Flat Heat Exchange Tube, Heat Exchanger, And Construction Machine

Abstract

The present invention relates to a flat heat exchange tube. The flat heat exchange tube comprises: planar wall portions extending in length and width directions of the heat exchange tube and spaced apart from each other in a thickness direction of the heat exchange tube, and side wall portions extending in length and thickness directions of the heat exchange tube across side edges of the planar wall portions, wherein at least one planar wall portion of the flat heat exchange tube is provided, in an area adjacent to its mounting position, with a stress relieving portion for relieving stress of a tube wall, the stress relieving portion comprising one or more elongated corrugated sections formed by local arching or recessing of the planar wall portion, and a longitudinal direction of the corrugated section being substantially identical with the width direction of the heat exchange tube. The present invention also relates to a heat exchanger comprising said flat heat exchange tube and a construction machine comprising said heat exchanger.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of and claims priority to prior application Ser. No. 19 / 278,999, filed Jul. 24, 2025 which claims priority to Chinese Patent Application Number 202411048905.6, filed Jul. 31, 2024, which are hereby incorporated by reference in their entirety.TECHNICAL FIELD

[0002] The present invention relates to the technical field of heat dissipation, in particular to a flat heat exchange tube, a heat exchanger for a construction machine and a construction machine comprising the heat exchanger.BACKGROUND ART

[0003] In construction machinery, in order to improve engine power and reduce fuel consumption, a charge air cooler is usually provided to cool, by a coolant, the charge air intended for the engine. Specific applications include engine charge air coolers and compressor charge air coolers. As a charge air cooler, the heat exchanger is usually designed in a tube-fin form, including heat exchange tubes and heat exchange fins. The heat exchange fins and heat exchange tubes are usually connected by an expansion joint process, so are the heat exchange tubes and end tube sheets. The heat exchange tubes and heat exchange fins are usually made of copper. For example, since the charge air cooler for a gas engine uses corrosive medium, the heat exchanger is usually made of stainless steel. This tube-fin design has the following defects: 1) the effective heat exchange area has a low utilization rate, and there is a contact gap between heat exchange elements, which leads to a high thermal resistance and thus a low heat exchange performance; 2) it entails high material costs, a complicated manufacturing process and high labor costs; 3) the stainless steel tube has difficulty in expansion joint, leading to high costs; 4) it has a low production efficiency, not suitable for mass production; 5) hundreds of heat exchange tubes need to be expanded, and it is difficult to control the quality of expansion; 6) mechanical stress and thermal stress are concentrated in the area of expansion joint between the heat exchange tube and the end tube sheet, which makes the tube or tube sheet fracture easily, leading to leakage.

[0004] Accordingly, the present invention aims to overcome one or more of the above problems.SUMMARY OF THE INVENTION

[0005] With respect to the above problems, the present invention proposes an improved flat heat exchange tube and a heat exchanger comprising said flat heat exchange tube, which greatly improves the manufacturing and assembly efficiency, enhances the heat exchange efficiency, ensures the stability of product quality and the reliability of product operation, reduces the manufacturing cost and material cost, and decreases the product in both weight and size.

[0006] According to an aspect of the present invention, there is provided a flat heat exchange tube. The flat heat exchange tube comprises: planar wall portions extending in length and width directions of the heat exchange tube and spaced apart from each other in a thickness direction of the heat exchange tube, and side wall portions extending in length and thickness directions of the heat exchange tube across side edges of the planar wall portions, wherein at least one planar wall portion of the flat heat exchange tube is provided, in an area adjacent to its mounting position, with a stress relieving portion for relieving stress of tube wall, the stress relieving portion comprising one or more elongated corrugated sections formed by local arching or recessing of the planar wall portion, and a longitudinal direction of the corrugated section being substantially identical with the width direction of the heat exchange tube.

