U-shaped tube heat exchanger with U-shaped shell

Abstract

The invention discloses a U-shaped tube heat exchanger with a U-shaped shell. The U-shaped tube heat exchanger comprises a U-shaped heat exchange tube, the U-shaped shell and two tube plate header assemblies. The U-shaped heat exchange tube is arranged in the U-shaped shell, the space trend of the U-shaped heat exchange tube in the U-shaped shell is matched with the outline of an inner cavity of the U-shaped shell, the two opening ends of the U-shaped shell are welded to the two tube plate header combination bodies in one-to-one correspondence, and compared with the prior art, by arranging the tube core space, the inner space of the U-shaped heat exchange tube is fully utilized. Meanwhile, due to the design of the fin bodies, the tube pass heat exchange area is further increased on the basis of the original primary heat exchange area, and the secondary heat exchange area is further increased. The long fins and the middle fins are designed in different heights, so that the total heat exchange area obviously exceeds the inner wall of a single light pipe, and the heat exchange efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and in particular to a U-tube heat exchanger with a U-shaped shell. Background Art

[0002] U-tube heat exchangers are widely used in the chemical, energy, and other fields due to their compact structure and strong thermal compensation capabilities. Conventional U-tube heat exchangers use a straight cylindrical shell, with the inlet and outlet of the hot and cold fluids arranged on the same tube sheet.

[0003] However, in actual operation, this structure still has the following deficiencies: Currently, most U-shaped heat exchange tubes in existing technology use bare tubes for heat exchange. This results in low heat exchange efficiency due to the limited heat exchange area on the inner surface of the tube. Furthermore, the hot and cold inlets and outlets of the tube side media are located in adjacent areas of the same tube sheet, resulting in a large temperature difference on both sides of the interface and significant thermal stress, which can shorten the lifespan and even damage the equipment.

[0004] Therefore, how to solve the above-mentioned deficiencies in the prior art has become the subject to be studied and solved by the present invention. Summary of the Invention

[0005] The present invention provides a U-tube heat exchanger with a U-shaped shell, aiming to solve the technical problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a U-tube heat exchanger with a U-shaped shell, comprising a U-shaped heat exchange tube, a U-shaped shell and a two-tube sheet header assembly; a U-shaped heat exchange tube is arranged in the U-shaped shell, and the spatial direction of the U-shaped heat exchange tube in the U-shaped shell matches the inner cavity contour of the U-shaped shell, the two open ends of the U-shaped shell are welded to the two corresponding tube sheet header assemblies, and the two end heads of the U-shaped heat exchange tube are respectively connected to the corresponding tube holes on the tube sheet header assembly; it also includes a fin structure arranged in the U-shaped heat exchange tube, the fin structure is uniformly distributed along the circumferential direction of the inner wall of the U-shaped heat exchange tube, and the fin structure includes a plurality of fin bodies distributed on the circumferential inner wall of the U-shaped heat exchange tube, and the fin bodies are arranged at intervals so that the inner cavity of the U-shaped heat exchange tube The U-shaped heat exchange tube is divided into multiple medium flow channels; each fin body has a root portion fixedly connected to the inner wall of the U-shaped heat exchange tube and a tip end extending toward the center of the U-shaped heat exchange tube; on any cross section perpendicular to the axis of the U-shaped heat exchange tube, the fin body includes multiple long wing portions and middle wing portions in the same plane; the long wing portions are spaced apart on the circumferential inner wall of the U-shaped heat exchange tube, and the middle wing portions are spaced apart between adjacent long wing portions; the tips of all long wing portions gather at the center of the U-shaped heat exchange tube, and the tips of the long wing portions are in contact or non-contact with each other, defining a tube core space at the center of the U-shaped heat exchange tube; the length of the middle wing portion on the cross section of the U-shaped heat exchange tube is less than the length of the long wing portion; the diameter of the tube core space is less than or equal to the spacing between the roots of adjacent fin bodies.

[0007] The relevant contents of the above plan are explained as follows: In the above scheme, unlike the straight cylindrical shell in the prior art, which forms a significant temperature difference on both sides of the tube sheet, the present application adopts two independent tube sheet header assemblies to separate the cold end and the hot end. This not only avoids the disadvantage of the ordinary U-tube heat exchanger in which the cold and hot fluids form a significant temperature difference on both sides of the same tube sheet, but also avoids the problem of the ordinary shell and tube heat exchanger shell and the U-shaped heat exchange tube expansion being difficult to coordinate.

[0008] In the above solution, the two tube sheet header assemblies are connected to the two ends of the U-shaped heat exchange tube in a one-to-one correspondence, which means that the two ends of the U-shaped heat exchange tube are respectively inserted into the two tube sheet header assemblies. At the same time, the second medium flowing in the U-shaped heat exchange tube will not penetrate into the first medium flow channel from the tube sheet header assemblies.

[0009] In the above solution, the fin body can be straight, porous, serrated, etc.

[0010] In the above solution, the existence of the tube core space is also to further increase the heat exchange area.

[0011] Unlike existing technologies, this application fully utilizes the internal space of the U-shaped heat exchange tube by providing a core space. The fin design increases the secondary heat exchange area of ​​the tube side, in addition to the existing primary heat exchange area. The long and middle fins are designed with different heights, resulting in a total heat exchange area that significantly exceeds the inner wall area of ​​a single bare tube by several times, for example, double or triple. The more fin types there are, the higher the heat exchange efficiency.

