A tubular heat exchanger with variable number of baffle arc tubes

Abstract

The application provides a tube-shell heat exchanger with variable number of baffle arc-shaped tubes, which is provided with a baffle in a shell of the tube-shell heat exchanger, and heat exchange tubes pass through the baffle; the baffle comprises a plurality of arc-shaped tubes; heat exchange fluids of the tube side and the shell side flow in a counter flow mode; along a flow direction of the fluid in the tube side, from a tube side inlet to a middle position of the tube side, the number of the arc-shaped tubes of the baffle is continuously reduced, and then from the middle position of the tube side to a tube side outlet, the number of the arc-shaped tubes of the baffle is continuously increased. The number of the baffle arc-shaped tubes is set to vary along the flow, and the non-uniformity of heat exchange amount is compensated by area variation, so that the heat exchange efficiency is further improved.

Description

Technical Field

[0001] This invention relates to a shell-and-tube heat exchanger, and more particularly to a shell-and-tube heat exchanger equipped with baffles. Background Technology

[0002] Heat exchangers are indispensable equipment for heat exchange and transfer in chemical production processes. In fields such as petrochemicals, cryogenic refrigeration, air separation, and seawater desalination, it is often necessary to heat cryogenic fluids or cool high-temperature fluids, and to vaporize liquids into steam or condense steam into liquids. These processes are all closely related to heat transfer and can therefore be accomplished using heat exchangers.

[0003] Commonly used heat exchangers include shell-and-tube heat exchangers and plate heat exchangers. Traditional shell-and-tube heat exchangers mostly use smooth tubes. Compared with various new plate heat exchangers, this traditional type has many disadvantages, such as low heat transfer efficiency and large size. However, shell-and-tube heat exchangers also have many advantages, such as simple manufacturing, resistance to high temperature and pressure, and convenient maintenance. Therefore, it is urgent to develop a double-sided enhanced high-efficiency heat exchanger based on the traditional shell-and-tube heat exchanger. Currently, some high-efficiency heat exchangers based on smooth tubes have been developed in China, but their heat transfer enhancement effect is not ideal.

[0004] To date, traditional high-efficiency heat exchangers mostly employ a single method to enhance heat transfer. One approach is to use rough-surface heat exchange tubes, creating de-edging flow by modifying the wall surface shape to disrupt the boundary layer and improve heat transfer performance within it. Examples include grooved tubes, spiral grooved tubes, longitudinal grooved tubes, corrugated tubes, swirl tubes, and finned tubes. Another approach is to use far-wall turbulence elements, generating continuous eddies that, under the influence of centrifugal force, ensure thorough mixing of the fluid at the tube center and the fluid in the wall boundary layer. However, using a single method results in less than ideal heat transfer performance.

[0005] Elastic tube bundle heat exchange components are a type of heat exchange structure first researched and developed by Shandong University. For example, Chinese invention patents "Floating Coil-Heat Pipe Two-Stage Heating Steam-Water Heat Exchanger" (application number: 92106727.5) and "Elastic Tube Bundle Steam-Water Heat Exchanger Unit" (application number: 94110563.6) propose a planar elastic tube bundle heat transfer element that utilizes fluid-induced tube bundle vibration for enhanced heat transfer. This tube bundle has two fixed ends and one floating mass end. Chinese invention patent "Spatial Helical Elastic Enhanced Heat Exchange Tube Bundle and Its Support Device" (application number: 200810015875.3) proposes a spatial helical elastic enhanced heat exchange tube bundle, which is divided into single-helix and double-helix types. The double-helix type heat exchange tube has a floating mass block. The working principle of the above inventions is that the shell-side fluid sweeps across the heat exchange tube bundle, utilizing different fluid media and different fluid flow velocities to induce the heat transfer element to achieve the required vibration, thus meeting the design requirements for different vibration modes of the heat exchange tube bundle. The floating mass block is the main component of fluid-induced heat exchanger tube vibration and is an important part affecting the mode shape, frequency and amplitude of the heat exchanger tube bundle.

[0006] In traditional shell-and-tube heat exchangers with baffles, the tube bundles are typically supported by arc-shaped baffles, which are made of steel or stainless steel. Traditional heat exchangers all incorporate baffles, such as arc-shaped baffles, to prevent fluid short-circuiting and thus enhance heat transfer. However, while using arc-shaped baffles alone can enhance heat transfer to some extent, further improvements can be made to achieve even greater heat transfer enhancement.

