Tube bundle freeze-proof heat exchanger

Abstract

The utility model discloses a kind of tube bundle anti-freezing crack heat exchangers, including tube shell, tube sheet, tube box, several U-shaped heat exchange tube bundles, glue injection port and conical screw plug.Tube shell first end is closed, second end is fixedly connected tube sheet, lateral wall is equipped with water inlet pipe and water outlet pipe;Tube sheet through-hole contains reaming section and straight section, and straight section is equipped with tube expanding groove.U-shaped tube bundle straight pipe end is inserted into through-hole, and after tube expansion, it is formed gap with reaming section away from tube box with interference fit.The cavity is formed by that tube box is sealed and connected tube sheet outside, refrigerant is into tube bundle through inlet, first cavity, is discharged from second cavity, outlet after heat exchange.Glue injection port is located at tube shell near tube sheet and is communicated gap, for injection sealant, conical screw plug is blocked.Tube shell is equipped with baffle support tube bundle and form circuitous flow channel, first end has temperature measuring joint to measure water temperature, and water drainage pipe is arranged on the side wall away from tube sheet, can efficiently heat exchange and guarantee anti-freezing crack.

Description

Technical Field

[0001] This utility model relates to the field of heat exchanger technology, specifically to a tube bundle anti-freezing and cracking heat exchanger. Background Technology

[0002] Shell-and-tube heat exchangers are widely used heat exchange devices whose core function is to achieve efficient heat transfer between two fluid media. The heat exchange tubes and tubesheets are typically connected by expansion joints. In traditional designs, the through-holes on the tubesheet are often of uniform diameter. This structure is prone to permanent rigid deformation at the connection between the heat exchange tubes (especially thin-walled tubes) and the tubesheet during the expansion process. These deformed areas are highly susceptible to cracking due to stress concentration during subsequent operation, leading to refrigerant leakage.

[0003] To alleviate the aforementioned rigid deformation problem, subsequent improvements included enlarged sections at both ends of the through-hole, which released stress to some extent. However, this structure also introduced an annular gap at the connection. Because low-temperature refrigerant flows inside the heat exchange tube, moisture on the shell side is prone to freezing at this gap, and the stress generated by the expansion of the ice may still cause the heat exchange tube to crack.

[0004] Therefore, the above problems urgently need to be solved. Utility Model Content

[0005] Purpose of the utility model: To overcome the above shortcomings, the purpose of this utility model is to provide a tube bundle anti-freezing and cracking heat exchanger. By designing a tube sheet through-hole structure with an expanded section and tube expansion groove, the straight tube ends of the U-shaped heat exchanger tube bundle, after expansion, can form an interference fit with the straight section of the through hole to ensure a tight connection, while the expanded section reduces rigid deformation during expansion to alleviate stress concentration. At the same time, a glue injection port is provided on the side wall of the tube shell near the tube sheet, which communicates with the annular gap formed by the expanded section and the straight tube ends. Sealant can be injected into the annular gap to fill the gap, and the glue injection port is sealed with a conical screw plug to prevent moisture on the tube shell side from freezing and expanding at the gap due to the low temperature of the refrigerant inside the tube, thereby preventing cracking of the heat exchanger tube bundle and refrigerant leakage, and improving the operational stability and service life of the heat exchanger.

[0006] Technical Solution: This utility model provides a tube bundle anti-freeze crack heat exchanger including a tube shell, the tube shell having a first end and a second end along the axial direction, the first end being closed, and the second end being fixedly connected to a tube sheet; the tube shell sidewall is provided with an inlet pipe and an outlet pipe; the tube sheet has a plurality of through holes along its axial direction, each through hole including an enlarged section located on both sides of the tube sheet along the axial direction and an inner straight section, the straight section having an annular expansion groove on the hole wall; a tube box, the tube box being sealed and fixed to the outside of the tube sheet away from the tube shell, forming a cavity with the tube sheet; and a plurality of U-shaped heat exchange tube bundles, each U-shaped heat exchange tube bundle having... Two straight pipe ends are inserted into the through holes one to one, with the openings of the straight pipe ends facing the cavity and communicating with it. After expansion, the outer wall of the straight pipe end forms an interference fit with the inner wall of the straight section, and an annular gap is formed between the straight pipe end and the expanded section away from the pipe box. A sealant injection port is located on the side wall of the pipe shell adjacent to the pipe plate and is in fluid communication with the gap. When the pipe shell is upright, it is used to inject sealant into the annular gap. A conical plug is threaded to the sealant injection port to seal it. The tube shell forms a chamber to accommodate water, and fluid flow is achieved through inlet and outlet pipes. The first end is closed and the second end is fixed to the tube sheet, forming a closed tube shell side space, providing a basic environment for heat exchange. The straight section of the through hole matches the tube expansion groove, so that the straight tube end of the U-shaped heat exchange tube bundle forms an interference fit after tube expansion, ensuring a tight connection between the tube bundle and the tube sheet. The expanded sections at both ends reduce the rigid deformation of the tube bundle during expansion, providing space for stress release. The straight tube end is inserted into the through hole and expanded and fixed, with the opening communicating with the tube box cavity to realize the flow and heat exchange of refrigerant in the tube bundle. When the tube shell is vertical, the injection port injects sealant into the annular gap to fill the gap. The tapered screw plug is threaded to the injection port to achieve sealing.

