A pipe coil heat exchanger using spherical clamps to secure the tube bundle

Abstract

The application provides a coiled tube heat exchanger using spherical clamping strips to fix tube bundles, and belongs to the technical field of heat exchange equipment, and comprises a central cylinder and a plurality of clamping strips with spherical protrusions arranged on the outer wall of the central cylinder. The upper surface of the clamping strip is provided with a spherical protrusion structure, and adjacent spherical protrusions constitute a heat exchange tube positioning element. The spacing between the spherical structures is optimized to match the arrangement of the tube bundles, and the outer surface of the central cylinder is wound with heat exchange tubes. The clamping strip with the spherical protrusion adopts a reverse stamping process in the manufacturing process, so that the processing surface is located on the non-contact side of the heat exchange tube, effectively avoiding direct friction damage of the processing defects to the tube wall. The spherical streamline structure reduces the turbulence intensity when the shell side fluid flows around, effectively reduces the shell side pressure drop while ensuring the positioning accuracy of the heat exchange tube, and improves the heat transfer efficiency of the heat exchanger. The clamping strip with the spherical protrusion omits the independent welding area required by the traditional tube clamp, thereby reducing the material consumption of the clamping strip.

Description

Technical Field

[0001] This application relates to the field of heat exchanger technology, and in particular to a tube-wound heat exchanger that uses spherical clips to fix the tube bundle. Background Technology

[0002] The wound-tube heat exchanger is a highly efficient and compact heat exchange device. Its advantages, including high operating pressure, high heat exchange efficiency, effective multi-channel fluidization, and self-compensation for thermal expansion, have led to its rapid application in fields such as petrochemicals. A wound-tube heat exchanger consists of multiple sets of heat exchange tubes spirally wound around a central cylinder at a predetermined helical angle to form a multi-layered tube bundle. Heat exchange tubes in the same layer are separated by spacers and racks to ensure precise control of the lateral and longitudinal spacing, while the winding direction of heat exchange tubes between adjacent layers is opposite. Compared to traditional heat exchangers, the wound-tube heat exchanger offers a significantly increased heat transfer area per unit volume. Counter-current or cross-flow arrangements significantly improve the heat transfer coefficient, and it maintains structural stability even under high pressure or extreme temperature conditions.

[0003] As one of the core structures of a wound tube heat exchanger, the heat exchange tube fixing clips mainly function to ensure the uniformity of the tube bundle arrangement by constraining the displacement of the heat exchange tubes, and to prevent mechanical damage to the heat exchange tubes under high pressure fluid impact or system vibration, thereby leading to a decrease in heat exchange performance.

[0004] Traditional serrated retaining strips, due to their toothed structure directly contacting the tube bundle, can cut the heat exchange tubes during vibration, potentially leading to tube wall wear after long-term operation. Furthermore, under cryogenic or high-temperature conditions, traditional serrated retaining strips are prone to low-temperature embrittlement or thermal stress fatigue fracture, causing unexpected displacement of the heat exchange tubes under extreme temperature conditions, exacerbating structural instability, and weakening the equipment's heat exchange performance.

[0005] Due to structural limitations, traditional serrated clamps cannot be directly welded to both sides of the serrated surface. Therefore, a transition area needs to be left on the clamp to accommodate the welding of the pipe clamp, which increases the amount of clamp material used per unit pipe bundle, raises manufacturing costs, and weakens the advantage of structural compactness. Summary of the Invention

[0006] This application provides a tube-wound heat exchanger that uses spherical clips to fix the tube bundle. It can be used to solve the technical problem that the tube-wound heat exchanger cannot operate stably for a long period of time under harsh operating conditions. While ensuring the positioning accuracy of the heat exchange tube, this application can extend the service life of the heat exchange tube, reduce frictional damage and local stress on the outer wall of the heat exchange tube, enhance heat exchange efficiency, and reduce the cost of using the fixing clips.

[0007] This application provides a tube-wound heat exchanger that uses spherical clips to fix the tube bundle, including a central cylinder located at the center, and an outer layer of the central cylinder with multiple layers of heat exchange tubes wound around it.

[0008] The outer wall of the central cylinder is provided with multiple fixing strips, and the upper surface of the fixing strips is provided with a spherical protrusion structure;

[0009] The outer surface of the central cylinder is wound with heat exchange tubes, which are spirally wound between adjacent spherical protrusions.

[0010] The heat exchange tubes wound around the outer layer of the central cylinder are the first layer of heat exchange tubes; the outer surface of the first layer of heat exchange tubes is welded with the second layer of fixing strips; thus forming a structure in which heat exchange tubes and fixing strips are stacked alternately until the outermost layer of heat exchange tubes is wound.