[0007] This invention innovatively incorporates arc-shaped tubes into the deflector plate and improves the distribution of these arc-shaped tubes, thereby specifically increasing the convective heat transfer coefficient and effectively improving heat transfer efficiency. Summary of the Invention

[0008] To overcome the defects and shortcomings of the existing technology, the present invention provides a shell-and-tube heat exchanger with an elastic tube bundle baffle. The baffle is equipped with arc-shaped tubes, and the distribution of the number of arc-shaped tubes is improved. The baffle is set as an elastic tube bundle structure. Through the above structure, the contact area between the two fluids is increased, the heat exchange area is increased, and the convective heat transfer coefficient of the shell side of the heat exchanger can be improved, thereby effectively improving the heat transfer efficiency.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows: A shell-and-tube heat exchanger with varying numbers of curved tubes in the baffle plate, wherein baffle plates are disposed inside the shell of the shell-and-tube heat exchanger, and heat exchange tubes pass through the baffle plates; characterized in that the baffle plates comprise multiple curved tubes, the heat exchange fluids in the tube side and shell side flow counter-currently, and along the flow direction of the fluid in the tube side, the number of curved tubes in the baffle plate continuously decreases from the tube side inlet to the middle position of the tube side, and then continuously increases from the middle position of the tube side to the tube side outlet.

[0010] As an improvement, along the flow direction of the fluid in the tube, from the tube inlet to the middle of the tube, the rate at which the number of arc-shaped tubes of the baffle decreases continuously increases, and then from the middle of the tube to the tube outlet, the rate at which the number of arc-shaped tubes of the baffle increases continuously decreases.

[0011] As an improvement, it includes a shell and tube, heat exchange tubes, tube-side inlet tubes, tube-side outlet tubes, shell-side inlet pipes, and shell-side outlet pipes; a heat exchange tube bundle composed of multiple parallel heat exchange tubes is connected to the front tube sheet and the rear tube sheet; the front end of the front tube sheet is connected to the front end cap, and the rear end of the rear tube sheet is connected to the rear end cap.

[0012] As an improvement, the baffle is an elastic tube bundle structure, including an elastic tube bundle, which includes multiple arc-shaped tubes. The center lines of the multiple arc-shaped tubes are concentric arcs, the outermost arc-shaped tube has an outer open end, and the innermost arc-shaped tube has an inner open end.

[0013] As an improvement, the end of the middle arc-shaped tube forms a connecting end with an adjacent arc-shaped tube at one end, while the other end is not connected. The end of the middle arc-shaped tube forms a connecting end with another adjacent arc-shaped tube at one end, while the other end forms a connecting end. Thus, one end of the connecting end forms a free end, and the elastic tube bundle forms a series structure from the outer opening end to the inner opening end.

[0014] As an improvement, each heat exchange tube is divided into multiple sections, including a side heat exchange tube section and a middle heat exchange tube section. One end of the side heat exchange tube section is connected to the front tube sheet or the rear tube sheet to communicate with the front end and the rear end, and the other end is connected to the arc-shaped tube in the baffle. The two ends of the middle heat exchange tube section are respectively connected to the arc-shaped tube of the adjacent baffle.

[0015] As an improvement, the heat exchange tube includes an outer tube and an inner tube, and the outer open end and the inner open end of the elastic tube bundle are respectively connected to the outer tube and the inner tube.

[0016] Compared with the prior art, the present invention has the following advantages: This invention changes the heat exchange area between the tube-side fluid and the shell-side fluid by varying the number of arc-shaped tubes. The heat exchange area increases and decreases with the increase and decrease of the volume. Therefore, the unevenness of heat exchange is compensated by the change in area, thereby further improving the heat exchange efficiency.

[0017] 2) This invention innovatively replaces the baffle with an elastic tube bundle structure, increasing the free end of the elastic tube bundle. This allows for increased fluid turbulence during fluid impact within the tube side, enhancing heat transfer and achieving descaling. Simultaneously, the fluid within the tube side can flow inside the elastic tube bundle, further impacting and vibrating the free end, thus enhancing heat transfer and descaling. Moreover, the aforementioned structure allows the baffle to be filled with tube-side fluid, increasing the heat exchange area between the tube-side and shell-side fluids and further enhancing heat transfer.