[0012] A further technical solution is that on any cross section perpendicular to the axis of the U-shaped heat exchange tube, the fin body also includes a plurality of short wing portions; the length of the short wing portion on the cross section of the U-shaped heat exchange tube is greater than or equal to half the length of the long wing portion; the short wing portion is spaced between adjacent long wing portions and middle wing portions.

[0013] A further technical solution is that the fin body has multiple sections and is spliced ​​in sequence along the axial direction of the U-shaped heat exchange tube. Each section is made by rolling or stamping on the same plate, and is made into an approximately cylindrical shape through a rolling process and then embedded in the U-shaped heat exchange tube, and is welded and fixed between the root of the fin body and the inner wall of the U-shaped heat exchange tube.

[0014] With the aid of the above design, the long wing portion, the middle wing portion and the short wing portion can be made stronger and less abrasive, and it is more convenient to subsequently form them into a cylindrical shape.

[0015] A further technical solution is that a separation space is set between the two tube sheet header assemblies; the U-shaped shell is provided with a medium inlet and a medium outlet connected to the inner cavity of the U-shaped shell, and a first medium flow channel is formed through the medium inlet, the space between the inner wall of the U-shaped shell and the outer wall of the U-shaped heat exchange tube to the medium outlet; the two tube sheet header assemblies are provided with a second medium inlet on one and a second medium outlet on the other, and a second medium flow channel is formed through the second medium inlet, the tube sheet header assembly corresponding to the second medium inlet, the inner cavity of the U-shaped heat exchange tube, the tube sheet header assembly corresponding to the second medium outlet to the second medium outlet.

[0016] In the above solution, the first medium (water or steam) flows through the first medium flow channel, and the second medium (water or steam) flows through the second medium flow channel, and the two media will not mix.

[0017] In the above scheme, the disadvantage of a conventional U-tube heat exchanger in which a significant temperature difference is formed between the hot and cold fluids on both sides of the same tube sheet can be avoided by cooperating with the U-shaped shell and the two tube sheet header assemblies. Specifically, the two open ends of the U-shaped shell are directly guided to be sealed and connected to the two tube sheet header assemblies in a one-to-one correspondence. In this way, the first medium will flow in the first medium flow channel, and the second medium will flow in the second medium flow channel. Since there is a gap between the two open ends of the U-shaped shell, the heat between the two tube sheet header assemblies can be separated.

[0018] A further technical solution is that the tube sheet and header assembly consists of a tube sheet and a header, and the header includes a flange, a head and a connecting pipe; one side of the tube sheet is sealed and connected to the open end of the U-shaped shell, and the other side is fastened to the flange of the header through a gasket and bolts; the side of the flange away from the tube sheet is sealed and welded to the head, and the end face of the tube sheet and the inner wall of the head jointly define a convergence chamber for collecting or distributing the second medium; the connecting pipe is connected to the head, and the pipe mouth of the connecting pipe serves as the second medium inlet or the second medium outlet; the end of the U-shaped heat exchange tube passes through the tube sheet and is sealed and connected to it, and is connected to the convergence chamber.

[0019] With the above design, the tube sheet header assembly can simultaneously achieve the purpose of sealing the open end of the U-shaped shell and guiding the medium to flow in the second medium flow channel.

[0020] Specifically, one side of the tube sheet structure is sealed to the open end of the U-shaped shell, and the other side is sealed to the flange plate (the connection method is bolt connection). Then, the end of the U-shaped heat exchange tube is guided through the tube sheet structure and sealed to it, and then extended into the converging chamber. At this time, the medium inlet and medium outlet on the peripheral surface of the U-shaped shell and the inner cavity of the U-shaped shell sealed by the two tube sheet header assemblies constitute a first medium flow channel. That is, the first medium will flow in the first medium flow channel, and at the same time, the second medium is guided into one of the converging chambers, so that the second medium will flow in the second medium flow channel and then be discharged from the other converging chamber.

[0021] A further technical solution is that the tube sheet includes a tube sheet body, a thermal insulation gasket and a pressure plate arranged in sequence from the outside of the shell to the inside of the shell along the axial direction at the open end of the U-shaped shell; the tube sheet body has a relative inner surface and an outer surface; the thermal insulation gasket and the pressure plate are both located inside the U-shaped shell, and the thermal insulation gasket is arranged close to the tube sheet body; the thermal insulation gasket is used to reduce the heat of the first medium transferred to the tube sheet body.

[0022] In the above solution, the U-shaped heat exchange tube passes through the pressing plate and the insulating gasket (sealing can be achieved by expansion, welding or sealing gaskets), and then extends into the converging chamber.

[0023] With the above design, the tube sheet structure can simultaneously isolate the temperatures of both sides of the tube sheet structure, that is, the front and back surfaces, and can also prevent the generation of a large temperature around the open end of the U-shaped shell. Specifically, because the insulating gasket is located inside the open end of the U-shaped shell and is arranged in close proximity to the front surface of the tube sheet body, the temperature of the first medium flowing in the first medium flow channel will not be transferred to the back surface in large quantities. At the same time, because the insulating gasket and the interior of the U-shaped shell have an overfitting or interference fit, the heat transferred from the second medium to the tube sheet body will not be transferred to the side around the open end of the U-shaped shell.