[0007] The corrugated feature of the flat heat exchange tube according to the present invention can be directly formed by a stamping process when the tube is manufactured, leading to a high manufacturing efficiency and low costs. This corrugated feature plays an important role in stress mitigation in the subsequent assembly process and operation process, especially in some areas close to the mounting position of the heat exchange tube (the areas where high-temperature and high-pressure pressurized air enters the heat exchange tube but does not exchange heat with the coolant therein), so as to alleviate stress concentration and ensure the stability of product quality and the reliability of heat exchanger operation. There is a large joint area between the flat heat exchange tube and the fin, which is beneficial to reducing the thermal resistance between the heat exchange tube and the fin and improving the heat exchange efficiency. Under the same heat exchange requirements, the heat exchanger can be designed smaller in size and therefore weight.

[0008] In an advantageous embodiment, a first corrugated section is formed on a first planar wall portion of the flat heat exchange tube, and a second corrugated section is formed on a second planar wall portion of the flat heat exchange tube opposite to the first planar wall portion. This can advantageously cope with the situation where the upper and lower planar wall portions of the flat heat exchange tube are subjected to different stresses. The flat heat exchange tube according to the present invention has better stress adaptability and therefore expanded application scenarios.

[0009] In an advantageous embodiment, the first corrugated section bulges in a first direction relative to a plane where the first planar wall portion is located, and the second corrugated section bulges in a second direction relative to a plane where the second planar wall portion is located, wherein the first direction is opposite to the second direction.

[0010] In an advantageous embodiment, the first and second corrugated sections are positioned opposite to each other in the thickness direction of the flat heat exchange tube. This is beneficial to the assembly and positioning of the heat exchange tube to the tube sheet.

[0011] In an advantageous embodiment, the first and second corrugated sections are convex strips arched toward outside of the heat exchange tube. In this configuration, the cross-section of the fluid in the tube is enlarged, and the high-temperature and high-pressure air is branched under the action of the convex strips, which is beneficial to reducing the mechanical stress acting on the tube and the tube sheet. In addition, due to the inherent deformable potential, the convex strip can absorb some inherent mechanical stress on the tube or tube sheet, which can advantageously ensure the quality of the tube and tube sheet and of the connection therebetween, as well as the sealing integrity.

[0012] In an advantageous embodiment, the flat heat exchange tube is made of stainless steel. Thereby the heat exchange tube and the heat exchanger with the heat exchange tube can be applied to more scenarios. Stainless steel is more conducive to the implementation of brazing, thus making the assembly efficiency greatly improved.

[0013] According to another aspect of the present invention, there is provided a heat exchanger for construction machinery. The heat exchanger comprises: a heat exchange core, the heat exchange core comprising: a plurality of flat heat exchange tubes and fins arranged therebetween; a first header box connected to one end of each of the flat heat exchange tubes; and a second header box connected to the other end of each of the flat heat exchange tubes, wherein the flat heat exchange tube is the aforementioned flat heat exchange tube, each of the flat heat exchange tubes is installed to a corresponding header box in such a way that its open end passes through a hole formed on a fixed tube sheet fixedly connected to the corresponding header box and communicates with an interior of the corresponding header box, and the stress relieving portion arranged adjacent to the mounting position is located at a side of the fixed tube sheet away from the corresponding header box.

[0014] In an advantageous embodiment, each of the flat heat exchange tubes is fixedly connected to the fixed tube sheet in a sealed manner by brazing. Compared with the existing expansion joint process, the brazing process has high efficiency and guarantees quality and reliability.

[0015] In an advantageous embodiment, the heat exchanger comprises a tube sheet frame integrally or detachably connected to the header box, and a peripheral side of the fixed tube sheet is fixedly connected with an inner peripheral wall of the tube sheet frame in a sealed manner.

[0016] In an advantageous embodiment, the heat exchanger comprises a floating tube sheet arranged at a distance from the fixed tube sheet and on the side of the fixed tube sheet away from the header box, and a peripheral side of the floating tube sheet faces the inner peripheral wall of the tube sheet frame and maintains a predetermined gap with it, and the flat heat exchange tubes extend through holes of the floating tube sheet and are fixedly connected with it. The arrangement of the floating tube sheet is conducive to guiding the deformation of the planar wall portion of the flat heat exchange tube or endowing it with certain constraint variables, and absorbing some loads or stresses acting on the heat exchange tube and the tube sheet.