[0018] 3) By changing the spacing of the arc tubes in the radial direction of the baffle, the fluid on the outside can flow as close to the middle as possible, further reducing fluid short-circuiting. At the same time, because the free ends of the elastic tube bundle are all in the center, the fluid can scour the free ends as much as possible, thereby enhancing heat transfer.

[0019] 4) By varying the density of the distance between the heat exchange tube and the arc-shaped tube connection, the free end of the connection can vibrate freely as much as possible, thereby enhancing heat transfer.

[0020] 5) The number of arc-shaped tubes with baffles changes continuously with the fluid flow in the tube, further enhancing heat transfer and improving the overall heat exchange efficiency.

[0021] 6) Periodically change the fluid flow rate of the upper and lower end caps to cause frequent vibrations at the free end of the elastic tube bundle of the baffle, thereby further achieving descaling and enhancing heat transfer. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a shell-and-tube heat exchanger in the prior art; Figure 2 This is a schematic diagram of the heat exchange tube structure of the shell-and-tube heat exchanger with hollow cavity baffles according to the present invention. Figure 3 This is a front view of the elastic tube bundle baffle of the present invention; Figure 4 This is a front view of the elastic tube bundle baffle plate with heat exchange tubes in this invention; Figure 5 This is a schematic diagram of the connection between the heat exchange tube and the arc tube of the present invention; Figure 6 This is a schematic diagram of the shell-and-tube heat exchanger with upper and lower end caps according to the present invention. Detailed Implementation

[0023] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] Unless otherwise specified, in this article, " / " represents division, and "×" and "*" represent multiplication.

[0025] It should be noted that, unless otherwise specified, the two-phase flow mentioned in this invention is a gas-liquid two-phase flow, where the gas is an insoluble or sparingly soluble gas, meaning that the gas will not dissolve in the liquid during the heat exchange process.

[0026] Figure 1 The diagram shows a shell-and-tube heat exchanger in the prior art. The shell-and-tube heat exchanger includes a shell 1, heat exchange tubes 8, tube-side inlet tubes 9, tube-side outlet tubes 10, shell-side inlet pipe 2, and shell-side outlet pipe 3. A heat exchange tube bundle consisting of multiple parallel heat exchange tubes 8 is connected to a front tube sheet 6 and a rear tube sheet 7. The front end of the front tube sheet 6 is connected to a front end cap 4, and the rear end of the rear tube sheet 7 is connected to a rear end cap 5. The tube-side outlet tube 10 is disposed on the rear end cap 5. The tube-side inlet tube 9 is disposed on the front end cap 4. The shell-side inlet pipe 2 and shell-side outlet pipe 3 are both disposed on the shell 4. The tube-side fluid enters through the tube-side inlet tube 9, exchanges heat with the shell-side fluid through the heat exchange tubes, and exits through the tube-side outlet tube 10.

[0027] Figure 2 This invention demonstrates that... Figure 1 A shell-and-tube heat exchanger with an improved flexible tube bundle structure baffle plate based on the existing design. For example... Figure 2 As shown, the shell-and-tube heat exchanger includes a shell 1, heat exchange tubes 8, tube-side inlet tubes 9, tube-side outlet tubes 10, shell-side inlet pipe 2, and shell-side outlet pipe 3; a heat exchange tube bundle consisting of multiple parallel heat exchange tubes 8 is connected to a front tube sheet 6 and a rear tube sheet 7; the front end of the front tube sheet is connected to a front end cap 4, and the rear end of the rear tube sheet is connected to a rear end cap 5; a baffle plate 11 is provided inside the shell, and the heat exchange tubes 8 pass through the baffle plate 11; the remaining undescribed structures are similar to... Figure 1 same.