[0024] The insulating gasket is made of thermal insulation materials such as polymer-based composite materials. Its thermal insulation effect greatly reduces the temperature difference between the two sides of the tube sheet body, that is, reduces the temperature difference thermal stress on the two sides of the tube sheet body. At the same time, it also reduces the risk of structural failure caused by stress corrosion and stress cracking of the tube sheet, thereby extending the service life of the equipment.

[0025] According to a further technical solution, a plurality of U-shaped heat exchange tubes are provided, and the plurality of U-shaped heat exchange tubes are combined to form a tube bundle structure through baffles provided in the U-shaped shell.

[0026] With the above design, the heat exchange between the first medium and the second medium is more complete.

[0027] According to a further technical solution, the thermal insulation gasket is provided with a through hole for guiding the U-shaped heat exchange tube into the converging chamber.

[0028] With the above design, the U-shaped heat exchange tube can be extended to the converging chamber through the through hole. Furthermore, a sealing member or other structure can be provided at the end of the through hole to achieve sealing.

[0029] It should be noted that the through holes are the corresponding tube holes on the aforementioned tube sheet header assembly. The through holes are set on the entire tube sheet.

[0030] A further technical solution is to provide a plurality of baffles in the U-shaped shell, and all the baffles are arranged in a direction perpendicular to the axis of the U-shaped heat exchange tube and in an inverse order.

[0031] With the above design, when the first medium flows in the space between the inner wall of the U-shaped shell and the outer wall of the U-shaped heat exchange tube, it can be blocked and limited by the baffle, so that the flow path of the first medium in the space is lengthened, thereby improving the heat exchange efficiency.

[0032] That is, the baffles force the first medium to flush the U-shaped heat exchange tubes horizontally to improve the heat exchange efficiency.

[0033] The reverse order means that the baffles use a circular structure with flat notches. For example, when arranging the baffles, the notches of adjacent baffles are arranged to face the inside (positive order) and outside (negative order) of the U-shaped heat exchange tube, respectively, to guide the flow of the first medium.

[0034] The terms “first”, “second”, etc. used in this document do not specifically refer to an order or sequence, nor are they used to limit this case. They are only used to distinguish components or operations described with the same technical terms.

[0035] As used herein, “connected” or “positioned” may refer to two or more components or devices being in direct or indirect physical contact with each other, or may refer to two or more components or devices operating or moving with each other.

[0036] The terms “include”, “including”, “have”, etc. used in this document are open-ended terms, meaning including but not limited to.

[0037] Unless otherwise noted, the terms used herein generally have their ordinary meanings in the art, in the context of this application, and in the specific context. Certain terms used to describe this application are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art regarding the description of this application.

[0038] The terms "front", "back", "up", "down", "left", "right", etc. used in this article are all directional terms. In this case, they are only used to illustrate the positional relationship between the various structures, and are not used to limit the protection plan of this case and the specific direction during actual implementation.

[0039] The working principle and advantages of the present invention are as follows: The present invention is different from the straight cylindrical shell in the prior art, which forms a significant temperature difference on both sides of the tube sheet. The present application adopts two independent tube sheet header assemblies to separate the cold end and the hot end, which not only avoids the disadvantage of the ordinary U-tube heat exchanger in which the cold and hot fluids form a significant temperature difference on both sides of the same tube sheet, but also avoids the problem of the ordinary shell and tube heat exchanger shell and the U-shaped heat exchange tube expansion being difficult to coordinate.

[0040] This invention differs from existing technologies by providing a core space to fully utilize the interior space of the U-shaped heat exchange tube. Furthermore, the fin design increases the secondary heat exchange area on top of the existing primary heat exchange area. Specifically, the long and medium fins are designed at different heights, resulting in a total heat exchange area exceeding that of a single bare tube wall, thus improving heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Attachment Figure 1 Schematic diagram of the overall structure of an embodiment of the present invention; Attachment Figure 2 Schematic diagram of the structure of the tube sheet header assembly in an embodiment of the present invention; Attachment Figure 3 Schematic diagram of the baffle structure in an embodiment of the present invention; Attachment Figure 4 This is a schematic cross-sectional view of a U-shaped heat exchange tube of a first embodiment of a fin body in an embodiment of the present invention; Attachment Figure 5 This is a schematic cross-sectional view of a U-shaped heat exchange tube of a second embodiment of a fin body in an embodiment of the present invention; Attachment Figure 6 This is a schematic structural diagram of a fin body in an embodiment of the present invention after being formed into a substantially cylindrical shape through a rolling process; Attachment Figure 7 Schematic diagram of the flow path of fluid in a U-shaped heat exchange tube in the prior art (a core tube is provided in the U-shaped heat exchange tube); Attachment Figure 8 This is a schematic cross-sectional view of a U-shaped heat exchange tube of a third embodiment of a fin body in an embodiment of the present invention; Attachment Figure 9 This is a schematic diagram of a state in which the fin body in an embodiment of the present invention is formed by rolling or stamping a plate and is not subjected to a rounding process to be made into a nearly cylindrical shape.