[0011] The winding directions of adjacent heat exchange tubes are opposite;

[0012] The fixing strips are evenly distributed on the outer surface of the central cylinder or each layer of heat exchange tubes, and the angle between two adjacent fixing strips in each layer is equal; the extension direction of the fixing strips is parallel to the axial direction of the central cylinder.

[0013] Furthermore, the spherical protrusion matches the outer diameter and helix angle of the heat exchange tube, and the spherical protrusion is externally tangent to the outer arc surface contour line of the heat exchange tube.

[0014] The fixing strip with spherical protrusions constrains the lateral and longitudinal spacing of the heat exchange tubes on the central cylinder by setting an array of spherical protrusions.

[0015] Furthermore, the spherical protrusion forms a continuous surface contact structure with the outer wall of the heat exchange tube by adjusting the radius of curvature.

[0016] The spherical protrusion is a round spherical protrusion with a radius of curvature that is less than 1 / 2 of the heat exchange tube radius r2, i.e., r1 < (1 / 2)r2; where r1 is the radius of curvature of the spherical protrusion.

[0017] Furthermore, the spacing between adjacent spherical protrusions is determined based on the outer diameter of the heat exchange tube corresponding to each layer and the helix angle.

[0018] Furthermore, the fixing strip with spherical protrusions is prepared by reverse stamping process, so that the processing defects generated during the stamping process are concentrated on the non-contact working surface of the strip. The defect area is then treated in a concentrated manner to ensure the smoothness of the contact surface.

[0019] Furthermore, the spherical protrusions are arranged in a high-precision array along the center line of the fixing strip, and the error in the spacing between adjacent spherical protrusions is within ±0.5mm.

[0020] Furthermore, the side of the innermost fixing strip that contacts the central cylinder conforms to the shape of the outer wall of the central cylinder;

[0021] The number of fixed strips (2) in each layer is greater than or equal to 2. In two adjacent layers, the number of fixed strips in the outer layer is the same as or greater than the number of fixed strips in the inner layer.

[0022] Furthermore, the spherical protrusion is an ellipsoidal protrusion.

[0023] It should be noted that the processes for creating ellipsoidal protrusions and spherical protrusions differ before stamping:

[0024] First, the dies used in progressive die stamping are different; the die shape varies depending on the shape of the protrusion.

[0025] The positioning of heat exchange tubes by spherical protrusions is mainly based on the outer diameter, while the positioning of heat exchange tubes by ellipsoidal protrusions is mainly based on the outer diameter of the shorter side of the ellipsoid.

[0026] In a tube-wound heat exchanger that uses spherical retaining strips to fix the tube bundle, the manufacturing steps for the retaining strips with spherical protrusions are as follows:

[0027] A. First, laser cutting is used to process multiple blank parts of fixing clips that meet the size requirements on a stainless steel substrate, and the cut edges are rounded to ensure that the surface roughness meets the requirements, forming pre-treated fixing clips;

[0028] B. The pre-treated fixing strips are formed into spherical continuous die stamping according to the spacing requirements through the stamping system, ensuring that key process parameters, including the spacing between adjacent spherical protrusions, forming radius, and wall roughness, meet the specified requirements.

[0029] C. Finally, apply pressure to the formed retaining strip and hold the pressure for a preset time to suppress elastic recovery, thus completing the stamping of the retaining strip and obtaining a spherical retaining strip for the tube heat exchanger.

[0030] 1. The spherical protrusion fixing strip of this invention ensures uniform spacing between tubes through high geometric precision design, eliminating local flow velocity deviation problems. Simultaneously, its increased contact area forms a surface contact structure with the outer wall of the heat exchange tube, effectively reducing local stress concentration caused by point contact and significantly extending the service life of the heat exchange tube. The spherical streamlined structure further optimizes the shell-side flow field distribution, suppresses turbulence intensity generation, reduces pressure drop per unit area, and improves overall heat exchange performance.

[0031] 2. The spherical protrusion fixing strip of this invention is manufactured using a stamping process. By adjusting the spacing between adjacent spherical protrusions, it can adapt to different pipe diameter specifications, and the protrusions are externally tangent to the outer arc contour line of the heat exchange tube. Combined with reverse stamping technology, burrs, creases and other processing defects are concentrated on the non-contact side, avoiding the risk of direct friction between the processed surface and the heat exchange tube, and improving process compatibility.

