A spiral finned tube fixed tube sheet heat exchanger
By employing spiral flat tubes and a fixed tube sheet structure in a shell-and-tube heat exchanger, a three-dimensional spiral flow and self-supporting design are achieved, solving the problems of fouling, vibration, and low heat transfer efficiency in traditional heat exchangers, and providing a compact and efficient heat exchange solution.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LANPEC TECHNOLOGIES LIMITED
- Filing Date
- 2025-03-08
- Publication Date
- 2026-05-29
AI Technical Summary
Traditional shell-and-tube heat exchangers suffer from flow dead zones leading to scaling, vibration failure, and low heat transfer efficiency, especially in conditions containing suspended solids or easily crystallizing media. Furthermore, existing spiral flat tube heat exchangers lack compactness and vibration resistance in industrial applications.
Using spiral flat tubes as heat transfer elements, combined with a fixed tube sheet structure design, a three-dimensional spiral flow is formed, eliminating flow dead zones and enhancing heat transfer. Vibration is prevented by support rings and liner structures, and the bow-shaped baffles are eliminated, achieving a compact design.
It effectively prevents fouling, reduces pressure drop, improves heat transfer efficiency, reduces equipment footprint, eliminates flow-induced vibration, and provides efficient and reliable heat exchange performance.
Smart Images
Figure CN224302828U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of heat exchanger technology, specifically to a spiral flat tube fixed tube sheet heat exchanger. Background Technology
[0002] Shell-and-tube heat exchangers, as the most widely used heat exchange equipment in the industrial field, have maintained an irreplaceable position despite a century of technological development. Traditional shell-and-tube heat exchangers mostly use straight circular tubes as heat transfer elements and construct the shell-side flow channel through bow-shaped baffles. Although they have advantages such as reliable structure and mature manufacturing process, they have exposed many technical bottlenecks in actual operation: First, the shell-side fluid flows in a zigzag pattern between the baffles, which easily forms flow dead zones and leads to particle deposition. Under conditions containing suspended matter or easily crystallizing media, the scaling rate can reach 0.3-0.5 mm / month, which seriously affects the heat transfer efficiency. Second, tube bundle vibration is a prominent problem. Vibration failure caused by the lateral scouring of the tube bundle by the fluid accounts for more than 25% of the equipment failure rate. Third, the laminar flow bottom layer of traditional circular tubes is relatively thick, and the convective heat transfer coefficient is generally lower than 800 W / (m²·K), especially under high viscosity fluid conditions, the heat transfer performance is significantly reduced.
[0003] In recent years, the industry has implemented several technological improvements to address these issues. Particularly in enhancing heat transfer, corrugated pipes and internally finned tubes can increase the heat transfer coefficient to 1200-1500 W / (m²·K). However, the complex internal surface structure significantly increases the difficulty of fouling removal, requiring chemical cleaning 2-3 times more frequently. Especially in continuous production sectors such as oil refining and chemical processing, the frequent shutdowns for cleaning of traditional heat exchangers result in substantial economic losses.
[0004] Although spiral tube technology has been studied in academia for a long time, its industrial application has long been limited by the challenges of manufacturing processes and structural compatibility. Existing spiral tube heat exchangers mostly adopt U-shaped tubes or floating head structures. Current technologies mostly focus on improving a single performance aspect, failing to systematically solve the problem of synergistic optimization of structural compactness, vibration resistance, and anti-fouling properties, resulting in insufficient applicability of the equipment in space-constrained and complex media conditions.
[0005] Against this backdrop, there is an urgent need in this field to develop a new type of shell-and-tube heat exchanger that, while maintaining the reliability of the fixed tube sheet structure, achieves a comprehensive performance breakthrough in scale prevention, vibration suppression, and efficient heat transfer through innovation in heat transfer elements and flow field reconstruction, so as to meet the urgent needs of modern industry for compact, low-maintenance, and high-efficiency heat exchange equipment. Utility Model Content
[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a spiral flat tube fixed tube sheet heat exchanger. This heat exchanger boasts advantages such as resistance to scaling and clogging, ability to overcome fluid-induced vibrations, compact structure, and high heat transfer efficiency. It can be applied in heating and cooling applications in industrial production, particularly in workstations requiring high heat exchange efficiency while considering factors such as floor space, equipment investment, and energy conservation.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A spiral flat tube fixed tubesheet heat exchanger is disclosed. The heat exchanger is vertically positioned and includes a tube box, a shell, a tube bundle, a tube bundle liner, and a shell-side axial sealing structure. The tube box is welded to the shell, which consists of a shell-side cylinder and a tubesheet. The shell-side cylinder has inlet and outlet ports. The tube bundle uses spiral flat tubes as heat transfer elements, achieving self-support through point contact of the spiral lines on the outer edges of the tubes. The outer circumference of the tube bundle is bound with steel straps. The tube bundle liner wraps around the middle section of the bound tube bundle, with no liner near the inlet and outlet. The shell-side axial sealing structure is located at the inlet, sealing the cavity formed between the tube bundle liner and the shell-side cylinder.