[0028] Compared to Figure 1 Improvements to heat exchangers, such as Figure 2-4 As shown, the baffle 11 is an elastic tube bundle structure, comprising an elastic tube bundle. Figure 3 , 4 As shown, the elastic tube bundle includes multiple arc-shaped tubes 111, with the centerlines of the multiple arc-shaped tubes forming concentric circular arcs. The outermost arc-shaped tube 1111 has an outer open end 113, and the innermost arc-shaped tube 1112 has an inner open end 114. The middle arc-shaped tube 1113 is adjacent to the inner and outer arc-shaped tubes. The end of the middle arc-shaped tube forms a connecting end 112 with one of the adjacent arc-shaped tubes at one end, but not at the other end. The end of the middle arc-shaped tube does not connect with another adjacent arc-shaped tube at one end, but forms a connecting end 112 at the other end, thus forming a free end at one end of the connecting end. The elastic tube bundle forms a series structure from the outer open end 113 to the inner open end 114. For example... Figure 4The middle arc-shaped tube, indicated by reference numeral 1113 in the attached diagram, forms a connection with the outer arc-shaped tube at one end on the right side but not on the left side, and with the inner arc-shaped tube at one end on the left side but not on the right side. This represents a series connection between the arc-shaped tubes from the outer open end 113 to the inner open end 114.

[0029] The baffle 11 is an elastic tube bundle structure, and each heat exchange tube is divided into multiple segments, including edge heat exchange tube segments 81 and 82 and middle heat exchange tube segment 83. Figure 2 As shown, the front end of the edge heat exchange tube section 81 is connected to the front tube sheet 6, and is connected to the front end cap 4 through the front tube sheet 6. The rear end is connected to the arc-shaped tube 111 of the adjacent baffle 11. The rear end of the edge heat exchange tube section 82 is connected to the rear tube sheet 7, and is connected to the rear end cap 5 through the rear tube sheet 7. The front end of the rear tube sheet is connected to the arc-shaped tube 111 of the adjacent baffle 11. The two ends of the middle heat exchange tube section 83 are respectively connected to the arc-shaped tube 111 of the adjacent baffle, as shown. Figure 5 As shown. The heat exchange tube includes an outer tube 84 and an inner tube 85, and the outer opening end 113 and the inner opening end 114 of the elastic tube bundle are respectively connected to the outer tube 84 and the inner tube 85.

[0030] This invention innovatively replaces the baffle with an elastic tube bundle structure, increasing the free end of the elastic tube bundle. This increases fluid turbulence during fluid impact within the tubes, enhancing heat transfer and achieving descaling. Simultaneously, the fluid within the tubes can flow inside the elastic tube bundle, further impacting and vibrating the free end, thus enhancing heat transfer and descaling. Furthermore, this structure allows the baffle to be filled with tube-side fluid, increasing the heat exchange area between the tube-side and shell-side fluids, further enhancing heat transfer. At the same time, the elastic tube bundle structure of this invention increases the flow space within the tubes, further reducing flow resistance.

[0031] As an improvement, such as Figure 2 As shown, the heat exchanger also includes a support structure 12, which connects the inner wall of the shell side 1 and the outermost arc-shaped tube 1111, and is used to support the baffle plate.

[0032] As an improvement, support structure 122 is a support plate used to form a closed structure between the inner wall of the shell side and the outermost arcuate tube. By forming a closed structure, fluid is prevented from flowing through the top or bottom, reducing short circuits.

[0033] As an improvement, such as Figure 3-4 As shown, the connecting end 112 of the adjacent arc-shaped tubes 111 is located at the center of the tube shell. For example, it is located on the center surface in the vertical direction of the tube shell. Because the volume of fluid flowing through the center is the largest, by setting it on the center surface, the fluid can be flushed across the free end as much as possible, thereby enhancing heat transfer.

[0034] As an improvement, the spacing between adjacent arc-shaped tubes 111 decreases from the center of the tube shell 1 to the inner wall of the tube shell, that is, along the radial direction of the baffle 11. By changing the spacing between the arc-shaped tubes in the radial direction of the baffle, the fluid on the outside can flow as close to the center as possible, further reducing fluid short-circuiting. At the same time, because the free ends of the elastic tube bundle are all in the center, the fluid can scour the free ends as much as possible, thereby enhancing heat transfer.

[0035] As an improvement, the spacing between adjacent arc-shaped tubes 111 gradually decreases from the center of the tube shell 1 to the inner wall of the tube shell. This structure further enhances heat transfer and achieves better heat exchange performance.

[0036] As an improvement, the distribution density of heat exchange tubes 8 increases with distance from the connection point of adjacent arc-shaped tubes. This density variation in the distance between the heat exchange tubes and the arc-shaped tube connection allows the free end of the connection to vibrate freely, thus enhancing heat transfer.