[0042] In the above figures: 1. U-shaped heat exchange tube; 2. U-shaped shell; 3. Medium inlet; 4. Medium outlet; 5. Header; 6. Tube sheet; 7. Flange; 8. Header; 9. Converging chamber; 10. Tube sheet body; 11. Thermal insulation gasket; 12. Pressure plate; 13. Tube bundle structure; 14. Through hole; 15. Baffle; 16. Second medium inlet; 17. Second medium outlet; 18. Connecting pipe; 19. Tube sheet and header assembly; 20. Fin body; 21. Long fin portion; 22. Middle fin portion; 23. Short fin portion; 24. Tube core space; 25. Root portion; 26. Tip; 27. Medium flow channel; R1, the diameter of the tube core space; H1, the distance between the roots of adjacent fin bodies. DETAILED DESCRIPTION

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments: Embodiment: The present invention will be clearly illustrated below with drawings and detailed descriptions. After understanding the embodiments of the present invention, any person skilled in the art can make changes and modifications based on the techniques taught by the present invention without departing from the spirit and scope of the present invention.

[0044] The terms used herein are for describing specific embodiments only and are not intended to be limiting of the present invention. Singular forms such as "a," "the," "this," "this," and "the" as used herein also include plural forms.

[0045] See attached Figures 1-9As shown, a U-tube heat exchanger with a U-shaped shell 2 includes a U-shaped heat exchange tube 1, a U-shaped shell 2 and two tube sheet header assemblies 19; the U-shaped heat exchange tube 1 is arranged in the U-shaped shell 2, and the spatial direction of the U-shaped heat exchange tube 1 in the U-shaped shell 2 matches the inner cavity contour of the U-shaped shell 2, the two open ends of the U-shaped shell 2 are welded to the two tube sheet header assemblies 19 corresponding to each other, and the two end heads of the U-shaped heat exchange tube 1 are respectively connected to the corresponding tube holes on the tube sheet header assemblies 19; it also includes a fin structure arranged in the U-shaped heat exchange tube 1, the fin structure is uniformly distributed along the circumferential direction of the inner wall of the U-shaped heat exchange tube 1, and the fin structure includes a plurality of fin bodies 20 distributed on the circumferential inner wall of the U-shaped heat exchange tube 1, and the fin bodies 20 are arranged at intervals so that the interior of the U-shaped heat exchange tube 1 is divided into a plurality of medium flow channels 27; each fin body 20 has It has a root portion 25 fixedly connected to the inner wall of the U-shaped heat exchange tube 1 and a tip end 26 extending toward the center of the U-shaped heat exchange tube 1; on any cross section perpendicular to the axis of the U-shaped heat exchange tube 1, the fin body 20 includes a plurality of long wing portions 21 and middle wing portions 22 in the same plane; the long wing portions 21 are spaced apart on the circumferential inner wall of the U-shaped heat exchange tube 1, and the middle wing portions 22 are spaced apart between adjacent long wing portions 21; the tips 26 of all the long wing portions 21 gather at the center of the U-shaped heat exchange tube 1, and the tips 26 of the long wing portions 21 are in contact or non-contact with each other, defining a tube core space 24 at the center of the U-shaped heat exchange tube 1; the length of the middle wing portion 22 on the cross section of the U-shaped heat exchange tube 1 is less than the length of the long wing portion 21; the diameter R1 of the tube core space 24 is less than or equal to the spacing H1 between the roots 25 of adjacent fin bodies 20.

[0046] In this embodiment, unlike the straight cylindrical shell in the prior art, which forms a significant temperature difference on both sides of the tube sheet 6, the present application adopts two independent tube sheet header assemblies 19 to separate the cold end and the hot end. This avoids the disadvantage of the ordinary U-tube heat exchanger in which the cold and hot fluids form a significant temperature difference on both sides of the same tube sheet 6, and avoids the problem of the ordinary shell and tube heat exchanger shell and the U-shaped heat exchange tube 1 that is difficult to coordinate the expansion.

[0047] In this embodiment, the two tube sheet header assemblies 19 are respectively connected to the two ends of the U-shaped heat exchange tube 1 in a one-to-one correspondence, which means that the two ends of the U-shaped heat exchange tube 1 are respectively inserted into the two tube sheet header assemblies 19. At the same time, the second medium flowing in the U-shaped heat exchange tube 1 will not penetrate into the first medium flow channel from the tube sheet header assembly 19.

[0048] In this embodiment, the fin body 20 can be straight, porous, serrated, etc.

[0049] In this embodiment, the existence of the tube core space 24 is also to further increase the heat exchange area.

[0050] Unlike existing technologies, this application utilizes the internal space of the U-shaped heat exchange tube by providing a core space 24. The design of the fin body 20 increases the heat exchange area of ​​the tube side beyond the existing primary heat exchange area by further increasing the secondary heat exchange area. The long fins 21 and the middle fins 22 are designed at different heights, resulting in a total heat exchange area that significantly exceeds the inner wall area of ​​a single plain tube by several times, for example, one or twelve times, thereby achieving higher heat exchange efficiency.