[0007] Furthermore, in this application, a tube bundle anti-freeze-crack heat exchanger includes a cavity comprising several first cavities and several second cavities. The tube bundle, on the side furthest from the tube sheet, has several inlets and outlets. The inlets are used to inject refrigerant, which passes through the first cavity and enters the straight tube end of the U-shaped heat exchange tube bundle. After heat exchange, the refrigerant exits from the straight tube end to the second cavity and then exits through the outlet. The first cavity serves as a refrigerant distribution cavity, receiving the refrigerant injected from the inlet and evenly distributing it to the corresponding straight tube end (inlet side) of the U-shaped heat exchange tube bundle, ensuring the refrigerant enters each tube bundle in an orderly manner. The second cavity serves as a collection cavity, collecting the refrigerant exiting from the other straight tube end of the tube bundle after heat exchange, and finally exiting through the outlet, forming a complete refrigerant flow path. The first and second cavities are independent of each other, achieving physical isolation between "unexchanged refrigerant" and "exchanged refrigerant," avoiding mixing and interference between the two within the cavity, and ensuring that the refrigerant flows through the tube bundle in a preset direction for heat exchange.

[0008] Furthermore, in a tube bundle anti-freeze-crack heat exchanger of this application, multiple sets of baffles are provided inside the tube shell between the inlet and outlet pipes. The baffles support the U-shaped heat exchange tube bundle and form a meandering flow channel. The baffles form a non-linear meandering flow channel between the inlet and outlet pipes, forcing the water to change its flow direction and increasing the length of the fluid's flow path within the tube shell.

[0009] Furthermore, in a tube bundle antifreeze heat exchanger of this application, the first end is provided with a temperature measuring connector, which is used to measure the water temperature in the tube shell.

[0010] Furthermore, in a tube bundle antifreeze heat exchanger of this application, a drain pipe is provided on the side wall of the tube shell away from the tube sheet.

[0011] As can be seen from the above technical solution, this utility model has the following beneficial effects: 1. The tube bundle anti-freezing and cracking heat exchanger of this utility model, by setting an enlarged section and a straight section with expansion grooves in the tube sheet through holes, allows the straight tube ends of the U-shaped heat exchanger tube bundle to form an interference fit with the straight section after expansion, ensuring connection strength, and the expansion section can effectively release the expansion stress, avoiding heat exchanger tube cracking caused by stress concentration; at the same time, by injecting sealant into the glue injection port connected to the annular gap and sealing it with a conical screw plug, the space for moisture to freeze and expand in the gap is completely eliminated, fundamentally solving the problem of heat exchanger tube cracking and refrigerant leakage caused by freezing expansion. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a tube bundle antifreeze heat exchanger according to the present invention; Figure 2 This is an exploded view of the structure of a tube bundle antifreeze heat exchanger according to the present invention; Figure 3 for Figure 2 Enlarged view of region A in the middle; Figure 4 This is a schematic diagram of the explosion after removing the tube shell of the tube bundle anti-freezing and cracking heat exchanger structure of this utility model; Figure 5 This is a cross-sectional view of a tube bundle anti-freezing and cracking heat exchanger structure of this utility model after removing the tube shell; Figure 6 for Figure 5 Enlarged view of region B in the middle; Figure 7 This is a partially enlarged schematic diagram of the tube sheet.

