A cast housing type EGR cooler

Abstract

The application relates to a cast shell type EGR cooler which comprises an air inlet joint connected with an elastic structure with a bellows and a sleeve, the outer periphery of the elastic structure is fixedly connected with an input end flange cover, the input end flange cover is bolt-connected with one end of a cast pipe shell through an input end sealing gasket, the other end of the pipe shell is bolt-connected with a fixed structure and an output end flange cover with an output pipe joint through an output end sealing ring; the elastic structure is welded with a tube plate at one end of a tube bundle, and the other end of the tube bundle is welded with the fixed structure. One end of the tube bundle is provided with the fixed structure, and the other end is provided with the elastic structure, so that the dislocation between the pipe shell and the tube bundle due to thermal expansion and cold shrinkage is solved; the flexible structure of the double-layer bellows is used for compensating the axial displacement of a heat exchange core, the influence of thermal expansion and cold shrinkage on the heat exchange core is reduced, the double-layer bellows is placed at the air inlet end, the water inlet structure of the shell is combined, the water flow space is increased, and the uniformity of water flow is ensured.

Description

Technical Field

[0001] This invention relates to a cast-shell type EGR cooler, which is an auxiliary device for mechanical equipment and a cooler for the recirculation system of an automobile engine. Background Technology

[0002] With the continuous upgrading of vehicle emission standards, exhaust gas recirculation systems have been widely used in heavy-duty diesel and natural gas engines. Compared with light-duty engines, medium and heavy-duty engines have large exhaust gas flow and high temperature. Considering the thermal resistance and cooling effect caused by high vibration and high thermal shock of heavy-duty engines, as well as the risk of internal boiling, the EGR cooler needs to have high performance and high reliability.

[0003] (1) In the prior art, the coolant of the coolant in most coolers directly exchanges heat with the tube bundle in the high-temperature exhaust gas flow zone. The gas side temperature is as high as 800°C. If there is uneven distribution of coolant in some areas, water dead zone is easily generated, which affects gas-liquid heat exchange. Modal boiling occurs on the liquid side, the surface of the heat exchange tube bundle continues to dry burn, and thermal cracks occur on the tube bundle wall.

[0004] (2) Most of the tube bundle support methods of the existing coolers adopt the inter-tube support method, that is, the water channel fin structure is added between the tube bundles to support the tube bundles. However, for heavy coolers, the tube bundle length is generally more than 600mm. The tube bundles are too long and there is no auxiliary support structure between the tube bundle and the shell. The natural frequency of the internal tube bundles will be relatively low. Due to the long-term vibration of the engine and the thermal expansion and contraction stress caused by thermal shock, reliability problems are likely to occur (especially structural failure at the end), and resonance is likely to occur.

[0005] (3) In order to cope with the axial displacement of the tube bundle and the radial main support of the tube bundle, most of the existing solutions adopt the O-ring + end joint structure. On the one hand, the O-ring is used for sealing, and on the other hand, the end joint is used to support the tube bundle. This method has high requirements for the reliability of the O-ring. The O-ring is prone to failure due to long-term compression and wear. Summary of the Invention

[0006] To overcome the problems of existing technologies, this invention proposes a cast-shell type EGR cooler. To address the misalignment stress between the cast shell and the plate-made tube bundle, the cooler employs a structure where the rigid connection between the connecting pipe and the tube bundle within the shell is designed to generate misalignment along the longitudinal direction. This eliminates the destructive stress caused by misalignment due to uneven thermal expansion and contraction between the shell and the tube bundle, achieving a cast shell without copper, effectively improving the overall rigidity of the heat exchanger. The cooler shell is made of cast material, which, to cope with the impact of thermal shock on the thermal expansion and contraction stress of the tube bundle, and also elastically compensates for radial deformation of the tube bundle, provides auxiliary support in the radial direction, improving the overall reliability of the tube bundle. The telescopic structure design provides primary support in the radial direction of the tube bundle. The corrugated pipe design in the telescopic structure improves coolant flow, increases water flow space, reduces the risk of localized thermal boiling at the high-temperature end, and avoids dry burning of the tube bundle wall due to thermal boiling, thus preventing cracks.

