double tube sheet welded structure of a heat exchanger according to the present invention.

[0031] Figure 5 and Figure 6A schematic diagram of a welded double tube sheet structure for a heat exchanger in the prior art is shown.

[0032] The reference numerals in the figure are as follows:

[0033] 1. Tube-side tube sheet; 2. Shell-side tube sheet; 3. Heat exchange tube; 4. Shell; 11. Boss; 111. First straight edge surface; 112. First beveled edge surface; 21. Protruding ring body; 211. First arc surface; 212. Second straight edge surface; 213. Protruding ring step; 214. Third straight edge surface; 215. Second arc surface; 216. Second beveled edge surface; 22. Isolation cavity; 31. Tube sheet hole; 10. Welded structure of double tube sheet for heat exchanger.

[0034] In this application, all the accompanying drawings are schematic drawings, used only to illustrate the principle of the present invention, and are not drawn to scale. Detailed Implementation

[0035] The present invention will now be described with reference to the accompanying drawings.

[0036] It should be noted that the directional terms or qualifiers used in this application, such as "up," "down," "left," and "right," are all specific to the referenced material. Figure 1 In other words, they are not used to define the absolute position of the components involved, but can vary depending on the specific circumstances.

[0037] Figure 1 The diagram shows the structure of the heat exchanger double tube sheet welded structure 10 according to the present invention. Only the upper half of the heat exchanger double tube sheet welded structure 10 is shown in cross-sectional view. Figure 1 As shown, the heat exchanger double tube sheet welded structure 10 mainly includes a tube-side tube sheet 1 and a shell-side tube sheet 2. The left side of the tube-side tube sheet 1 is coaxially connected to the pipes, and the right side of the shell-side tube sheet 2 is coaxially connected to the shell 4.

[0038] like Figure 1 and Figure 2 As shown, a boss 11 is provided at the right end of the tube-side plate 1. In this embodiment, the boss 11 is cylindrical and coaxially disposed at the right end of the tube-side plate 1. Furthermore, the boss 11 and the tube-side plate 1 are constructed as an integral structure.

[0039] like Figure 1 and Figure 3 As shown, a convex ring body 21 is provided at the left end of the shell-side tube sheet 2, and a convex ring step 213 is provided at the left end of the convex ring body 21. In this embodiment, the convex ring body 21 is constructed in a circular ring shape and is coaxially disposed at the left end of the shell-side tube sheet 2. The convex ring step 213 is constructed in a circular ring shape and is coaxially disposed at the left end of the convex ring body 21. Furthermore, the convex ring step 213, the convex ring body 21, and the shell-side tube sheet 2 are constructed as an integral structure.

[0040] In one specific embodiment, both the tube-side tube sheet 1 and the shell-side tube sheet 2 are forgings. Forgings, due to their isotropic nature, are suitable for high-precision machining.

[0041] The outer surface of the right end of the boss 11 is the first straight edge surface 111, which is parallel to the central axis of the boss 11. That is, the first straight edge surface 111 is constructed as a cylindrical surface. The diameter of the first straight edge surface 111 is adapted to the diameter of the inner surface of the convex ring step 213. Specifically, the diameter of the first straight edge surface 111 is equal to the diameter of the inner surface of the convex ring step 213, so that the convex ring step 213 can be coaxially fitted onto the outer side of the first straight edge surface 111 for positioning.

[0042] When assembling the tube-side plate 1 and the shell-side plate 2, the right end face of the boss 11 is in coaxial contact with the left end face of the convex ring body 21, and the inner side of the convex ring step 213 is adapted to the first straight edge surface 111 of the boss 11 for positioning. The outer side of the convex ring step 213 and the outer side of the boss 11 are the welding parts. Compared to Figure 5 and Figure 6 Compared with the existing double tube sheet V-shaped butt joint bevel, the assembly process of this utility model is simpler and the assembly accuracy is higher, and there is no need to process stress relief grooves or recesses.

[0043] In a specific embodiment, such as Figures 2-4 As shown, the inner diameter d of the convex ring body 21 is equal to the inner diameter of the shell 4. The diameter of the first straight edge 111 is 4 mm larger than the inner diameter of the shell 4, and the axial length b of the first straight edge 111 is 4 to 6 mm.