[0009] The heat exchanger is a fixed tube sheet type, with the tube sheet, shell-side cylinder, and tube box being welded structures. The tube bundle is composed of spiral flat tubes as heat transfer elements, and the tube sheet adopts a full tube distribution structure.
[0010] The tube bundle is wrapped by a tube bundle liner, and a support ring is provided on the outside of the tube bundle liner.
[0011] The shell-side axial sealing structure includes bolts, nuts, washers, and sealing strips. Through holes are drilled in the support ring, washers, and sealing strips. Sealing strips are laid on the upper and lower surfaces of the support ring and pressed down with washers. The sealing strips and washers are pressed together by bolts and nuts.
[0012] The tube bundle liner is assembled and welded from a support ring, an inner liner, and support bars. The inner liner is a thin steel plate, which is laid as a whole within the frame composed of the support ring and support bars.
[0013] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0014] This invention achieves technological breakthroughs in scale prevention, heat transfer enhancement, vibration resistance, and compactness by using spiral flat tubes as the core heat transfer element and combining it with an optimized design of a fixed tubesheet structure. The unique spiral curved surface structure of the spiral flat tubes enables the shell-side fluid to form a continuous three-dimensional spiral flow. The resulting secondary flow effect creates a uniform shearing action on the tube wall surface, effectively disrupting the laminar sublayer required for fouling deposition, preventing blockage of the flow channels between tubes, and eliminating flow dead zones. The shell-side fluid can reach a turbulent state at relatively low flow velocities, with a particularly significant enhancement effect under viscous fluid conditions, effectively reducing pressure drop. The spiral flat tubes are arranged in a compact triangular pattern, combined with tube bundle liners and an integral support ring, designed as a fixed tubesheet heat exchanger to prevent shell-side fluid short-circuiting and reduce the equipment's footprint. The spiral winding structure gives the tube bundle self-supporting characteristics; after bundling the tube bundle, the traditional bow-shaped baffles can be completely eliminated, fundamentally eliminating the flow-induced vibration problem caused by baffle gaps. This invention solves the industry pain point of traditional shell-and-tube heat exchangers' inability to achieve multiple performance objectives simultaneously through the synergistic design of structural innovation and flow field optimization, providing an efficient and reliable solution for energy conservation, consumption reduction, and equipment upgrading in the process industry. Attached Figure Description
[0015] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.
[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0017] Figure 2 This is a schematic diagram of the tube bundle structure of this utility model;
[0018] Figure 3 This is a schematic diagram of the tube bundle liner structure of this utility model;
[0019] Figure 4 This is a schematic diagram of the shell-side axial sealing structure of this utility model;
[0020] In the diagram: 1. Tube box, 2. Shell, 3. Tube bundle, 4. Tube sheet, 5. Inlet, 6. Outlet, 7. Spiral flat tube, 8. Steel strip, 9. Tube bundle liner, 10. Support ring, 11. Shell-side axial sealing structure, 12. Inner liner, 13. Support strip, 14. Bolt, 15. Nut, 16. Washer, 17. Sealing strip. Detailed Implementation
[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model;
[0022] like Figure 1As shown. A spiral flat tube fixed tube sheet heat exchanger, its overall structure includes a tube box 1, a shell 2, a tube bundle 3, a tube sheet 4, a shell-side inlet 5, and a shell-side outlet 6. The tube box 1 is welded to the shell 2. The heat exchanger equipment is a vertical fixed tube sheet structure, and its specific structure is as follows: the shell-side cylinder is welded to the tube sheet 4 to form the shell 2, and the tube box 1 is welded to the tube sheet 4 and the shell 2 to form the equipment shell; the shell-side inlet 5 is set at the lower part of the shell 2, and the shell-side medium is set at the upper part, with the shell-side medium entering from the bottom and exiting from the top; the tube box 4 is equipped with a detachable tube box flat cover, and the tube-side connecting pipe is set on the flat cover, with the tube-side medium entering from the top and exiting from the bottom; the tube bundle 3 is inside the shell.