[0007] The objective of this invention is achieved as follows: A cast shell type EGR cooler includes: an inlet connector, which is connected to a double-layer telescopic structure with a bellows and a sleeve; the outer circumference of the telescopic structure is fixedly connected to an input end flange cover; the input end flange cover is bolted to one end of the cast shell via an input end sealing gasket; the other end of the shell is bolted to a fixed structure and an output end flange cover with an output pipe connector via an output end sealing ring; the telescopic structure is welded to a tube sheet at one end of a tube bundle, and the tube sheet at the other end of the tube bundle is welded to a fixed structure.

[0008] Furthermore, the telescopic structure includes: a constricted tube, the large end of which is welded to the air inlet connector, a slip ring fixed on the outer circular surface of the small end of the constricted tube, the outer circular surface of the slip ring being slidably connected to the inner circular surface of the sliding tube, and the sliding tube having a diffuser section with an flared end, the diffuser section being welded to the tube sheet of the tube bundle.

[0009] Furthermore, the slip ring is a ceramic ring.

[0010] Furthermore, a sliding support mechanism is provided on the outer circular surface of the sliding tube and in the middle part of the heat exchange tube bundle.

[0011] Furthermore, the sliding support mechanism is an arc-shaped spring, with both ends of the arc-shaped spring fixedly connected to the outer circular surface of the sliding tube or the middle part of the tube bundle, and the back of the arc-shaped spring pressing against the inner wall of the tube shell.

[0012] Furthermore, the bow-shaped spring is connected to the heat exchange tube bundle via two support plates welded to it.

[0013] Furthermore, the outer edge of the support plate is provided with a plurality of flanges evenly distributed, and the flanges are connected to the locking holes on the bow-shaped spring sheet.

[0014] Furthermore, the fixing structure includes: a flange plate welded to the tube sheet, wherein the flange plate is welded to the connecting plate.

[0015] Furthermore, the shell is provided with reinforcing ribs and vertical combined supports with fixing bolt holes, and the cross-sectional shape of the shell is rectangular or circular.

[0016] Furthermore, the tube bundle is also provided with at least one baffle.

[0017] The advantages and beneficial effects of this invention are as follows: The fixed structure at one end of the tube bundle and the telescopic structure at the other end solve the misalignment caused by thermal expansion and contraction between the tube shell and the tube bundle. The flexible structure of the double-layer corrugated pipe in the telescopic structure compensates for the axial displacement of the heat exchange core, reducing the impact of thermal expansion and contraction on the heat exchange core. The double-layer corrugated pipe is placed at the air inlet end, combined with the water inlet structure of the shell, increasing the water flow space and ensuring uniform water flow, effectively reducing the risk of localized thermal boiling at the high-temperature end. The axial displacement compensation of the telescopic structure (utilizing the flexible compensation capability of the corrugated pipe), the radial main support, and the improvement of the water flow space and uniformity at the water inlet end reduce the risk of boiling. The spring design in the middle acts as an auxiliary support, compensating for deformation in the middle of the long tube bundle, while increasing the overall natural frequency of the tube bundle, reducing the risk of resonance between the cooler and the engine. Another feature of the double-layer structure is that the sleeve protects the corrugated pipe. A corrugated pipe is installed at the water inlet to increase the water flow space, improve the uniformity of water flow, and reduce the risk of local thermal boiling of the pipe wall in the high-temperature zone. The guide pipe and ceramic ring structure that works with the corrugated pipe serve two purposes: firstly, to provide thermal protection for the corrugated pipe and to provide insulation; secondly, the ceramic ring provides radial support for the pipe bundle and reduces frictional resistance in the axial direction. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 These are schematic diagrams of the coolers described in Embodiments 1 and 4 of the present invention;

[0020] Figure 2 This is a schematic diagram of the telescopic structure of the cooler described in Embodiment 2 of the present invention;

[0021] Figure 3 This is a schematic diagram of the internal support structure of the cooler described in Embodiments 5 and 6 of the present invention;