[0037] As an improvement, the distribution density of heat exchange tubes increases progressively with increasing distance from the connection point of adjacent arc-shaped tubes. This variation in density based on the distance of the heat exchange tubes from the arc-shaped tube connection point further allows the free end of the connection point to vibrate freely, enhancing heat transfer.

[0038] As an improvement, the diameters of the outer tube 84 and the inner tube 85 are larger than those of the other heat exchange tubes. This arrangement allows the outer and inner tubes to act as an end structure, handling more fluid distribution. This enables a large amount of fluid to enter the middle elastic free end through the outermost and innermost arc-shaped tubes, thereby increasing the frequency of elastic vibration, improving the heat transfer coefficient, and enhancing the descaling capacity.

[0039] As an improvement, the shell-and-tube heat exchanger is a horizontal shell-and-tube heat exchanger, and the baffles 11 are arranged vertically.

[0040] As a preferred option, such as Figure 3 As shown, the elastic tube bundle structure is a semi-circular structure.

[0041] As an improvement, the heat exchange fluids in the tube side and shell side flow counter-currently. Along the flow direction of the fluid within the tube side, the number of curved tubes in the baffle plate continuously decreases from the tube inlet to the middle of the tube side, and then continuously increases from the middle of the tube side to the tube outlet. Because the heat exchange per unit length along the fluid flow path is relatively uniform during counter-current flow, the overall heat exchange effect is optimal. However, experiments and simulations have shown that the heat exchange in the middle is significantly greater than that at the tube inlet and outlet. Therefore, by varying the number of curved tubes, the heat exchange area between the tube-side fluid and the shell-side fluid also changes. This heat exchange area increases and decreases with increasing and decreasing volume, thus compensating for the uneven heat exchange by changing the area, thereby further improving heat exchange efficiency.

[0042] As an improvement, along the flow direction of the fluid within the tube, the rate at which the number of curved tubes in the baffle decreases gradually increases from the tube inlet to the middle of the tube, and then the rate at which the number of curved tubes in the baffle increases gradually decreases from the middle of the tube to the tube outlet. These variations in rate of increase make the heat transfer per unit length of the entire fluid flow more uniform, further improving heat transfer efficiency.

[0043] As an improvement, the shell-and-tube heat exchanger is a horizontal shell-and-tube heat exchanger, and the baffles are arranged vertically.

[0044] As an improvement, the spacing between the baffles 11 decreases continuously from the tube inlet to the middle of the tube along the flow direction of the fluid. Then, the spacing between the baffles 11 increases continuously from the middle of the tube to the tube outlet.

[0045] As an improvement, along the flow direction of the fluid within the tube, the rate at which the spacing between the baffles 11 decreases continuously increases from the tube inlet to the middle of the tube. Then, from the middle of the tube to the tube outlet, the rate at which the spacing between the baffles 11 increases continuously decreases.

[0046] The technical effects of the aforementioned changes in the number of baffles are described in the previous section on the technical effects of changes in the volume of baffles.

[0047] As an improvement, such as Figure 6As shown, the inlet end cap 4 is divided into upper and lower parts 41 and 42 by a partition 12. The upper heat exchange tube 111 is connected to the upper end cap 41, and the lower heat exchange tube 112 is connected to the lower end cap 42. The upper end cap 41 and the lower end cap 42 are respectively provided with an upper inlet 91 and a lower inlet 92. The fluid flow rates of the upper inlet 91 and the lower inlet 92 can be controlled independently, preferably by a controller. As an improvement, the fluid flow rates of the upper end cap 41 and the lower end cap 42 are different, thereby resulting in different fluid flow rates entering the upper heat exchange tube 111 and the lower heat exchange tube 112.

[0048] By setting upper and lower end caps, the fluid flow rates at the upper and lower end caps are different, which can make the flow rates at different positions inside the arc-shaped tube different. This causes the free end to vibrate frequently due to the different flow rates, further enhancing heat transfer.