[0013] Explanation of reference numerals on the accompanying drawings: 1-Pipe shell, 11-Gap, 12-Baffle plate, 13-Temperature measuring connector, 14-Drain pipe, 1a-First end, 1b-Second end; 2-Inlet pipe; 3-Water outlet pipe; 4-Tube sheet, 41-Through hole, 411-Expanded section, 412-Straight section, 413-Expanded groove; 5-Pipe box, 51-Inlet, 52-Outlet; 6-Cavity, 61-First cavity, 62-Second cavity; 7-U-shaped heat exchanger tube bundle, 71a-straight tube end, 71b-straight tube end, 71-opening; 8-Injection port; 9-Conical plug. Detailed Implementation

[0014] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0015] Example 1 This embodiment provides a tube bundle anti-freeze crack heat exchanger, whose structure is compatible with the attached... Figure 1-7 To achieve efficient heat exchange and freeze-cracking prevention, the specific structural assembly and working process are as follows: I. Structural Assembly Pipe shell and foundation component installation First, the tube shell 1 is pre-treated. The tube shell 1 has a first end 1a and a second end 1b along the axial direction. The first end 1a is sealed by welding. A temperature measuring connector 13 is welded and fixed at a preset position on the first end 1a to ensure that the temperature measuring connector 13 can directly contact the internal space of the tube shell 1 for subsequent real-time monitoring of the water temperature inside the tube. A drain pipe 14 is welded on the side wall of the tube shell 1 away from the tube sheet 4 (the side closer to the first end 1a). The drain pipe 14 is equipped with a valve to facilitate subsequent maintenance and drainage of water accumulated in the pipe. Next, an inlet pipe 2 and an outlet pipe 3 are welded to the corresponding positions on the side wall of the tube shell 1. Then, multiple sets of baffles 12 are fixed inside the tube shell 1 and in the preset mounting holes between the inlet pipe 2 and the outlet pipe 3. The baffles 12 are connected to the bracket on the inner wall of the tube shell 1 by bolts. Adjacent baffles 12 are arranged in an alternating pattern, which can not only support the U-shaped heat exchange tube bundle 7 to be installed later, but also form a meandering flow channel inside the tube shell 1 to extend the fluid flow path.

[0016] Tube sheet connection with U-shaped heat exchanger tube bundle Take a tube sheet 4. The tube sheet 4 has several through holes 41 machined along its axial direction. Each through hole 41 has an enlarged section 411 located on both sides of the tube sheet 4 along its axial direction and a straight section 412 located in the middle. An annular expansion groove 413 is machined on the hole wall of the straight section 412. One side of the tube sheet 4 is fixed to the second end 1b of the tube shell 1 with bolts to ensure that there is no gap leakage between the tube sheet 4 and the tube shell 1. Then, take several U-shaped heat exchange tube bundles 7. Insert the two straight tube ends 71a and 71b of each U-shaped heat exchange tube bundle 7 into the through holes 41 of the tube sheet 4 one by one, so that the opening 71 of the U-shaped heat exchange tube bundle 7 faces the side of the tube sheet 4 away from the tube shell 1. The straight pipe ends 71a and 71b are expanded using a tube expansion device. After expansion, the outer walls of the straight pipe ends 71a and 71b are tightly fitted with the inner wall of the straight section 412 of the through hole 41, forming an interference fit. At the same time, since the diameter of the expanded section 411 is larger than the outer diameter of the straight pipe ends 71a and 71b, an annular gap 11 is naturally formed between the straight pipe ends 71a and 71b and the expanded section 411 on the side away from the pipe box 5.

[0017] Pipe box and sealing structure installation The tube box 5 is bolted and sealed to the outside of the tube sheet 4 away from the tube shell 1, forming a cavity 6 between the tube box 5 and the tube sheet 4. The cavity 6 is divided into several first cavities 61 and several second cavities 62 by internal partitions, and the first cavities 61 and second cavities 62 are independent of each other. Several inlets 51 are opened on the side of the tube box 5 away from the tube sheet 4, corresponding to the positions of the first cavities 61, and several outlets 52 are opened corresponding to the positions of the second cavities 62, ensuring that the openings 71 of the U-shaped heat exchange tube bundle 7 are directly opposite the cavity 6, and that the openings of the straight tube ends 71a are connected to the first cavities 61, and the openings of the straight tube ends 71b are connected to the second cavities 62. Finally, a glue injection port 8 is machined on the side wall of the tube shell 1 adjacent to the tube sheet 4. One end of the glue injection port 8 is connected to the inside of the tube shell 1, and the other end extends to the outside of the tube shell 1. The internal channel of the glue injection port 8 is in fluid communication with the gap 11 formed by the straight tube ends 71a and 71b and the enlarged section 411. The pipe housing 1 is erected vertically, and high-temperature and low-temperature resistant sealant is injected into the annular gap 11 through the injection port 8. After the sealant fills the gap 11 and cures, the conical plug 9 is connected to the injection port 8 by thread to seal the injection port 8 and prevent the fluid in the pipe from leaking from the injection port 8.