[0022] Figure 4 This is a schematic diagram of the structure of the support plate described in Embodiment Six of the present invention. Figure 3 A-direction view;

[0023] Figure 5 This is a schematic diagram of the fixing structure described in Embodiment 8 of the present invention. Detailed Implementation

[0024] Example 1:

[0025] This embodiment is a cast shell type EGR cooler, such as Figure 1 As shown. This embodiment includes: an air inlet connector 1, which is connected to a double-layer telescopic structure 2 with a bellows and a sleeve; the outer circumference of the telescopic structure is fixedly connected to an input end flange cover 3; the input end flange cover is bolted to one end of a cast tube shell 5 via an input end sealing gasket 4; the other end of the tube shell is bolted to a fixed structure 7 and an output end flange cover 8 with an output pipe connector via an output end sealing ring 6; the telescopic structure is welded to a tube sheet 9.1 at one end of a tube bundle 9; and the tube sheet 9.2 at the other end of the tube bundle is welded to the fixed structure.

[0026] An intake connector is a device that connects to the engine's exhaust pipe or EGR valve to input exhaust gases from the engine. In this embodiment, to address the issue of thermal expansion and contraction differences between the heat exchange tube bundle and the tube shell, one end of the heat exchange tube bundle is fixed with a fixed structure, while the other end is constrained vertically and horizontally (radial constraint) by a telescopic structure. It can expand and contract relatively along its length (axial direction), thus resolving the problem of thermal expansion and contraction differences between the heat exchange tube bundle and the tube shell, while also providing auxiliary support in the radial direction.

[0027] The expansion and contraction structure is key to this embodiment. Since the heat exchange tube bundle carries incandescent engine exhaust gas, with temperatures reaching as high as 800°C, even after heat exchange, the gas temperature remains in the tens of degrees Celsius, resulting in significant thermal expansion. Although thermal expansion is isotropic, it is more pronounced in the longitudinal direction for long tubes. In contrast, the shell, which carries cooling water of the same length as the tube bundle, has a relatively lower temperature and, being a cast component, its thermal expansion is less than that of the tube bundle. Therefore, the shell must constrain the tube bundle circumferentially (up, down, left, and right) to ensure unobstructed airflow, while also providing sufficient expansion and contraction space in the longitudinal direction (axial direction) to compensate for the difference in thermal expansion and contraction between the shell and the tube bundle, ensuring the cooler maintains stable long-term operation.

[0028] There are various options for the telescopic structure, such as using corrugated pipes or telescopic sleeves. This embodiment combines both: an outer corrugated pipe and an inner telescopic sleeve, organically combining the excellent sealing of the corrugated pipe with the constraint structure of the telescopic sleeve to achieve both sealing and telescopic effects. The sleeve consists of a constricted tube, a sliding tube, and a slip ring. One end of the constricted tube is fixedly connected to the pipe shell or flange cover, which can be done by welding or bolting. The other end of the constricted tube is fitted onto one end of the sliding tube, and the constricted tube and the sliding tube are connected by a slip ring. The slip ring allows relative displacement between the constricted tube and the sliding tube, resulting in relative axial movement of the sleeve, but constraining circumferential relative displacement. The other end of the sliding tube is fixedly connected to one side of the tube bundle's tube sheet by welding, forming a circumferential (up, down, left, and right) constraint on the tube bundle by the sleeve, while providing the tube bundle with telescopic space in the longitudinal direction.

[0029] The fixed structure is a structure that fixes the other end of the tube bundle to the tube shell, forming a constraint of the tube bundle on the tube bundle in all directions. The tube bundle can be connected to the tube sheet and the tube shell or flange cover by welding or bolting.