[0049] As an improvement, within a cycle T, from 0 to T / 2, the flow rate of the upper end cap is V1, and the flow rate of the lower end cap is V2, where V1 is greater than V2. This results in a higher fluid velocity in the upper heat exchange tube than in the lower heat exchange tube. From T / 2 to T, the flow rate of the lower end cap is V1, and the flow rate of the upper end cap is V2. This again results in a higher fluid velocity in the lower heat exchange tube than in the upper heat exchange tube. Periodically changing the fluid flow rates of the upper and lower end caps causes the fluid in the arc-shaped tube of the baffle to change its circulating flow direction. This causes the free end to vibrate frequently due to the different fluid movement directions. The periodic change in the impact direction of the circulating disturbance further enhances heat transfer.

[0050] Preferably, the period T can be 30-50 minutes.

[0051] As a preferred option, V1 is 3-5 times that of V2.

[0052] As an improvement, the fluid entering the upper and lower end caps is a pulsating flow with constantly changing velocity. The pulsating flow continuously changes the direction of the circulating flow of the fluid inside the arc-shaped pipe, thereby causing the free end to vibrate frequently due to the different directions of fluid movement.

[0053] Preferably, within a period T, from 0 to T / 2, the flow velocity in the upper head continuously increases from 0 to V, while the velocity in the lower head continuously decreases from V to 0; from T / 2 to T, the flow velocity in the lower head continuously increases from 0 to V, while the velocity in the upper head continuously decreases from V to 0. This continuous change in fluid velocity between the upper and lower heads causes a constant change in the direction of fluid disturbance, promoting further heat transfer.

[0054] As an improvement, the tube-side inlet pipe is located on the rear end cap; the tube-side outlet pipe is located on the front end cap; both the shell-side inlet pipe and the shell-side outlet pipe are located on the shell, and the heat exchange tubes are arc-shaped tubes connected to the baffle 11 by welding.

[0055] While the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A shell-and-tube heat exchanger with varying numbers of baffled arc-shaped tubes, the shell-and-tube heat exchanger comprising a shell, heat exchange tubes, tube-side inlet tubes, tube-side outlet tubes, shell-side inlet nozzles, and shell-side outlet nozzles; a heat exchange tube bundle consisting of multiple parallel heat exchange tubes connected to a front tube sheet and a rear tube sheet; the front end of the front tube sheet connected to a front end cap, and the rear end of the rear tube sheet connected to a rear end cap; baffles are disposed within the shell of the shell-and-tube heat exchanger, and the heat exchange tubes pass through the baffles; characterized in that, The baffle is an elastic tube bundle structure, comprising multiple arc-shaped tubes. The centerlines of the multiple arc-shaped tubes are concentric circular arcs. The outermost arc-shaped tube has an outer open end, and the innermost arc-shaped tube has an inner open end. The end of the middle arc-shaped tube forms a connection with an adjacent arc-shaped tube at one end, but not at the other end. The end of the middle arc-shaped tube forms a connection with another adjacent arc-shaped tube at one end, but not at the other end, thus forming a free end at one end of the connection end. The elastic tube bundle forms a series structure from the outer open end to the inner open end. The heat exchange fluid in the tube side and shell side flows counter-currently. Along the flow direction of the fluid in the tube side, from the tube side inlet to the middle position of the tube side, the number of arc-shaped tubes in the baffle continuously decreases, and then from the middle position of the tube side to the tube side outlet, the number of arc-shaped tubes in the baffle continuously increases.

2. The shell-and-tube heat exchanger as described in claim 1, characterized in that, Along the flow direction of the fluid in the tube, from the tube inlet to the middle of the tube, the rate at which the number of arc-shaped tubes of the baffle plate decreases continuously increases, and then from the middle of the tube to the tube outlet, the rate at which the number of arc-shaped tubes of the baffle plate increases continuously decreases.

3. The shell-and-tube heat exchanger as described in claim 1, characterized in that, Each heat exchange tube is divided into multiple sections, including a side heat exchange tube section and a middle heat exchange tube section. One end of the side heat exchange tube section is connected to the front tube sheet or the rear tube sheet to communicate with the front head and the rear head, and the other end is connected to the arc-shaped tube in the baffle. The two ends of the middle heat exchange tube section are respectively connected to the arc-shaped tubes of the adjacent baffle.

4. The shell-and-tube heat exchanger as described in claim 3, characterized in that, The heat exchange tube includes an outer tube and an inner tube, and the outer open end and the inner open end of the elastic tube bundle are respectively connected to the outer tube and the inner tube.

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