[0017] In an advantageous embodiment, at least one stress relieving portion is arranged between paired floating tube sheet and fixed tube sheet in an area of the flat heat exchange tube adjacent to its mounting position. In this way, the floating tube sheet provides protection for the stress relieving portion. When the dynamic load or thermal load is too large, the floating tube sheet can reduce the impact on the stress relieving portion through part of its own deformation, and the stress relieving portion can absorb the remaining load through deformation, thus ensuring that the load on the connection area between the tube and the tube sheet is within a controllable range. Therefore, the structure providing layer-by-layer protection is conducive to improving the operational stability and reliability of the heat exchanger.

[0018] In an advantageous embodiment, flexible material is filled between the paired floating tube sheet and fixed tube sheet and between adjacent flat heat exchange tubes to absorb loads acting on the floating or fixed tube sheet or the flat heat exchange tubes. Advantageously, the flexible material comprises rubber or asphalt. The arrangement of the flexible filler is conducive to ensuring that most of the loads acting on or transmitted from the heat exchange tubes or tube sheets are absorbed to provide a buffering effect for the rigid tubes and tube sheets, and ensuring that the deformation of the tubes and tube sheets is kept as small as possible or almost at a zero level.

[0019] In an advantageous embodiment, the stress relieving portion extends over an entire width of the flat heat exchange tube. Thereby the heat exchange tube, installed frontally or reversely, can ensure that there is the stress relieving section in the areas subjected to thermal loads or dynamic loads. In this way, the step of determining the installation direction of the heat exchange tube can be omitted in the assembly process, which is conducive to the efficient mass production of heat exchange tubes and heat exchangers.

[0020] According to another aspect of the present invention, there is provided a construction machine comprising the heat exchanger described above.

[0021] Advantageously, the heat exchanger is an engine charge air cooler or a compressor charge air cooler.

[0022] With a stress relieving portion arranged on the heat exchange tube, the heat exchanger according to the present invention advantageously slows down the thermal expansion of the heat exchange tube in the length direction and the thickness direction and enhances its structural strength in the width direction. In addition, the floating tube sheets provide constraints on the displacement of the heat exchange tubes and the whole heat exchange core, which not only guides the deformation and displacement of the heat exchange tubes, but also enhances the overall strength of the heat exchange tube bundle. Flexible fillers are provided to absorb the loads transferred between the floating tube sheet, the heat exchange tubes and the fixed tube sheet, which provides good buffer and protection for the tubes, the tube sheets, and the connection therebetween. Moreover, the flat heat exchange tube of the heat exchanger in the present invention is made of steel, which is conducive to decreasing the heat exchanger product in size and weight while maintaining the same performance, and assembling by directly adopting the brazing process, so as to improve the assembly efficiency and reduce the costs. Owing to the above-mentioned materials and structural design, the heat exchanger of the present invention can be applied to diversified application scenarios, for example, to diesel engine charge air coolers or to gas engine charge air coolers.BRIEF DESCRIPTION OF DRAWINGS

[0023] Features and advantages of an example of the present invention will become apparent with reference to the following detailed description and drawings.

[0024] FIG. 1 is an overall schematic diagram of a heat exchanger according to the present invention, in which fins are not shown to clearly show the layout of flat heat exchange tubes;

[0025] FIG. 2 is a schematic cross-sectional view of the heat exchanger shown in FIG. 1 cut along a line A-A;

[0026] FIG. 3 is an enlarged schematic view of the lower right part of FIG. 2;

[0027] FIG. 4 is an enlarged schematic view of a part of FIG. 3; and

[0028] FIG. 5 is a schematic view of the part shown in FIG. 4 after removing the fixed tube sheet.LIST OF REFERENCE SIGNS

[0029] 1—heat exchanger; 10—heat exchange core; 100—flat heat exchange tube; 11—first header box; 12—second header box; 13—fixed tube sheet; 14—tube sheet frame; 101—stress relieving portion; 100a—first planar wall portion; 100b—second planar wall portion; 100c—side wall portion; 101a—first corrugated section; 101b—second corrugated section; 15—floating tube sheet; 11i—inlet; 12o—outlet; L—length direction; W—width direction; T—thickness direction; CL—longitudinal direction of corrugated section; AD—air inflow direction; G—gap.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In order that those skilled in the art can better understand the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part instead of the whole of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without exerting any creative effort should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms “comprising”, “including” and “having” and any variation thereof in the description, claims, and accompanying drawings of the present invention are intended to mean non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the explicitly listed steps or units, but may include other steps or units not explicitly listed or inherent to the process, method, product or device.