[0030] The casing described in this embodiment is manufactured using a casting process. The casing has an inlet 10 and an outlet 11 at both ends. One end of the inlet has a telescopic structure, which is also the air inlet, to allow hot air to contact the cooler water, improving heat exchange efficiency. The outlet is located at the fixed end. The cast casing can be made of cast aluminum, cast iron, or other casting alloys. Since it is a cast casing, the sealing at both ends cannot be achieved by welding. Therefore, this embodiment uses flanges. Bolt holes evenly distributed on the flanges, along with gaskets or sealing rings, achieve a sealing effect between the flanges and the casing. The external support structure of the casing is designed in conjunction with the engine boundary, allowing for the addition of multiple sets of reinforcing ribs to ensure the overall strength of the casing. The reinforcing ribs can be designed with vertical combined supports that connect with the fixing bolt holes, restricting the cooler's freedom of movement in both the lateral and longitudinal directions, ensuring the cooler is securely fixed. The inner surface of the tube shell should be flat to support the internal heat exchange core, increase the water flow space, ensure the uniformity of water flow, and reduce the risk of thermal boiling of the high-temperature end cooler. The support and inner cavity design of the cooler can be adjusted according to the design requirements of different coolers.

[0031] Flange covers can be cast or pressed from sheet metal. Cast flange covers have poor welding performance, therefore requiring bolted connecting plates and multiple gaskets or sealing rings. Pressed sheet metal flange covers have better welding performance and can be welded directly, thus eliminating the need for connecting plates and allowing direct welding to the tube sheet of the tube bundle.

[0032] To ensure circumferential constraint of the heat exchange tube bundle and expansion structure, a support structure that can move along the inner wall of the tube shell can be installed on the tube bundle and expansion structure. The key point is to constrain the vertical and horizontal displacements while providing a certain amount of expansion space in the longitudinal direction.

[0033] To facilitate water flow within the tube shell, baffles can be installed. These baffles can be fixedly connected to either the tube bundle or the tube shell to prevent slippage stress.

[0034] The sealing components described in this embodiment, such as the input end sealing gasket and the output end sealing ring, can be sealing elements such as encapsulated metal gaskets, composite plate gaskets, and rectangular sealing rings. Encapsulated metal gaskets can be used at high temperatures, utilizing their excellent high-temperature resistance, compressibility, and resilience to ensure both sealing and gasket reliability. Composite plate gaskets and rectangular sealing rings can be used at low temperatures. The composite plate is designed with a fully reinforced structure, i.e., an arc-shaped cross-section is pressed into the composite plate, with a height of 0.4 mm and a width of 4 mm. The coating compression rate can be around 10%, and the resilience rate can reach 50%-90%.

[0035] Rectangular sealing rings are used for water circuit sealing, while composite plate gaskets are used for air circuit sealing. The combination of composite plates and rectangular sealing rings ensures better sealing performance and improves the reliability of the cooler. The encapsulated metal gaskets are made of embedded metal materials (stainless steel, tin-plated iron), encapsulated non-metallic materials (mica, graphite), and their thickness are considered. The coating area and rib design dimensions of the composite plate are also taken into account. The size and material (fluororubber, silicone rubber) of the rectangular sealing rings are selected based on the different working environments and reliability requirements of the cooler.

[0036] Example 2:

[0037] This embodiment is an improvement upon Embodiment 1, detailing the telescopic structure. The telescopic structure in this embodiment includes: a constricted tube 2.1, the large end of which is welded to the air inlet connector; a slip ring 2.2 fixed to the outer surface of the small end of the constricted tube; the outer surface of the slip ring slidably connected to the inner surface of a sliding tube 2.3; the sliding tube having a flared diffuser section 2.31, which is welded to the tube sheet of the tube bundle; and a corrugated tube 2.4 surrounding the constricted tube and the sliding tube. Figure 2 As shown.