[0051] Preferably, on any cross section perpendicular to the axis of the U-shaped heat exchange tube 1, the fin body 20 also includes a plurality of short wing portions 23; the length of the short wing portion 23 on the cross section of the U-shaped heat exchange tube is greater than or equal to half the length of the long wing portion 21; the short wing portion 23 is spaced apart between adjacent long wing portions 21 and middle wing portions 22.

[0052] Preferably, the fin body 20 has multiple sections and is spliced ​​in sequence along the axial direction of the U-shaped heat exchange tube. Each section is made by rolling or stamping from the same plate, and is made into an approximately cylindrical shape through a rolling process and then embedded in the U-shaped heat exchange tube 1. It is also welded and fixed between the root 25 of the fin body 20 and the inner wall of the U-shaped heat exchange tube 1.

[0053] With the aid of the above design, the long wing portion 21, the middle wing portion 22 and the short wing portion 23 can be made to have high strength and low wear, and it is more convenient to subsequently form them into a cylindrical shape.

[0054] The following embodiments are provided for the long wing portion 21, the short wing portion 23 and the middle wing portion 22: First embodiment

[0055] See also Figure 4 , in any cross section perpendicular to the axis of the U-shaped heat exchange tube, the fin body 20 includes a plurality of long wing portions 21 and middle wing portions 22 in the same plane; all the long wing portions 21 are spaced apart along the circumferential inner wall of the U-shaped heat exchange tube, and the root 25 of each long wing portion 21 is connected to the tube wall of the U-shaped heat exchange tube; the root 25 of each fin of the middle wing portion 22 is also connected to the inner wall of the U-shaped heat exchange tube, and the connection point of the root 25 of each middle wing portion 22 is located at the interval between the roots 25 of adjacent long wing portions 21; the length of the middle wing portion 22 is less than the length of the long wing portion 21; the tips 26 of the plurality of long wing portions 21 extend toward the axis of the U-shaped heat exchange tube and are jointly enclosed to form the tube core space 24 near the axis of the U-shaped heat exchange tube; the diameter of the tube core space 24 is less than or equal to the interval between the roots 25 of the adjacent long wing portions 21 and the middle wing portion 22 fins.

[0056] Reference Figure 4As shown, in this case, after the medium enters the U-shaped heat exchange tube, it will contact the surfaces of the long wing portion 21 and the middle wing portion 22, so that the heat of the medium is transferred to the heat exchange medium outside the U-shaped heat exchange tube through the surfaces of the long wing portion 21 and the middle wing portion 22. Second embodiment

[0057] See also Figure 5 , on any cross section perpendicular to the axis of the U-shaped heat exchange tube, the fin body 20 includes a plurality of long wing portions 21 and short wing portions 23 in the same plane; all the long wing portions 21 are spaced apart along the circumferential inner wall of the U-shaped heat exchange tube, and the root 25 of each long wing portion 21 is connected to the tube wall of the U-shaped heat exchange tube; the root 25 of each short wing portion 23 is also connected to the inner wall of the U-shaped heat exchange tube, and the connection point of the root 25 of each short wing portion 23 is located at the interval between the roots 25 of adjacent long wing portions 21; the length of the short wing portion 23 is less than or equal to one-half of the length of the long wing portion 21; the tips 26 of the plurality of long wing portions 21 extend toward the axis of the U-shaped heat exchange tube and are jointly enclosed to form the tube core space 24 near the axis of the U-shaped heat exchange tube; the diameter of the tube core space 24 is less than or equal to the interval between the roots 25 of adjacent long wing portions 21 and short wing portions 23.

[0058] Reference Figure 5 As shown, in this case, after the medium enters the U-shaped heat exchange tube, it will contact the surfaces of the long fins 21 and the short fins 23, so that the heat of the medium is transferred to the heat exchange medium outside the U-shaped heat exchange tube through the surfaces of the long fins 21 and the short fins 23.

[0059] It should be noted that, since the length of the middle wing portion 22 is greater than that of the short wing portion 23 , the heat exchange area is correspondingly larger. Under the same pipe diameter, the heat exchange efficiency of the first embodiment is greater than that of the second embodiment. Third embodiment

[0060] See also Figure 8 , on any cross section perpendicular to the axis of the U-shaped heat exchange tube, the fin body 20 includes a plurality of long fin portions 21, middle fin portions 22, and short fin portions 23 that are in the same plane and have decreasing lengths; all the long fin portions 21 are spaced apart along the circumferential inner wall of the U-shaped heat exchange tube, and the root portion 25 of each long fin portion 21 is connected to the tube wall of the U-shaped heat exchange tube; the root portion 25 of each short fin portion 23 is also connected to the inner wall of the U-shaped heat exchange tube, and the connection point of the root portion 25 of each short fin portion 23 is located at the interval between the roots 25 of adjacent long fin portions 21 (such as Figure 8, two short wings 23 are provided at the interval between the roots 25 of adjacent long wings 21, and a middle wing 22 is provided between the two short wings 23); the root 25 of each middle wing 22 is also connected to the inner wall of the U-shaped heat exchange tube, and the connection point of the root 25 of each middle wing 22 is located at the interval between the roots 25 of the adjacent long wings 21 and the short wings 23; the interval between the roots 25 of the middle wing 22 and the roots 25 of the long wings 21 is equal to the interval between the roots 25 of the long wings 21 and the roots 25 of the short wings 23; the tips 26 of multiple long wings 21 extend toward the axis of the U-shaped heat exchange tube and are jointly enclosed to form the tube core space 24 near the axis of the U-shaped heat exchange tube.