[0032] The terms “first”, “second” and so on are introduced in the description of the present invention for descriptive purposes only, and cannot be understood as indicating or implying relative importance. The orientation or positional relationship indicated by the orientation words “top”, “bottom”, “upper” and “lower” is based on the orientation or positional relationship shown in the accompanying drawings.

[0033] With reference to FIG. 1, a heat exchanger 1 in the present invention includes a heat exchange core 10 and header boxes arranged at both ends of the heat exchange core. The heat exchange core 10 includes a plurality of flat heat exchange tubes 100 arranged up and down in parallel, and fins (not shown) arranged between the flat heat exchange tubes. First open ends of the flat heat exchange tubes 100 are connected to a first header box 11 to form fluid communication with internal space of the first header box. Second open ends of the flat heat exchange tubes 100 are connected to a second header box 12 to form fluid communication with internal space of the second header box.

[0034] Referring to FIGS. 2 and 3, two open ends of each flat heat exchange tube 100 pass through the holes formed on the fixed tube sheet 13 and extend to interiors of respective header boxes to form communication therewith. The fixed tube sheet 13 is fixedly connected to the corresponding header box. In the illustrated embodiment, a peripheral side of the fixed tube sheet is fixedly connected to an inner peripheral wall of a tube sheet frame 14 in a sealed manner. The tube sheet frame 14 is detachably connected to a side of the header box facing the heat exchange core 10. It will be appreciated that the tube sheet frame can also be designed as an integral extension of the header box extending in a direction towards the heat exchange core. The tube sheet frame 14 is arranged to surround an end section of the heat exchange core 10. The flat heat exchange tube 100 of the heat exchange core 10 is fixedly connected to the fixed tube sheet 13 in a sealed manner by brazing. Therefore, the position where the flat heat exchange tube 100 is engaged with an inner wall of the hole on the fixed tube sheet 13 is the mounting position of the flat heat exchange tube. For each flat heat exchange tube, its mounting position is located in the end region at a position where the tube is engaged within the hole of the fixed tube sheet.

[0035] In the heat exchanger according to the present invention, the flat heat exchange tube 100 is provided with a stress relieving portion 101 for relieving the stress of the tube wall. The stress relieving portion 101 is located on a side of the fixed tube sheet 13 that is away from the corresponding header box.

[0036] As can be seen from FIG. 2 and FIGS. 3-5, the flat heat exchange tube 100 comprises planar wall portions extending in a length direction L and a width direction W of the heat exchange tube and spaced apart from each other in a thickness direction T of the heat exchange tube, and side wall portions extending in length and thickness directions of the heat exchange tube across side edges of the planar wall portions (see FIG. 2, which only shows a side wall portion 100c located at a rear end in a fore-and-aft direction of the heat exchanger). Opposite planar wall portions and opposite side wall portions form a conduit with a flat cavity. The flat cavity defines a passage through which a working fluid flows. Working fluid from, for example, the first header box flows through the flat cavity to the second header box. In an embodiment of the present invention, at least one planar wall portion of the flat heat exchange tube is provided with the stress relieving portion in an area close to its mounting position. In the illustrated embodiment, the stress relieving portion 101 is implemented to include one or more elongated corrugated sections formed by local arching or recessing of the planar wall portion, a longitudinal direction CL of the corrugated section being substantially identical with the width direction of the heat exchange tube (see FIG. 5 for details).