[0044] In a specific embodiment, such as Figure 1 and Figure 2 As shown, the outer side of the boss 11 includes a first inclined surface 112. The first inclined surface 112 is inclinedly connected between the first straight surface 111 and the right end face of the tube side plate 1. The first inclined surface 112 is configured to increase the width of the molten pool during welding and improve the axial strength of the weld.

[0045] like Figure 2 As shown, in this embodiment, the included angle α between the first beveled surface 112 and the tube-side plate 1 is 20-40°, preferably 30°, and the radial projection length a is 6mm. The 30-degree first beveled surface 112 forms a bevel to ensure the width of the molten pool, making it easier to observe the welding quality during welding. Limiting the axial projection length to 6mm is to prevent excessive cutting of the tube-side plate 1, which would cause unnecessary material waste.

[0046] In a specific embodiment, such as Figure 1 and Figure 3As shown, a first arc surface 211 is provided at the connection between the inner side of the convex ring body 21 and the shell side tube plate 2. The first arc surface 211 is constructed to reduce stress concentration.

[0047] In this embodiment, the radius R5 of the first arc surface 211 is 1 to 10 mm, preferably 5 mm.

[0048] In one specific embodiment, a second straight edge surface 212 is provided on the inner side of the convex ring body 21, and the second straight edge surface 212 is parallel to the central axis of the convex ring body 21. The second straight edge surface 212 is located to the left of the first arc surface 211 and is tangent to the first arc surface 211.

[0049] like Figure 3 As shown, in this embodiment, the diameter of the second straight edge 212 is equal to the inner diameter of the housing 4, and the axial length e is 5mm.

[0050] In one specific embodiment, a second arc surface 215 is provided at the connection between the outer side of the convex ring body 21 and the shell-side tube plate 2. The second arc surface 215 is tangentially connected to the outer side of the convex ring step 213. The second arc surface 215 is constructed to reduce stress concentration.

[0051] In this embodiment, the radius R6 of the second arc surface 215 is 1 to 10 mm, which is greater than the radius of the first arc surface 211. The radius R6 of the second arc surface 215 is preferably 6 mm.

[0052] In one specific embodiment, the outer surface of the convex ring step 213 is the third straight edge surface 214. For example... Figure 3 As shown, the diameter of the third straight edge 214 is 6mm larger than the inner diameter of the shell 4, and the axial length c of the third straight edge 214 is 2mm.

[0053] In one specific embodiment, the left end face of the shell-side tube sheet 2 includes a second inclined surface 216, which is located outside the convex ring body 21 and is tangentially connected to the second arc surface 215. The second inclined surface 216 is configured to increase the width of the molten pool during welding.

[0054] In this embodiment, the angle β between the second inclined surface 216 and the left end plane of the shell-side tube plate 2 is 20 to 40°, preferably 30°.

[0055] In one specific embodiment, the convex ring step 213 is configured to completely melt during the welding process.

[0056] In this embodiment, the boss 11 of the tube-side plate 1 overlaps with the raised ring step 213 of the shell-side plate 2 by 1-3 mm, preferably 2 mm, and the radial thickness of the raised ring step 213 is 1 mm. That is to say, as Figure 3As shown, the axial length c of the convex ring step 213 is 1-3 mm, preferably 2 mm, and the radial thickness of the convex ring step 213 is 1 mm. This configuration ensures assembly accuracy and ensures that the arc during welding completely melts the convex ring step 213, allowing the convex ring body 21 of the shell-side tube sheet 2 to be fully melted and formed a full-section welded joint.

[0057] In one specific embodiment, the length of the first straight edge 111 does not exceed 6mm and should not be too long, otherwise it will lead to an excessive increase in the amount of welding work.

[0058] like Figure 4 As shown, tube sheet holes 31 for installing heat exchange tubes 3 are axially provided on the tube-side tube sheet 1 and the shell-side tube sheet 2. The first straight edge surface 111 of the boss 11 mates with the inner surface of the convex ring step 213, and both have the same diameter. The outer surface of the first straight edge surface 111 has a negative deviation, and the inner diameter of the convex ring step 213 has a positive deviation. The difference between the two deviations is less than half the difference between the outer diameter of the tube sheet hole 31 and the outer diameter of the heat exchange tube 3. This arrangement ensures that the tube-side tube sheet 1 and the shell-side tube sheet 2 are radially positioned after mating, ensuring that the heat exchange tube 3 can smoothly pass through the tube sheet hole 31.