[0061] U-shaped heat exchange tube structure reference Figure 8 As shown, in this case, after the medium enters the U-shaped heat exchange tube, it is distributed to each flow channel, and will contact the surfaces of the long wing portion 21, the middle wing portion 22 and the short wing portion 23, and contact the inner surface of the U-shaped heat exchange tube, so that the heat of the medium is transferred to the heat exchange medium outside the U-shaped heat exchange tube through the surfaces of the long wing portion 21, the middle wing portion 22 and the short wing portion 23 and the U-shaped heat exchange tube.

[0062] It's important to note that, compared to the first and second embodiments, the third embodiment provides more separated flow channels and a larger heat exchange area, making it more suitable for fully utilizing the space within larger U-shaped heat exchange tubes. In practice, the fin heights are not limited to long, medium, or short; they can vary. Depending on the tube diameter, media properties, and operating conditions, this can achieve both high heat exchange efficiency and a simple structure.

[0063] Preferably, a separation space is provided between the two tube sheet header assemblies 19; the U-shaped shell 2 is provided with a medium inlet 3 and a medium outlet 4 connected to the inner cavity of the U-shaped shell 2, and a first medium circulation channel is formed through the medium inlet 3, the space between the inner wall of the U-shaped shell 2 and the outer wall of the U-shaped heat exchange tube 1 to the medium outlet 4; one of the two tube sheet header assemblies 19 is provided with a second medium inlet 16, and the other is provided with a second medium outlet 17, and a second medium circulation channel is formed through the second medium inlet 16, the tube sheet header assembly 19 corresponding to the second medium inlet 16, the inner cavity of the U-shaped heat exchange tube 1, the tube sheet header assembly 19 corresponding to the second medium outlet 17 to the second medium outlet 17.

[0064] In the above solution, the first medium (water or steam) flows through the first medium flow channel, and the second medium (water or steam) flows through the second medium flow channel, and the two media will not mix.

[0065] In the above scheme, the disadvantage of a conventional U-tube heat exchanger in which a significant temperature difference is formed between the hot and cold fluids on both sides of the same tube sheet 6 can be avoided by cooperating with the U-shaped shell 2 and the two tube sheet header assemblies 19. Specifically, the two open ends of the U-shaped shell 2 are directly guided to be sealed and connected to the two tube sheet header assemblies 19 in a one-to-one correspondence. In this way, the first medium will flow in the first medium flow channel, and the second medium will flow in the second medium flow channel. Since there is a gap between the two open ends of the U-shaped shell 2, the heat between the two tube sheet header assemblies 19 can be separated.

[0066] Preferably, the tube sheet and header assembly 19 is composed of a tube sheet 6 and a header 5, and the header 5 includes a flange 7, a head 8 and a connecting pipe 18; one side of the tube sheet 6 is sealed and connected to the open end of the U-shaped shell 2, and the other side is fastened to the flange 7 of the header 5 through a gasket and bolts; the side of the flange 7 away from the tube sheet 6 is sealed and welded to the head 8, and the end face of the tube sheet 6 and the inner wall of the head 8 jointly define a converging chamber 9 for collecting or distributing the second medium; the connecting pipe 18 is connected to the head 8, and the pipe mouth of the connecting pipe 18 serves as the second medium inlet 16 or the second medium outlet 17; the end of the U-shaped heat exchange tube 1 passes through the tube sheet 6 and is sealed and connected to it, and is connected to the converging chamber 9.

[0067] With the above design, the tube sheet header assembly 19 can simultaneously achieve the purpose of sealing the open end of the U-shaped shell 2 and guiding the medium to flow in the second medium flow channel.

[0068] Specifically, one side of the tube sheet 6 structure is sealed and connected to the open end of the U-shaped shell 2, and the other side is sealed and connected to the flange 7 plate (the connection method is bolt connection). Then, the end of the U-shaped heat exchange tube 1 is guided through the tube sheet 6 structure and sealed therewith, and then extended into the converging chamber 9. At this time, the medium inlet and medium outlet 4 on the peripheral surface of the U-shaped shell 2 and the inner cavity of the U-shaped shell 2 sealed by the two tube sheet header assemblies 19 constitute a first medium flow channel. That is, the first medium will flow in the first medium flow channel, and at the same time, the second medium will be guided into one of the converging chambers 9, so that the second medium will flow in the second medium flow channel and then be discharged from the other converging chamber 9.

[0069] Preferably, the tube sheet 6 includes a tube sheet body 10, a thermal insulation gasket 11 and a pressure plate 12, which are arranged in sequence from the outside of the shell to the inside of the shell along the axial direction at the open end of the U-shaped shell 2; the tube sheet body 10 has a relative inner surface and an outer surface; the thermal insulation gasket 11 and the pressure plate 12 are both located inside the U-shaped shell 2, and the thermal insulation gasket 11 is arranged close to the tube sheet body 10; the thermal insulation gasket 11 is used to reduce the heat of the first medium transferred to the tube sheet body 10.