[0037] Referring to FIGS. 4 and 5, a first corrugated section 101a is formed on a first planar wall portion 100a (an upper planar wall portion) of the flat heat exchange tube 100, and a second corrugated section 101b is formed on a second planar wall portion 100b (a lower planar wall portion) of the flat heat exchange tube opposite to the first planar wall portion. The first and second corrugated sections are implemented as convex strips arched toward outside of the heat exchange tube. The first corrugated section bulges in a first direction (in an upward thickness direction) relative to a plane where the first planar wall portion is located, and the second corrugated section bulges in a second direction (in a downward thickness direction) relative to a plane where the second planar wall portion is located, wherein the first direction is opposite to the second direction. The first corrugated section and the second corrugated section may be positioned opposite to each other in the thickness direction of the flat heat exchange tube. Advantageously, outer side edges of the first and second corrugated sections in the length direction of the flat heat exchange tube fall in a same vertical plane, thereby facilitating the positioning and installation of the fixed tube sheet. Therefore, seen from a longitudinal section of the flat heat exchange tube, in an area close to the mounting position, the stress relieving portion 101 can provide sufficient deformable expansion to ensure that the deformation or displacement of the planar wall portion of the flat heat exchange tube caused by installation or expansion stress is within a controllable range, thus avoiding tube wall fracture and possible fluid leakage.

[0038] While the first and second corrugated sections are shown as convex strips in the illustrated embodiment, it will be appreciated that the stress relieving portion can be designed in a corrugated structure with a plurality of peaks or valleys.

[0039] In the heat exchanger according to the present invention, a floating tube sheet 15 is arranged at a distance from the fixed tube sheet on the side of the fixed tube sheet 13 away from the header box. A peripheral side of the floating tube sheet 15 faces the inner peripheral wall of the tube sheet frame 14 and maintains a predetermined gap G with it. The flat heat exchange tube extends through a hole formed on the floating tube sheet 15 and is fixedly connected with it. Because the floating tube sheet 15 is not fixedly connected with the tube sheet frame 14, it provides some guidance for the deformation of the flat heat exchange tube 100 in the length direction, the width direction and the thickness direction, ensures that the deformation or displacement of the tube wall of the flat heat exchange tube is within a controllable range, and restricts the overall displacement of a single tube and the heat exchange core. Therefore, it can absorb part of the thermal stress and effectively reduce the stress or load transmitted to the fixed tube sheet. In addition, the floating tube sheet 15 and the fixed tube sheet 13 arranged in pairs hereinabove are conducive to good sealing between the tube and the tube sheet and between the tube sheet and the tube sheet frame 14.

[0040] In an illustrated advantageous embodiment, at least one stress relieving portion is arranged between paired floating tube sheet(s) 15 and fixed tube sheet(s) 13 in an area of the flat heat exchange tube adjacent to its mounting position. The stress relieving portion 101 may be disposed closer to the fixed tube sheet 13 than the floating tube sheet. Therefore, the stress relieving portion 101 provides strong protection for the sealed connection and fixed connection at the mounting position of the flat heat exchange tube.

[0041] In the heat exchanger according to the present invention, a flexible material (not shown) may be filled between the paired floating tube sheets 15 and fixed tube sheets 13 and between adjacent flat heat exchange tubes 100 to absorb loads acting on the floating or fixed tube sheets or the flat heat exchange tubes. The flexible material includes, for example, rubber or asphalt or a mixture thereof. During the operation of the heat exchanger, the loads acting on the floating or fixed tube sheets or the flat heat exchange tubes are mainly dynamic loads and / or thermal loads. Excessive dynamic and / or thermal load may lead to deformation of the tube wall of the heat exchange tube or deformation of the tube sheet, and hence failure of sealed connection. Therefore, these flexible fillers can absorb excessive loads, effectively protect the heat exchange tubes and tube sheets, and ensure that the deformation of the tube walls and tube sheets is always within a controllable range.

[0042] According to the present invention, there is provided a construction machine with the above-mentioned heat exchanger. The heat exchanger can be used as an engine charge air cooler or a compressor charge air cooler. In the charge air cooler, the fluid flowing through a fin gap is high-temperature air, and the fluid flowing through an internal channel of the flat heat exchange tube is low-temperature coolant.

[0043] In an embodiment of the present invention, the flat heat exchange tube 100 and fins may be made of stainless steel. Therefore, they can be used in occasions (e.g. on gas engines, compressors, etc.) where corrosive medium fluids are used. Stainless steel is also conducive to improving the heat transfer performance and reducing the weight of the material and the size of the tube. In addition, it facilities manufacturing with the brazing process to reduce the manufacturing time.

