A double-pipe heat exchanger and a heat exchange system
By setting annular channels and corrugated fin units in the shell-and-tube heat exchanger, the heat transfer area and flow direction are increased, which solves the problems of poor heat transfer and leakage, and achieves the effects of efficient heat transfer and prevention of scaling.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI ZEPR ENG TECH CO LTD
- Filing Date
- 2025-06-17
- Publication Date
- 2026-06-19
AI Technical Summary
Existing shell-and-tube heat exchangers have poor heat transfer performance and are prone to leakage. In particular, they are prone to scaling when cooled by water. The large temperature difference between the hot and cold fluids leads to different expansion of the inner and outer tubes, resulting in a high risk of weld desoldering.
An annular channel is set between the inner and outer tubes, and multiple fin units are set on the outer wall of the inner tube. The fins are wavy and arranged along the axial direction of the inner tube. Each layer of fins is evenly spaced. The fluid convects in the annular channel, which increases the heat transfer area and the change of flow direction, and reduces the temperature difference between the hot and cold fluid ends.
It improves heat transfer efficiency, reduces the temperature difference between hot and cold fluids, avoids weld debonding and leakage, extends the service life of the equipment, and reduces scale buildup on the water side.
Smart Images
Figure CN224382202U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of heat exchange equipment, and relates to a shell-and-tube heat exchanger and heat exchange system. Background Technology
[0002] Currently, the shell-and-tube heat exchangers used in chemical production plants and waste gas and wastewater treatment plants are simple structures with inner and outer tubes. Their advantages are simple structure and ease of manufacture. Disadvantages include limited heat transfer area, poor heat transfer effect, and large temperature difference between the inlet and outlet ends. Due to the large temperature difference between the hot and cold fluids, the inner and outer tubes of the shell-and-tube heat exchanger expand differently under heat, which can cause weld detachment and leakage. When traditional shell-and-tube heat exchangers are used for water cooling, the large temperature difference between the hot and cold fluids makes the cooling water side susceptible to scaling due to the cooling water quality, thus affecting heat transfer efficiency. Utility Model Content
[0003] The purpose of this invention is to solve the problems of poor heat transfer efficiency and easy leakage in existing shell-and-tube heat exchangers, and to provide a shell-and-tube heat exchanger and heat exchange system. The shell-and-tube heat exchanger of this invention has the advantages of simple structure, ease of manufacture, high heat transfer efficiency, reducing the temperature difference between the hot and cold fluid end faces to eliminate the difference in thermal expansion between the inner and outer tubes of the heat exchanger, and preventing scale formation on the water side when used for water-cooled heat exchange.
[0004] This utility model solves the above-mentioned technical problems through the following technical solutions:
[0005] This utility model provides a shell-and-tube heat exchanger, which includes an inner tube and an outer tube sleeved outside the inner tube, with an annular channel between the inner tube and the outer tube; multiple layers of fin units are provided on the outer wall of the inner tube, and the multiple layers of fin units are located in the annular channel; each layer of fin unit includes a plurality of corrugated fins arranged at equal intervals along the circumference of the inner tube, and the corrugated fins are arranged along the axial direction of the inner tube; the corrugated fins in every two adjacent layers of fin units are arranged at uniform intervals along the circumference of the horizontal projection plane of the inner tube.
[0006] The inner tube has a first inlet and a first outlet at both ends, and the outer tube has a second inlet and a second outlet at both ends. The second inlet and the second outlet are connected to the annular channel. The first inlet is far from the second inlet, so that the fluid in the inner tube and the fluid in the annular channel can convect.
[0007] The shell-and-tube heat exchanger of this invention not only improves heat exchange efficiency (the flow direction of the heat exchange fluid changes continuously, making the fluid turbulent, increasing the heat transfer coefficient, and thus increasing the heat transfer efficiency), but also increases the heat exchange area. In addition, it reduces the temperature difference between the end face and cross section between the hot and cold fluids, thereby reducing the difference in thermal expansion between the inner and outer tubes of the shell-and-tube heat exchanger and avoiding leakage caused by the detachment of the heat exchange tube weld.