[0070] In the above solution, the U-shaped heat exchange tube 1 passes through the pressing plate 12 and the insulating gasket (sealing can be achieved by expansion, welding or sealing gaskets), and extends into the converging chamber 9.

[0071] With the help of the above design, the tube sheet 6 structure can simultaneously isolate the temperatures of both sides of the tube sheet 6 structure, that is, the front and back surfaces, and at the same time prevent the generation of a large temperature around the open end of the U-shaped shell 2. Specifically, since the insulating gasket is located inside the open end of the U-shaped shell 2 and is arranged in close contact with the front surface of the tube sheet body 10, the temperature of the first medium flowing in the first medium flow channel will not be transferred to the back surface in large quantities. At the same time, since the insulating gasket and the interior of the U-shaped shell 2 are in an excessive or interference fit, the heat transferred from the second medium to the tube sheet body 10 will not be transferred to the side around the open end of the U-shaped shell 2.

[0072] The insulating gasket is made of insulating materials such as polymer-based composite materials. Its thermal insulation effect significantly reduces the temperature difference between the two sides of the tube sheet body 10, that is, reduces the temperature difference thermal stress on the two sides of the tube sheet body 10. At the same time, it also reduces the risk of structural failure of the tube sheet 6 due to stress corrosion and stress cracking, thereby extending the service life of the equipment.

[0073] Preferably, a plurality of U-shaped heat exchange tubes 1 are provided, and the plurality of U-shaped heat exchange tubes 1 are combined to form a tube bundle structure 13 through a baffle 15 provided in the U-shaped shell 2 .

[0074] With the above design, the heat exchange between the first medium and the second medium is more complete.

[0075] Preferably, the thermal insulation gasket 11 is provided with a through hole 14 for guiding the U-shaped heat exchange tube 1 into the converging chamber 9 .

[0076] With the above design, the U-shaped heat exchange tube 1 can extend to the converging chamber 9 through the through hole 14. Furthermore, a sealing member or other structure can be provided at the end of the through hole 14 to achieve sealing.

[0077] It should be noted that the through holes 14 are the corresponding tube holes on the aforementioned tube sheet header assembly 19. The through holes 14 are provided on the entire tube sheet 6.

[0078] Preferably, a plurality of baffles 15 are provided in the U-shaped shell 2 , and all the baffles 15 are arranged in a direction perpendicular to the axis of the U-shaped heat exchange tube 1 and in an inverse order.

[0079] With the help of the above design, when the first medium flows in the space between the inner wall of the U-shaped shell 2 and the outer wall of the U-shaped heat exchange tube 1, it can be blocked and limited by the baffle 15, so that the flow path of the first medium in the space becomes longer, thereby improving the heat exchange efficiency.

[0080] That is, the baffle 15 forces the first medium to flush the U-shaped heat exchange tube laterally to improve the heat exchange efficiency.

[0081] The reverse order means that the baffles 15 are circular in shape with flat notches. When arranged, the notches of adjacent baffles 15 are alternately arranged so that they face the inside (in the positive order) and outside (in the negative order) of the U-shaped heat exchange tube, thereby fully guiding the flow of the first medium.

[0082] Working principle: One side of the tube sheet 6 is sealedly connected to the open end of the U-shaped shell 2, and the other side is sealedly connected to the flange 7. Then, the end of the U-shaped heat exchange tube 1 is guided through the tube sheet 6 and sealed therewith, and then extended into the converging chamber 9. At this time, it passes through the medium inlet 3, the inner wall of the U-shaped shell 2 and the space outside the U-shaped heat exchange tube 1 to the medium outlet 4, forming a first medium flow channel. That is, the first medium will flow in the first medium flow channel, and at the same time, the second medium is guided into one of the converging chambers 9, so that the second medium will flow in the second medium flow channel and then be discharged from the other converging chamber 9. In this process, since the thermal insulation gasket 11 is located inside the open end of the U-shaped shell 2 and is arranged closely to the inner surface of the tube sheet body 10, the temperature of the first medium flowing in the first medium flow channel will not be transferred to the outside in large quantities. At the same time, the thermal insulation gasket 11 and the interior of the U-shaped shell 2 are excessive or interference fit, so the heat transferred from the second medium to the tube sheet body 10 will not be transferred to the surrounding side of the open end of the U-shaped shell 2.