[0038] The constricted tube acts as a guide tube, directing the incoming hot air towards the tube bundle. The constricted tube can be equipped with an assembly groove for installing a slip ring, which can be a ceramic ring with a two-semi-ring structure. The slip ring and the constricted tube fit together with a small clearance to form a fixed whole. The constricted tube can be welded to a connecting plate with a flange cover. The connecting plate and the cast flange cover are connected to the tube shell by bolts. Alternatively, without a connecting plate, the constricted tube can be directly welded to a plate-stamped flange cover. A sliding tube is fitted onto the constricted tube, and its inner wall is supported by a slip ring. The sliding tube can move relative to the constricted tube axially. The sliding tube is welded to the tube sheet of the tube bundle, forming a single unit. Thus, when the tube bundle expands or contracts along its length, the sliding tube also moves along its length (axial direction). The constricted tube is fixed and cannot move, but due to the action of the slip ring, relative displacement between the constricted tube and the sliding tube along the length (axial direction) is allowed, but the vertical and horizontal displacement of the sliding tube is constrained. A corrugated pipe is a type of tube that allows for a certain degree of freedom in both axial and radial directions and has good weldability. The corrugated pipe is fitted over the constricted pipe and the sliding pipe and welded to both to seal them, completely isolating the inside of the pipe from the outside. Since the corrugated pipe has a certain degree of freedom in all directions and in the axial direction, the corrugated pipe alone cannot guarantee the constraint of the pipe bundle in all directions. Therefore, this embodiment adopts an internal slip ring mechanism, which constrains the displacement of the pipe bundle in all directions and also plays a good role in axial displacement compensation.

[0039] The bellows structure used for axial displacement compensation also has high requirements for the reliability of the bellows. Single-layer bellows are commonly used, but their high stiffness leads to a higher risk of failure. The auxiliary support structure of the internal heat exchange core often uses water channel fins, which significantly impacts water-side pressure loss and affects the overall performance of the cooler. This embodiment employs a double-layer structure, effectively reducing the failure risk of single-layer bellows and improving the reliability of the cooler.

[0040] Example 3:

[0041] This embodiment is an improvement on the above embodiment, and is a refinement of the slip ring in the above embodiment. The slip ring described in this embodiment is a ceramic ring.

[0042] Ceramics possess excellent impact and heat resistance, making them ideal materials for thermal insulation and sliding surfaces. The ceramic ring described in this embodiment provides radial support to the heat exchange core. Simultaneously, the low surface roughness and low coefficient of sliding friction of the ceramic ring result in minimal axial displacement friction resistance to the heat exchange core, thus not affecting the displacement compensation function of the double-layer bellows and ensuring the overall thermal shock resistance and vibration resistance of the cooler structure.

[0043] The constricted tube has a groove for assembling ceramic rings. Two ceramic rings, each a semi-ring structure, fit with the constricted tube with a small clearance. The outer surface of the ceramic ring fits with the inner wall of the sliding tube with a clearance. While ensuring proper assembly, the ceramic rings provide radial support to the heat exchange core. Furthermore, the low surface roughness and low coefficient of sliding friction of the ceramic rings result in minimal frictional resistance to axial displacement of the heat exchange core, thus not affecting the displacement compensation function of the double-layer bellows. This ensures the overall thermal shock resistance and vibration resistance of the cooler structure. In specific structural designs, depending on the size and reliability requirements of the constricted tube, the ceramic rings can be designed in combinations of two, three, or more to guarantee the reliability of the internal heat exchange core.

[0044] Example 4:

[0045] This embodiment is an improvement upon the above embodiment, refining the internal support within the tube shell. In this embodiment, a sliding support mechanism is provided on the outer surface of the sliding tube and in the middle of the heat exchange tube bundle (see 12-1, 12-2). Figure 1 .

[0046] The sliding support mechanism described in this embodiment restricts the vertical and horizontal (radial) movement of the heat exchange tube bundle, thus constraining it but not restricting its longitudinal (axial) expansion and contraction. The sliding support structure is installed on the sliding tube or in the middle of the heat exchange tube bundle. Since the sliding tube is at the free end of the heat exchange tube bundle, it is crucial to implement measures to restrict its radial displacement. When the heat exchange tube bundle is short, a sliding support mechanism may not be necessary in the middle. However, when the heat exchange tube bundle is long, the pulsating hot air (caused by engine exhaust) can create unpredictable internal impacts on the tube bundle, causing deformation. Therefore, a sliding support mechanism is needed in the middle of the tube bundle to prevent swaying within the tube shell, which could affect heat exchange efficiency and damage the heat exchange tube bundle.