[0008] In this invention, the wavy fin preferably includes at least two arc-shaped curved plates connected end to end, and the bending directions of adjacent arc-shaped curved plates are opposite.
[0009] Preferably, the number of crests or troughs on the wavy fin is 2 to 6.
[0010] Preferably, the length of the wavy fin is 50-160 mm, and the length refers to the length along the axial direction of the inner tube.
[0011] Preferably, the peak value of the wave crest or trough of the wave-shaped fin is 5 to 20 mm.
[0012] Within the aforementioned optimal parameter range, the curvature of the wave crests and troughs is within a favorable range, resulting in low flow resistance and turbulent flow of the heat exchange fluid. A larger curvature increases the number of wave crests or troughs, increasing the resistance of the fluid outside the pipe and improving the heat exchange effect. Conversely, a smaller curvature reduces the variation in the flow direction of the heat exchange fluid, decreasing the number of wave crests or troughs, lowering the resistance of the fluid outside the pipe, and worsening the heat exchange effect.
[0013] In this invention, preferably, the projections of the wavy fins in two adjacent finned units onto the vertical plane overlap by 1 / 4 to 1 / 3 of the length of the wavy fins, where the vertical plane refers to a plane parallel to the axial direction of the inner tube. This preferred embodiment results in low fluid flow resistance and turbulent flow. A larger overlap length leads to excessive resistance, while a smaller overlap results in less variation in fluid flow direction, less pronounced turbulence, and poor heat transfer efficiency.
[0014] In this invention, the number of wavy fins in each fin unit is preferably 3 to 5, for example 4.
[0015] In this invention, a gap of 1-3 mm is provided between the end of the wavy fin away from the inner tube and the inner wall of the outer tube.
[0016] In this invention, preferably, caps are provided at both ends of the outer tube to seal both ends of the outer tube, and the sides of the two caps are respectively provided with a second inlet and a second outlet. By placing the second inlet and the second outlet on the sides of the caps, interference with the first inlet and the first outlet on the inner tube is avoided.
[0017] This utility model also provides a heat exchange system, which includes at least two sets of the aforementioned shell-and-tube heat exchangers, wherein the first inlet on the inner tube of the at least two sets of the shell-and-tube heat exchangers is connected in parallel, and the first outlet on the inner tube of the at least two sets of the shell-and-tube heat exchangers is connected in parallel.
[0018] In this invention, the heat exchange system further includes a first fluid concentrator and a second fluid concentrator. All the first inlets are connected in parallel to the first fluid concentrator, and all the first outlets are connected in parallel to the second fluid concentrator. The first and second fluid concentrators form a buffer space for feeding and discharging, allowing the fluid to enter each inner tube more evenly.
[0019] The first fluid collection box and the second fluid collection box are provided with inlets and outlets, and the inlets and outlets are far apart from each other.
[0020] This utility model also provides a heat exchange system, which includes at least two sets of the aforementioned shell-and-tube heat exchangers, wherein the inner tubes of the at least two sets of the shell-and-tube heat exchangers are connected in series.
[0021] The shell-and-tube heat exchanger of this invention is more suitable for heat exchange equipment with low pressure fluids or low resistance requirements in chemical plants and waste gas and wastewater treatment plants.
[0022] The positive and progressive effects of this utility model are as follows:
[0023] (1) The corrugated fins on the heat exchange tube of this utility model can increase the heat transfer area, thereby increasing the effective heat exchange area of the shell-and-tube heat exchanger and making the heat exchange load capacity large.
[0024] (2) The flow direction of the heat exchange fluid in the jacket of the shell-and-tube heat exchanger of this utility model is constantly changing, which makes the fluid in a turbulent state, increases the heat transfer coefficient, and thus increases the heat transfer efficiency. In addition, since the fluid constantly changes the flow direction in the annular channel between the inner and outer tubes, it has a scouring effect on the tube wall, which is not easy to cause scaling and will not reduce the heat exchange effect of the heat exchanger.