[0032] 3. The spherical protrusion fixing strip of this invention eliminates the separate area required for traditional pipe clamp welding through integrated design, reducing material consumption. Moreover, the spherical structure has good anti-deformation characteristics under high pressure or extreme temperature conditions, which greatly reduces manufacturing costs while maintaining the long-term stability of the coiled tube heat exchanger. Attached Figure Description

[0033] Figure 1 A schematic diagram of a retaining strip with spherical protrusions for a coiled tube heat exchanger;

[0034] Figure 2 A bottom view of the fixed clip;

[0035] Figure 3 This is a top view of an embodiment of the present invention;

[0036] Figure 4 This is a partially enlarged structural diagram of the fixing strip in an embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of the fixing strip structure with ellipsoidal protrusions for the wound tube heat exchanger of the present invention.

[0038] In the diagram: 1-Central cylinder, 2-Fixing strip, 3-Spherical protrusion, 4-Heat exchange tube. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0040] The embodiments of this application will now be described in conjunction with the accompanying drawings.

[0041] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0042] like Figure 1-4 As shown, a tube-wound heat exchanger using spherical clips to fix the tube bundle includes a central cylinder 1. Multiple fixing clips 2 are provided on the outer wall of the central cylinder 1. The upper surface of the fixing clips 2 is provided with spherical protrusions 3. Heat exchange tubes 4 are wound around the outer surface of the central cylinder 1. The heat exchange tubes 4 are wound between adjacent spherical protrusions 3. The adjacent spherical protrusions 2 form a channel for positioning the heat exchange tubes 4.

[0043] Specifically, the fixing strip 2 and the spherical protrusion 3 of the present invention are integrally stamped by continuous die, eliminating the need for welding between them and thus eliminating the risk of weld fatigue. The root of the spherical protrusion 3 adopts a gradually transitioning rounded corner structure, and the stamping rounded corner can be finely adjusted according to the forming situation to ensure that key process parameters such as the spacing between adjacent spherical protrusions 3, radius of curvature, and wall roughness meet the specified requirements. The fixing strip 2 adopts a reverse stamping process, so that the stamping burrs and crease defects are concentrated on the non-contact side, ensuring the smoothness of the contact surface, avoiding the risk of friction damage between the processed surface and the heat exchange tube 4, and reducing the wear of the fixing strip 2 on the heat exchange tube 4 during the manufacturing process.

[0044] Specifically, such as Figure 3 , Figure 4 As shown, the fixing strip 2 constrains the lateral and longitudinal spacing of the heat exchange tube 4 on the central cylinder 1 through the array of spherical protrusions 3 on its upper surface. The spherical protrusions 3 are adapted to the helix angle of the heat exchange tube 4, and the spacing between adjacent spherical protrusions 3 can be adjusted to meet the positioning requirements of different heat exchange tubes. The spherical protrusions 3 are externally tangent to the outer arc contour line of the heat exchange tube 4. By adjusting the radius of curvature of the spherical protrusions 3, continuous surface contact between them and the outer wall of the heat exchange tube 4 is achieved, which improves process compatibility and can effectively reduce local stress concentration caused by point contact, preventing mechanical damage to the heat exchange tube 4. Under extreme temperature conditions, it is less prone to low-temperature embrittlement or thermal stress fatigue fracture than traditional serrated fixing strips, thus extending the service life of the fixing strip 2 and the heat exchange tube 4.

[0045] Specifically, such as Figure 3 , Figure 4 As shown, the spherical protrusions 3 are arranged in a high-precision array along the center line of the fixed clip 2. The spacing tolerance between adjacent spherical protrusions 3 is controlled within ±0.5mm. The spherical streamlined structure of the spherical protrusions 3 matches the tube bundle arrangement of the heat exchange tubes 4. While ensuring the positioning accuracy of the heat exchange tubes 4, the shell flow field distribution is further optimized, the generation of turbulence intensity is suppressed, the pressure drop per unit area is reduced, and the overall heat exchange performance is improved.

[0046] It should be noted that this application includes multiple layers of heat exchange tubes 4 and fixing strips 2; the spacing between each layer of heat exchange tubes 4 and the spherical protrusions 3 of the fixing strips 2 in their respective layers is adapted, that is, the spacing between adjacent spherical protrusions 3 is determined according to the outer diameter and helical angle of the heat exchange tubes 4 corresponding to their respective layers. The winding directions of two adjacent heat exchange tubes 4 are opposite.

[0047] Specifically, such as Figure 5 The coiled tube heat exchanger uses a fixing strip structure with ellipsoidal protrusions. Its stamping and installation processes can be carried out according to the spherical protrusion structure, ensuring that the dimensional accuracy and surface roughness meet the requirements.