[0083] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A U-tube heat exchanger having a U-shaped shell, characterized in that: The invention comprises a U-shaped heat exchange tube (1), a U-shaped shell (2), and two tube sheet header assemblies (19); the U-shaped heat exchange tube (1) is arranged in the U-shaped shell (2), and the spatial direction of the U-shaped heat exchange tube (1) in the U-shaped shell (2) matches the inner cavity contour of the U-shaped shell (2); the two open ends of the U-shaped shell (2) are welded to the two corresponding tube sheet header assemblies (19), and the two end heads of the U-shaped heat exchange tube (1) are respectively connected to the corresponding tube holes on the tube sheet header assemblies (19); The heat exchanger further comprises a fin structure arranged in the U-shaped heat exchange tube (1), the fin structure being uniformly distributed along the circumferential inner wall of the U-shaped heat exchange tube (1), the fin structure comprising a plurality of fin bodies (20) distributed on the circumferential inner wall of the U-shaped heat exchange tube (1), the fin bodies (20) being arranged at intervals so that the interior of the U-shaped heat exchange tube (1) is divided into a plurality of medium flow channels (27); each fin body (20) has a root portion (25) fixedly connected to the inner wall of the U-shaped heat exchange tube (1) and a tip end (26) extending toward the center of the U-shaped heat exchange tube (1); On any cross section perpendicular to the axis of the U-shaped heat exchange tube (1), the fin body (20) includes a plurality of long wing portions (21) and middle wing portions (22) in the same plane; the long wing portions (21) are spaced apart on the circumferential inner wall of the U-shaped heat exchange tube (1), and the middle wing portions (22) are spaced apart between adjacent long wing portions (21); the tips (26) of all the long wing portions (21) gather at the center of the U-shaped heat exchange tube (1), and the tips (26) of the long wing portions (21) are in contact or non-contact with each other, defining a tube core space (24) at the center of the U-shaped heat exchange tube (1); The length of the middle wing portion (22) in the cross section of the U-shaped heat exchange tube (1) is shorter than the length of the long wing portion (21); and the diameter of the tube core space (24) is shorter than or equal to the spacing between the roots (25) of adjacent fin bodies (20).

2. The U-tube heat exchanger with a U-shaped shell according to claim 1, characterized in that: On any cross section perpendicular to the axis of the U-shaped heat exchange tube (1), the fin body (20) further comprises a plurality of short fin portions (23); the length of the short fin portion (23) on the cross section of the U-shaped heat exchange tube is greater than or equal to half the length of the long fin portion (21); The short wing portion (23) is arranged at intervals between the adjacent long wing portion (21) and middle wing portion (22).

3. The U-tube heat exchanger with a U-shaped shell according to claim 1, characterized in that: The fin body (20) has multiple sections and is spliced ​​in sequence along the axial direction of the U-shaped heat exchange tube. Each section is made by rolling or stamping on the same plate, and is made into a nearly cylindrical shape through a rolling process, and then is embedded in the U-shaped heat exchange tube (1), and is welded and fixed between the root (25) of the fin body (20) and the inner wall of the U-shaped heat exchange tube (1).

4. The U-tube heat exchanger with a U-shaped shell according to claim 1, characterized in that: A separation space is provided between the two tube sheet header assemblies (19); The U-shaped shell (2) is provided with a medium inlet (3) and a medium outlet (4) communicating with the inner cavity of the U-shaped shell (2), and a first medium flow channel is formed through the medium inlet (3), the space between the inner wall of the U-shaped shell (2) and the outer wall of the U-shaped heat exchange tube (1) to the medium outlet (4); One of the two tube sheet header assemblies (19) is provided with a second medium inlet (16), and the other is provided with a second medium outlet (17). A second medium flow channel is formed through the second medium inlet (16), the tube sheet header assembly (19) corresponding to the second medium inlet (16), the inner cavity of the U-shaped heat exchange tube (1), the tube sheet header assembly (19) corresponding to the second medium outlet (17), and the second medium outlet (17).

5. The U-tube heat exchanger with a U-shaped shell according to claim 4, characterized in that: The tube sheet and header assembly (19) is composed of a tube sheet (6) and a header (5), wherein the header (5) includes a flange (7), a head (8) and a connecting pipe (18); One side of the tube sheet (6) is sealed to the open end of the U-shaped shell (2), and the other side is fastened to the flange (7) of the header (5) through a gasket and bolts. The side of the flange (7) away from the tube sheet (6) is sealed and welded to the head (8), and the end surface of the tube sheet (6) and the inner wall of the head (8) jointly define a convergence chamber (9) for collecting or distributing the second medium; The connecting pipe (18) is connected to the sealing head (8), and the pipe opening of the connecting pipe (18) serves as the second medium inlet (16) or the second medium outlet (17); The end of the U-shaped heat exchange tube (1) passes through the tube plate (6) and is sealed therewith, and is communicated with the converging chamber (9).

6. The U-tube heat exchanger with a U-shaped shell according to claim 5, characterized in that: The tube sheet (6) includes a tube sheet body (10), a heat insulating gasket (11), and a pressure plate (12) arranged in sequence along the axial direction from the outside of the shell to the inside of the shell at the open end of the U-shaped shell (2); The tube sheet body (10) has an inner surface and an outer surface opposite to each other; The thermal insulation gasket (11) and the pressure plate (12) are both located inside the U-shaped shell (2), and the thermal insulation gasket (11) is arranged in close contact with the tube sheet body (10); the thermal insulation gasket (11) is used to reduce the transfer of heat from the first medium to the tube sheet body (10).

7. The U-tube heat exchanger with a U-shaped shell according to claim 1, characterized in that: A plurality of U-shaped heat exchange tubes (1) are provided, and the plurality of U-shaped heat exchange tubes (1) are combined to form a tube bundle structure (13) via baffles (15) provided in the U-shaped shell (2).

8. The U-tube heat exchanger with a U-shaped shell according to claim 1, characterized in that: A plurality of baffles (15) are provided in the U-shaped shell (2), and all the baffles (15) are arranged in a direction perpendicular to the axis of the U-shaped heat exchange tube (1) and in an inverse order.

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