[0025] (3) The heat transfer efficiency of the shell-and-tube heat exchanger of this utility model is high, the temperature difference between the hot and cold fluids at the end faces of the heat exchange is small, the thermal stress of the heat exchange tube is well eliminated, and the service life of the equipment is long.
[0026] (4) The shell-and-tube heat exchanger of this utility model has a simple structure and is easy to manufacture. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of the structure of a shell-and-tube heat exchanger according to a preferred embodiment of the present invention.
[0028] Figure 2 This is a partial structural diagram of the inner tube according to a preferred embodiment of the present invention.
[0029] Figure 3 This is a partial structural schematic diagram of a heat exchange system according to a preferred embodiment of the present invention.
[0030] Figure 4 This is a partial structural diagram of a heat exchange system according to another preferred embodiment of the present invention.
[0031] Explanation of reference numerals in the attached figures:
[0032] 1-Inner tube, 2-Outer tube, 3-Finned unit, 4-Annular channel, 5-First fluid concentration box, 6-Second fluid concentration box;
[0033] 101 - First import, 102 - First export;
[0034] 201 - Second Inlet, 202 - Second Outlet, 203 - Pipe Cap;
[0035] 31-Wave-shaped fins; 311-Arc-shaped curved plate. Detailed Implementation
[0036] The present invention is further illustrated below by way of embodiments, but these embodiments do not limit the present invention to the scope of the embodiments described. Experimental methods in the following embodiments that do not specify specific conditions are performed according to conventional methods and conditions, or as selected according to the product instructions.
[0037] One embodiment of this utility model discloses a shell-and-tube heat exchanger, such as Figure 1 and Figure 2 As shown, it includes an inner tube 1 and an outer tube 2 sleeved outside the inner tube 1, with an annular channel 4 between the inner tube 1 and the outer tube 2; multiple fin units 3 are provided on the outer wall of the inner tube 1, and the multiple fin units 3 are located in the annular channel 4; each fin unit 3 includes four wavy fins 31 arranged at equal intervals along the circumference of the inner tube 1, and the wavy fins 31 are arranged along the axial direction of the inner tube 1; the wavy fins 31 in each two adjacent fin units 3 are arranged at equal intervals along the circumference of the horizontal projection plane of the inner tube 1.
[0038] In this embodiment, the corrugated fin 31 includes four arc-shaped curved plates 311 connected end to end, with adjacent arc-shaped curved plates 311 bending in opposite directions, resulting in two crests and two troughs on the corrugated fin 31. The length of the corrugated fin 31 is 50–160 mm, and the vertical distance between adjacent crests and troughs on the corrugated fin 31 is 5–20 mm. The projections of the corrugated fins 31 in adjacent fin units onto the vertical plane overlap by 1 / 4 to 1 / 3 of the length of the corrugated fin 31, where the vertical plane refers to the plane parallel to the axial direction of the inner tube 1. A gap of 1–3 mm is provided between the end of each corrugated fin 31 furthest from the inner tube 1 and the inner wall of the outer tube 2.
[0039] The inner tube 1 has a first inlet 101 and a first outlet 102 at both ends, and the outer tube 2 has a second inlet 201 and a second outlet 202 at both ends. The second inlet 201 and the second outlet 202 are connected to the annular channel 4. The first inlet is far away from the second inlet, so that the fluid in the inner tube 1 and the fluid in the annular channel 4 can convect.
[0040] The outer tube 2 is provided with caps 203 at both ends, which seal the two ends of the outer tube 2. The two caps 203 are respectively provided with a second inlet 201 and a second outlet 202 on their sides.
[0041] The above-described shell-and-tube heat exchanger in this embodiment can increase the heat transfer area and continuously change the flow direction of the heat exchange fluid outside the tube, so that the fluid is in a turbulent state, which increases the heat transfer coefficient and thus increases the heat transfer efficiency. In addition, since the fluid continuously changes the flow direction in the annular channel 4 between the inner tube 1 and the outer tube 2, it has a scouring effect on the tube wall and is not prone to scaling.