[0047] There are several options for sliding support mechanisms. One option is a simple bent plate, where a support plate is placed at one cross-section of the heat exchanger tube bundle. The support plate has through holes through the tube bundle, and is welded to the heat exchanger tubes. The edge of the support plate is bent. When the tube bundle expands or contracts in the longitudinal direction (axial direction), the bent edge can slide against the inner wall of the tube shell. However, when the tube bundle swings up, down, left, or right (radial displacement), the edge of the support plate is constrained by the tube shell and cannot swing in these directions, thus constraining the tube bundle. The drawback of this method is that a large gap must be left between the edge of the support plate and the inner wall of the tube shell to prevent the support plate from jamming after thermal expansion. However, if the gap is too large, it will not provide good constraint for relatively small tube bundle swings. Therefore, the edge of the support plate is best made elastic to better adapt to different tube bundle swing conditions.

[0048] Example 5:

[0049] This embodiment is an improvement upon the above embodiment, detailing the internal support within the tube shell. The sliding support mechanism in this embodiment is an arc-shaped spring plate 12.1. Both ends of the arc-shaped spring plate are fixedly connected to the outer circular surface of the sliding tube or the middle portion of the tube bundle. The arc-shaped back 12.11 of the arc-shaped spring plate rests against the inner wall of the tube shell. Figure 3 As shown.

[0050] The bow-shaped spring is not fixed to the inner wall of the tube shell. The bow-shaped spring can slide on the inner wall of the tube shell to eliminate the displacement caused by the thermal expansion and contraction of the tube bundle.

[0051] There are several ways to fix the bow-shaped spring to the tube bundle or to the constricted tube, such as by direct welding or by using one or two support plates and locking buckles.

[0052] In this embodiment, the tube bundle is provided with auxiliary support through an arc-shaped spring plate within the shell cavity. Due to the large temperature difference on the gas side, the thermal expansion of the tube bundle is also high. The back of the spring plate is in close contact with the shell cavity, and the elastic deformation capacity of the spring steel is used to compensate for the radial (up, down, left, and right) thermal deformation of the tube bundle, thereby improving its resistance to thermal vibration and thermal shock.

[0053] Example 6:

[0054] This embodiment is an improvement on the above embodiment, and is a refinement of the internal support of the tube shell in the above embodiment. The bow-shaped spring sheet described in this embodiment is connected to the heat exchange tube bundle through two support plates 12.2 that are welded to the heat exchange tube bundle.

[0055] The support plate can be one, two, or more. The support plate can be connected to the tube bundle by direct welding or other methods.

[0056] Example 7:

[0057] This embodiment is an improvement upon the above embodiment, a refinement of the support plate. In this embodiment, the support plate has multiple flanges 12.21 evenly distributed along its outer edge. These flanges connect to the locking holes on the bow-shaped spring piece, as shown below. Figure 4 As shown.

[0058] Figure 4The image shows a support plate installed inside a rectangular tube shell. This support plate has three flanges that connect to four bow-shaped spring clips, maintaining constraint on the tube bundle in all four directions. A through-hole is located in the center of the support plate, through which the tube bundle passes and is welded and fixedly connected. Four or six flanges are arranged around the perimeter of the support plate, and these flanges are press-fitted to the bow-shaped spring clips. The flange structure ensures that the support plate does not fall off while allowing for axial movement without affecting its elastic deformation capacity. The support plate and the inner surface of the shell provide mutual support, acting as auxiliary support for the central part of the heat exchange core. The spacing and dimensions of the two support plates can be determined according to the specific design scheme.

[0059] The outer surface of the sliding tube also has a flange structure, see Figure 1 The support plate and the flange structure on the sliding tube are press-fitted together. The flange structure can ensure that the bow-shaped spring does not fall off, and at the same time ensure that the bow-shaped spring has room for movement in the axial direction. It should not affect the elastic deformation ability of the support plate. The bow-shaped spring and the inner surface of the shell should support each other, and play a role in providing auxiliary support for the end of the heat exchange core.

[0060] Example 8:

[0061] This embodiment is an improvement upon the above embodiment, detailing the fixing structure. The fixing structure in this embodiment includes: a flanged plate 7.1 welded to the tube sheet; the flanged plate is welded to a connecting plate 7.2; and the connecting plate is bolted to the tube shell and the output end flange cover. Figure 5 As shown.