[0018] II. Work Process Fluid flow and heat transfer Water to be heated enters the tube housing 1 through inlet pipe 2. Due to the meandering flow path formed by baffle plate 12, the water flows along a meandering path within the tube housing 1, making full contact with the outer wall of the U-shaped heat exchange tube bundle 7 during the process. Simultaneously, refrigerant is injected from inlet 51 of tube box 5, enters the first cavity 61, and then enters the interior of the U-shaped heat exchange tube bundle 7 through the straight tube end 71a. As the refrigerant flows within the U-shaped heat exchange tube bundle 7, it exchanges heat with the water outside the tubes. Under refrigeration conditions, the refrigerant absorbs heat from the water, causing the water temperature to decrease. The refrigerant after heat exchange is discharged from the straight tube end 71b of the U-shaped heat exchange tube bundle 7, enters the second cavity 62, and finally exits the heat exchanger through outlet 52 of tube box 5.

[0019] Monitoring and maintenance During the operation of the heat exchanger, the temperature measuring connector 13 measures the temperature of the water inside the tube shell 1 in real time. The operator can read the water temperature data through the instrument connected to the temperature measuring connector 13 to determine whether the heat exchange effect meets the standard. When the heat exchanger needs to be shut down for maintenance or is not used for a long time in winter, the valve of the drain pipe 14 is opened to completely drain the water in the tube shell 1 through the drain pipe 14 to prevent the water from freezing inside the tube and damaging the components. After the sealant injected into the glue injection port 8 fills the gap 11, it can prevent water from the tube shell side from entering the gap 11, and prevent the water in the gap 11 from freezing and expanding due to the low temperature of the refrigerant in the U-shaped heat exchange tube bundle 7. This prevents the U-shaped heat exchange tube bundle 7 from cracking and the refrigerant from leaking, and ensures the long-term stable operation of the heat exchanger.

[0020] The above embodiments are exemplary and are intended to illustrate the technical concept and features of this utility model, so that those skilled in the art can understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the scope of protection of this utility model.

Claims

1. A tube bundle freeze protection heat exchanger, characterized by: include: The pipe housing (1) has a first end (1a) and a second end (1b) along the axial direction. The first end (1a) is closed, and the second end (1b) is fixedly connected to the pipe plate (4). The side wall of the pipe housing (1) is provided with an inlet pipe (2) and an outlet pipe (3). Tube sheet (4), the tube sheet (4) is provided with a plurality of through holes (41) along its axial direction, each through hole (41) includes an enlarged hole section (411) located on both sides of the tube sheet (4) axial direction and a straight section (412) inside, the hole wall of the straight section (412) is provided with an annular tube expansion groove (413). The tube box (5) is sealed and fixed on the outside of the tube plate (4) away from the tube shell (1), and forms a cavity (6) between the tube box (4) and the tube plate (4). Several U-shaped heat exchange tube bundles (7), with the two straight tube ends (71a, 71b) of each U-shaped heat exchange tube bundle (7) inserted into the through hole (41) respectively, and the opening (71) of the straight tube end (71a, 71b) facing the cavity (6) and communicating with the cavity (6). After the straight pipe ends (71a, 71b) are expanded, their outer walls form an interference fit with the inner wall of the straight section (412), and at the same time, an annular gap (11) is formed between the straight pipe ends (71a, 71b) and the expanded section (411) away from the pipe box (5). The injection port (8) is located on the side wall of the tube shell (1) adjacent to the tube plate (4) and is in fluid communication with the gap (11). When the tube shell (1) is upright, it is used to inject sealant into the annular gap (11). A conical screw plug (9) is threadedly connected to the glue injection port (8) for sealing and plugging the glue injection port (8).

2. The tube bundle anti-freeze crack heat exchanger according to claim 1, characterized in that, The cavity (6) includes several first cavities (61) and several second cavities (62). The corresponding tube box (5) is provided with several inlets (51) and outlets (52) on the side away from the tube sheet (4). The inlet (51) is used to inject refrigerant into the straight tube end (71a) of the U-shaped heat exchange tube bundle (7) after passing through the first cavity (61). After heat exchange, it is discharged from the straight tube end (71b) to the second cavity (62) and then discharged through the outlet (52).

3. The tube bundle anti-freeze crack heat exchanger according to claim 1, characterized in that, The tube shell (1) has multiple sets of baffles (12) between the inlet pipe (2) and the outlet pipe (3). The baffles (12) are used to support the U-shaped heat exchange tube bundle (7) and form a meandering flow channel.

4. The tube bundle anti-freeze crack heat exchanger according to claim 1, characterized in that, The first end (1a) is provided with a temperature measuring connector (13), which is used to measure the water temperature in the pipe shell (1).

5. A tube bundle anti-freeze crack heat exchanger according to claim 1, characterized in that, The pipe shell (1) is provided with a drain pipe (14) on the side wall away from the tube sheet (4).

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