[0042] Another embodiment of this utility model discloses a heat exchange system, such as Figure 3 As shown, it includes at least two sets of the aforementioned shell-and-tube heat exchangers, with the first inlet 101 on the inner tube 1 of the at least two sets of shell-and-tube heat exchangers connected in parallel, and the first outlet 102 on the inner tube 1 of the at least two sets of shell-and-tube heat exchangers connected in parallel.
[0043] In another embodiment of the heat exchange system of this utility model, the heat exchange system further includes a first fluid concentrator 5 and a second fluid concentrator 6. All first inlets 101 are connected in parallel to the first fluid concentrator 5, and all first outlets 102 are connected in parallel to the second fluid concentrator 6. The first fluid concentrator 5 and the second fluid concentrator 6 are provided with inlets and outlets, and the inlets and outlets are far apart from each other. The first fluid concentrator 5 and the second fluid concentrator 6 form a buffer space for feeding and discharging, so that the fluid can enter each inner tube 1 more evenly.
[0044] Another embodiment of this utility model discloses a heat exchange system, such as Figure 4 As shown, it includes at least two sets of the aforementioned shell-and-tube heat exchangers, with the inner tubes 1 of the at least two sets of shell-and-tube heat exchangers connected in series.
Claims
1. A double-pipe heat exchanger, characterized by, It includes an inner tube and an outer tube sleeved outside the inner tube, with an annular channel between the inner tube and the outer tube; multiple layers of fin units are provided on the outer wall surface of the inner tube, and the multiple layers of fin units are located in the annular channel; each layer of fin unit includes multiple wavy fins arranged at equal intervals along the circumference of the inner tube, and the wavy fins are arranged along the axial direction of the inner tube; the wavy fins in every two adjacent layers of fin units are arranged at uniform intervals along the circumference of the horizontal projection plane of the inner tube. The inner tube has a first inlet and a first outlet at both ends, and the outer tube has a second inlet and a second outlet at both ends. The second inlet and the second outlet are connected to the annular channel. The first inlet is far from the second inlet, so that the fluid in the inner tube and the fluid in the annular channel can convect.
2. The tube-in-tube heat exchanger of claim 1, wherein, The wavy fin includes at least two arc-shaped curved plates connected end to end, and the bending directions of adjacent arc-shaped curved plates are opposite.
3. The tube-in-tube heat exchanger of claim 2, wherein, The number of crests or troughs on the wavy fin is 2 to 6; And / or, the length of the corrugated fin is 50 to 160 mm, where the length refers to the length along the axial direction of the inner tube; And / or, the peak value of the crest or trough of the wavy fin is 5 to 20 mm.
4. The tube-in-tube heat exchanger of claim 1, wherein, The projections of the wavy fins in two adjacent fin units onto the vertical plane overlap by 1 / 4 to 1 / 3 of the length of the wavy fins, where the vertical plane is a plane parallel to the axial direction of the inner tube.
5. The tube-in-tube heat exchanger of claim 1, wherein, In each layer of the fin unit, the number of wavy fins is 3 to 5.
6. The tube-in-tube heat exchanger of claim 1, wherein, A gap of 1-3 mm is provided between the end of the wavy fin away from the inner tube and the inner wall of the outer tube.
7. The tube-in-tube heat exchanger of claim 1, wherein The outer tube is provided with caps at both ends, which seal the two ends of the outer tube. The two caps are respectively provided with a second inlet and a second outlet on their sides.
8. A heat exchange system, characterized by, It includes at least two sets of shell-and-tube heat exchangers as described in any one of claims 1 to 7, wherein the first inlet on the inner tube of the at least two sets of shell-and-tube heat exchangers is connected in parallel, and the first outlet on the inner tube of the at least two sets of shell-and-tube heat exchangers is connected in parallel.
9. The heat exchange system of claim 8, wherein, The heat exchange system further includes a first fluid collection box and a second fluid collection box, with all the first inlets connected in parallel to the first fluid collection box and all the first outlets connected in parallel to the second fluid collection box.
10. A heat exchange system, characterized by, It includes at least two sets of shell-and-tube heat exchangers as described in any one of claims 1 to 7, wherein the inner tubes of the at least two sets of shell-and-tube heat exchangers are connected in series.