[0059] Optionally, the tolerances for the diameter of the first straight edge 111 of the circular boss 11 on the tube-side plate 1 and the inner diameter of the end ring step 213 on the shell-side plate 2 are shown in the following table:

[0060]

[0061] After the tube-side tube sheet 1 and the shell-side tube sheet 2 are assembled together, an isolation cavity 22 is formed on the inner side of the convex ring body 21 to monitor possible leaks between the tube sheet and the heat exchange tube 3. The axial length of the isolation cavity 22 is the sum of the axial length of the second straight edge surface 212 and the radius of the first arc surface 211. If the length of the isolation cavity 22 is too long, the rigidity of the convex ring body 21 will be low, and deformation will occur during machining, making it impossible to achieve the required machining accuracy.

[0062] Optionally, the weld leg height for welding the tube-side tube sheet 1 and the shell-side tube sheet 2 is equal to half the difference between the outer diameter of the shell-side tube sheet 1 and the inner diameter of the shell 4. The weld leg height ensures sufficient strength.

[0063] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0064] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and does not constitute any limitation on this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A welded structure for a double tube sheet in a heat exchanger, characterized in that, include: A boss (11) is provided at the right end of the tube side plate (1); Shell-side tube sheet (2), a protruding ring body (21) is provided at the left end of the shell-side tube sheet (2), and a protruding ring step (213) is provided at the left end of the protruding ring body (21); The right end face of the boss (11) is in coaxial contact with the left end face of the convex ring body (21), the inner side of the convex ring step (213) is adapted to the outer side of the boss (11), and the outer side of the convex ring step (213) and the outer side of the boss (11) are welded parts.

2. The heat exchanger double tube sheet welded structure according to claim 1, characterized in that, The outer side of the boss (11) includes a first straight edge surface (111), which is parallel to the central axis of the boss (11) and is adapted to the inner side of the convex ring step (213).

3. The heat exchanger double tube sheet welded structure according to claim 2, characterized in that, The outer side of the boss (11) includes a first inclined surface (112), which is inclinedly connected between the first straight surface (111) and the right end face of the tube side plate (1). The first inclined surface (112) is configured to increase the width of the molten pool during welding.

4. The heat exchanger double tube sheet welded structure according to claim 1, characterized in that, A first arc surface (211) is provided at the connection between the inner side of the convex ring body (21) and the shell side tube plate (2). The first arc surface (211) is constructed to reduce stress concentration.

5. The heat exchanger double tube sheet welded structure according to claim 4, characterized in that, A second straight edge surface (212) is provided on the inner side of the convex ring body (21). The second straight edge surface (212) is parallel to the central axis of the convex ring body (21) and is tangent to the first arc surface (211).

6. The heat exchanger double tube sheet welded structure according to claim 1, characterized in that, A second arc surface (215) is provided at the connection between the outer side of the convex ring body (21) and the shell side tube plate (2). The second arc surface (215) is tangent to the outer side of the convex ring step (213). The second arc surface (215) is constructed to reduce stress concentration.

7. The heat exchanger double tube sheet welded structure according to claim 6, characterized in that, The left end face of the shell-side tube sheet (2) includes a second inclined surface (216), which is tangent to the second arc surface (215). The second inclined surface (216) is configured to increase the width of the molten pool during welding.

8. The heat exchanger double tube sheet welded structure according to any one of claims 1 to 7, characterized in that, The convex ring step (213) is designed to completely melt during the welding process.

9. The heat exchanger double tube sheet welded structure according to any one of claims 1 to 7, characterized in that, An isolation cavity (22) is formed on the inner side of the convex ring body (21).

10. The heat exchanger double tube sheet welded structure according to any one of claims 1 to 7, characterized in that, Tube sheet holes for installing heat exchange tubes are provided axially through the tube sheet (1) and the shell-side tube sheet (2). The outer side of the boss (11) and the inner side of the convex ring step (213) are matched, and the two have the same diameter. The outer side of the boss (11) has a negative deviation, and the inner side of the convex ring step (213) has a positive deviation. The difference between the two deviations is less than half of the difference between the tube sheet hole and the outer diameter of the heat exchange tube.

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