[0062] The ends of the tube bundle are tube sheets, which are welded together with flange plates. The flange plates and tube sheets are then welded together. The output flange cover can be made into a collector shape and bolted together with the tube shell and connecting plate to fix the tube bundle.

[0063] Example 9:

[0064] This embodiment is an improvement upon the above embodiment, a refinement of the shell. The shell in this embodiment is provided with reinforcing ribs 5.2 and a vertical combined support with fixing bolt holes 5.1. The cross-sectional shape of the shell is rectangular or circular, such as... Figure 1 As shown.

[0065] The cast shell integrates the shell with the external support structure at the engine boundary. It can employ a vertical combined support design with fixing bolt holes and stiffeners to ensure shell rigidity and secure fixation of the entire cooler. While ensuring manufacturability and reliability, the shell structure supports the internal heat exchange core and increases the water inlet space.

[0066] Example 10:

[0067] This embodiment is an improvement upon the above embodiment, a refinement of the tube bundle described above. The tube bundle in this embodiment is further provided with at least one baffle plate 13, see [link to embodiment]. Figure 1 .

[0068] Baffles are evenly arranged on the heat exchange core. Some of the baffles have a flanged structure. A small gap is left between the baffles and the inner surface of the shell. While not affecting the overall assembly of the heat exchange core, they can play an auxiliary support role and reduce the reliability risk caused by thermal deformation of the heat exchange tube. Arranging multiple baffles can also have a turbulence effect. The number and spacing of the baffles can be determined according to the specific design scheme.

[0069] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred arrangements, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of the present invention (such as the form of the heat exchange tube, the form of the cooler, the environment in which the cooler is applied, etc.) without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A cast-housing EGR cooler comprising: The air inlet joint is characterized in that the air inlet joint is connected with a double-layer telescopic structure with a bellows and a sleeve, the double-layer telescopic structure can be axially dislocated in a shell, an outer circumference of the double-layer telescopic structure is fixedly connected with an input end flange cover, the input end flange cover is bolted to one end of the cast shell through an input end sealing gasket, the other end of the shell is bolted to a fixed structure and an output end flange cover with an output pipe joint through an output end sealing ring; the double-layer telescopic structure is welded to a tube plate at one end of a heat exchange tube bundle, the other end tube plate of the heat exchange tube bundle is welded to the fixed structure; the double-layer telescopic structure comprises a necked pipe, the large end of the necked pipe is welded to the air inlet joint, the outer circumferential surface of the small end of the necked pipe is fixed with a sliding ring, the outer circumferential surface of the sliding ring is slidably connected with the inner circumferential surface of a sliding pipe, the sliding pipe is provided with a diffusion section with an expanded end, the diffusion section is welded to the tube plate of the heat exchange tube bundle; the sliding ring is a ceramic ring; the outer circumferential surface of the sliding pipe and the middle part of the heat exchange tube bundle are provided with a sliding support mechanism; the fixed structure comprises a flange plate welded to the tube plate, and the flange plate is welded to a connecting plate.

2. The cooler of claim 1, wherein, The sliding support mechanism is an arc-shaped elastic sheet, two ends of the arc-shaped elastic sheet are fixedly connected with the outer circumferential surface of the sliding pipe or the middle part of the heat exchange tube bundle, and the back of the arc-shaped elastic sheet is supported on the inner wall of the shell.

3. The cooler of claim 2, wherein, The arc-shaped elastic sheet is connected with the heat exchange tube bundle through two support plates welded to the heat exchange tube bundle.

4. The cooler of claim 3, wherein, The outer edge of each support plate is uniformly provided with a plurality of flanges, and the flanges are connected with locking holes on the arc-shaped elastic sheet.

5. Cooler according to one of claims 1-4, characterized in that The shell is provided with a reinforcing rib and a vertical combined support with a fixed bolt hole, and the cross-sectional shape of the shell is rectangular or circular.

6. The cooler of claim 5, wherein, The heat exchange tube bundle is further provided with at least one baffle.

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