[0023] like Figures 2-4 The diagram shows a schematic of a spiral flat tube fixed tubesheet heat exchanger, including a spiral flat tube 7, a steel strip 8, a tube bundle liner 9, a support ring 10, and a shell-side axial sealing structure 11. The spiral flat tube 7 is welded and fixed to the tubesheets 4 at both ends. The point contact of the spiral line on the outer edge of the spiral flat tube 4 achieves self-support of the tube bundle 3. After the tube bundle 3 is welded to the tubesheet 4, it is bound with the steel strip 8. The tube bundle liner 9 is a detachable structure, consisting of upper and lower halves. Figure 3 The image shows a half of the tube bundle liner. The tube bundle liner 9 is welded together from a support ring 10, an inner liner 12, and a support bar 13. The inner liner 12 is a thin steel plate, which is laid in a whole within the frame composed of the support ring 10 and the support bar 13. The upper and lower halves of the tube bundle liner 9 are connected by bolts to wrap the middle section of the bundled tube bundle 3. The two ends of the tube bundle 3 near the tube sheet are the corresponding positions of the shell-side inlet 5 and the shell-side outlet 6 in the horizontal direction. The tube bundle liner 9 has a notch with an area equivalent to that of the shell-side inlet 5 and the shell-side outlet 6, so that the tube bundle 3 at this point is exposed and not wrapped by the tube bundle liner 9. A shell-side axial sealing structure 11 is provided on the first support ring 10 at the lowest end of the tube bundle liner 9. The shell-side axial sealing structure 11 includes bolts 14, nuts 15, washers 16, and sealing strips 17. Through holes are drilled on the support ring 10, the washers 16, and the sealing strips 17. Then, the sealing strips 17 are laid on the upper and lower surfaces of the support ring 10 and pressed down by the washers 16. The sealing strips 17 and washers 16 are pressed tightly by bolts 14 and nuts 15.
[0024] After the tube bundle liner 9 is installed, tie rods are set between the tube sheet 4 and the tube bundle liner 9 to restrict the axial movement of the tube bundle liner 9.
[0025] Sealing strip 17 is made of multi-layer thin steel strip, according to... Figure 4 After installation, fold both sides towards the direction tangent to the inner wall of the shell cylinder to seal the cavity formed between the inner liner and the shell cylinder.
[0026] After the upper and lower halves of the tube bundle liner 9 are installed, the inner liner 12 forms a cylinder that tightly wraps the tube bundle. The shell-side medium flows in the cylinder and exchanges heat fully with the spiral flat tube 7.
[0027] The flow path of the shell-side medium is as follows: medium enters shell-side inlet 5 → enters shell 2 → enters inner cavity of tube bundle liner 9 → shell-side outlet 6. The shell-side axial sealing structure 11 is located near shell-side inlet 5 to block the cavity formed between inner liner 9 and shell-side cylinder, preventing short circuit of the shell-side medium.
[0028] In the heat exchanger described in this invention, the tube side carries a medium prone to scaling and containing particles, while the shell side carries a relatively clean medium. The medium in the tube side flows from top to bottom, while the fluid in the shell side flows from bottom to top, resulting in a pure counter-current heat exchange between the hot and cold sides. The easily clogged solid particles flow from top to bottom and, under the influence of gravity, have a shorter residence time in the heat exchange tubes, making them less likely to accumulate on the inner wall of the tubes.
Claims
1. A spiral flat tube fixed tube sheet heat exchanger, comprising a tube box (1), a shell (2), a tube bundle (3), a tube bundle liner (9), and a shell-side axial sealing structure (11) installed within the shell, characterized in that, The tube box (1) is welded to the shell (2). The shell (2) is composed of a shell-side cylinder and a tube sheet (4). An inlet (5) and an outlet (6) are provided on the shell-side cylinder. The tube bundle (3) uses a spiral flat tube (7) as a heat transfer element. The tube bundle is self-supported by the point contact of the spiral line on the outer edge of the spiral flat tube (7). The outer periphery of the tube bundle (3) is bound with a steel strip (8). The tube bundle liner (9) wraps the middle section of the bound tube bundle. There is no liner near the inlet and outlet of the tube bundle. The shell-side axial sealing structure (11) is set at the inlet to seal the cavity formed between the inner liner and the shell-side cylinder.
2. A spiral flat tube fixed tube sheet heat exchanger according to claim 1, characterized in that, The heat exchanger is a fixed tube sheet type. The tube sheet (4) is welded to the shell cylinder and tube box (1). The tube bundle (3) is formed by spiral flat tubes (7) as heat transfer elements. The tube sheet (4) adopts a full tube structure.
3. A spiral flat tube fixed tube sheet heat exchanger according to claim 1, characterized in that, The tube bundle (3) is wrapped by the tube bundle liner (9), and a support ring (10) is provided on the outside of the tube bundle liner (9).
4. A spiral flat tube fixed tube sheet heat exchanger according to claim 3, characterized in that, The shell-side axial sealing structure (11) includes bolts (14), nuts (15), washers (16), and sealing strips (17). Through holes are drilled on the support ring (10), the washer (16), and the sealing strips (17). The sealing strips (17) are laid on the upper and lower surfaces of the support ring (10) and pressed down with washers (16). The sealing strips (17) and washers (16) are pressed together by bolts (14) and nuts (15).
5. A spiral flat tube fixed tube sheet heat exchanger according to claim 1, characterized in that, The tube bundle liner (9) is assembled and welded from the support ring (10), the inner liner (12) and the support bar (13). The inner liner (12) is a thin steel plate, which is laid in the frame composed of the support ring (10) and the support bar (13).