[0048] The manufacturing steps for the retaining strip 2 with spherical protrusions are as follows:

[0049] A. First, laser cutting is used to process multiple blank parts of fixing clips that meet the size requirements on a stainless steel substrate, and the cut edges are rounded to ensure that the surface roughness meets the requirements, forming pre-treated fixing clips;

[0050] B. The pre-treated fixing strips are formed into spherical continuous die through the stamping system according to the spacing requirements, ensuring that key process parameters such as the spacing between adjacent spherical protrusions, the forming radius, and the wall roughness meet the specified requirements;

[0051] C. Finally, apply pressure to the formed retaining strip and hold the pressure for a period of time to suppress elastic recovery. This completes the stamping of the retaining strip and produces a spherical retaining strip for a coiled heat exchanger.

[0052] The working principle of this invention is as follows:

[0053] In use, the fixing clips 2 are first welded onto the central cylinder 1 according to the distribution requirements, so that the heat exchange tube 4 can be accurately placed within the spacing of the adjacent spherical protrusions. The spherical protrusions 3 are externally tangent to the outer arc surface contour line of the heat exchange tube 4, fixing the heat exchange tube 4 within the preset horizontal and vertical spacing, ensuring the stability of the tube bundle arrangement. Furthermore, the displacement of the heat exchange tube 4 due to vibration or thermal expansion and contraction can be avoided by welding tube clamps.

[0054] The foregoing has provided a detailed description of a spherical fixing strip for a wound-tube heat exchanger provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that, based on the core technical ideas of the present invention, those skilled in the art can make several improvements and modifications to the present invention within the scope of protection defined by the claims, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0055] The embodiments described above do not constitute a limitation on the scope of protection of this application.

Claims

1. A tube-wound heat exchanger using spherical clips to fix the tube bundle, characterized in that, It includes a central cylinder (1) located at the center, and an outer layer of the central cylinder with multiple layers of heat exchange tubes wound around it; The outer wall of the central cylinder is provided with a plurality of fixing strips (2), and the upper surface of the fixing strips (2) is provided with a spherical protrusion (3) structure; The outer surface of the central cylinder (1) is wound with heat exchange tubes (4), which are wound in a spiral between adjacent spherical protrusions (3). The heat exchange tubes wound around the outer layer of the central cylinder are the first layer of heat exchange tubes; the outer surface of the first layer of heat exchange tubes is welded with the second layer of fixing strips; thus forming a structure in which heat exchange tubes (4) and fixing strips (2) are stacked alternately until the outermost heat exchange tube is wound. The winding directions of two adjacent heat exchange tubes (4) are opposite; The fixing strips (2) are evenly arranged on the outer surface of the central cylinder or each layer of heat exchange tubes, and the angle between two adjacent fixing strips in each layer is equal; the extension direction of the fixing strips (2) is parallel to the axial direction of the central cylinder (1).

2. The tube-wound heat exchanger using spherical clips to fix the tube bundle according to claim 1, characterized in that... The spherical protrusion (3) matches the outer diameter and helical angle of the heat exchange tube (4), and the spherical protrusion (3) is externally tangent to the outer arc surface contour line of the heat exchange tube (4).

3. The tube-wound heat exchanger using spherical clips to fix the tube bundle according to claim 1, characterized in that, The spherical protrusion (3) is a spherical protrusion with a radius of curvature that is less than 1 / 2 of the heat exchange tube radius r2, i.e., r1 < (1 / 2)r2; where r1 is the radius of curvature of the spherical protrusion.

4. The tube-wound heat exchanger using spherical clips to fix the tube bundle according to claim 1, characterized in that, The spacing between adjacent spherical protrusions (3) is determined based on the outer diameter and helical angle of the heat exchange tube (4) corresponding to each layer.

5. The tube-wound heat exchanger using spherical clips to fix the tube bundle according to claim 1, characterized in that, The side of the innermost fixing strip (2) that contacts the central cylinder (1) conforms to the shape of the outer wall of the central cylinder (1); The number of fixed strips (2) in each layer is greater than or equal to 2. In two adjacent layers, the number of fixed strips in the outer layer is the same as or greater than the number of fixed strips in the inner layer.

6. The tube-wound heat exchanger using spherical clips to fix the tube bundle according to claim 1, characterized in that, The spherical protrusion fixing strip (2) is prepared by reverse stamping process.

7. The tube-wound heat exchanger using spherical clips to fix the tube bundle according to claim 1, characterized in that, The spherical protrusions (3) are arranged in an array along the center line of the fixing strip (2), and the spacing error between adjacent spherical protrusions (3) is within ±0.5mm.

8. A retaining strip with spherical protrusions for a wound tube heat exchanger according to claim 1, characterized in that... The spherical protrusion (3) is an ellipsoidal protrusion.

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