[0044] The floating and fixed tube sheets may be, for example, 1-3 mm thick steel plates made by punching. In the embodiment shown in FIGS. 2-3, the fixed tube sheet includes two juxtaposed steel plates to provide sufficient strength. To facilitate welding, the periphery of the fixed tube sheet is provided with an abutting flange, which makes the area of abutting with the inner peripheral wall of the tube sheet frame larger than before.

[0045] For example, in a case where the heat exchanger of the present invention is used as a charge air cooler, the air flow outside the tube has a high-temperature flushing part near the mounting position of the heat exchange tube. This part of high-temperature air flow has not yet exchanged heat with the cooling fluid flow in the tube, and will impose large dynamic and thermal loads on the joint between the tube and the fixed tube sheet. The stress relieving portion can be generally distributed in an area with extremely high dynamic or thermal load, that is, it can be designed to extend over a part of the width of the flat heat exchange tube. In order to facilitate mass production and simplify the installation process, the stress relieving portion can also be set to extend over the entire width of the flat heat exchange tube. In order to improve the assembly efficiency, the stress relieving portions and / or floating tube sheets on both ends of the flat heat exchange tube can also be set mirror symmetrical with respect to a central vertical section of the heat exchange core.

[0046] In an illustrated embodiment, both ends of the flat heat exchange tube are provided with stress relieving portions, the structures of which are basically the same, and floating tube sheets are provided at sides of the stress relieving portion away from the fixed tube sheets. It will be appreciated that according to the specific flow channel design of high-temperature air flow, only one end of the heat exchange core is provided with the floating tube sheet or the stress relieving portion.Industrial Applicability

[0047] In order to facilitate the understanding of the present invention, the installation process and working principle of the heat exchanger illustrated in the present invention are described below:

[0048] A plurality of flat heat exchange tubes made of stainless steel are provided, and stress relieving portions are arranged on two opposite planar wall portions at both ends of the heat exchange tube. The heat exchange tubes are installed on a floating tube sheet made of stainless steel (the floating tube sheet can be composed of two halves) at predetermined intervals. At the same time, stainless steel fins are placed between the heat exchange tubes. After the floating tube sheet is assembled, fixed tube sheets made of stainless steel are installed at both ends of the heat exchange tube, and flexible material is filled between the floating tube sheet and the fixed tube sheet, and then the fixed tube sheets are assembled into the tube sheet frame. Solder is applied between the heat exchange tubes and the fins, between the floating tube sheet and the heat exchange tubes, and between the abutting flange of the fixed tube sheet and the inner wall of the tube sheet frame. All the parts where solder is applied are connected by the brazing process to create an entire heat exchange core. Next, the tube sheet frames at both ends are fixedly connected to the header boxes and top and bottom plates covering a top row of heat exchange fins and a bottom row of heat exchange fins. In this way, an entire heat exchanger is formed.

[0049] As shown in FIGS. 1 and 2, the charge air flow to be cooled enters the heat exchanger along the air inflow direction AD. The coolant enters the header box from an inlet 11i of the first header box 11, branches into respective flat heat exchange tubes, exchanges heat with the air flow outside the tube when flowing through the heat exchange tube, and then enters the second header box 12 and is discharged from an outlet 12o of the second header box.

[0050] Therefore, in the connection area between the tube and the tube sheet, the part closest to the incoming charge air is subjected to a larger thermal load and dynamic load. Under the action of the stress relieving portion, the floating tube sheet and the flexible filler, the load finally transmitted to the joint between the tube and the fixed tube sheet is substantially reduced, ensuring the integrity of the heat exchange tube and the robustness and airtightness of the connection between the tube and the fixed tube sheet.

[0051] Exemplary embodiments according to the present invention are described hereinabove, but the method and device are not limited to the specific embodiments described herein. “An example”, “another example”, “examples”, and the like mentioned throughout the specification are intended to describe that a certain member / element (such as feature, structure, and / or characteristic) associated with the example is included in at least one example described herein and may or may not appear in other examples. In addition, it will be appreciated that multiple elements in any example described herein may be combined in any suitable manner in multiple different examples, unless otherwise explicitly stated in the context.

[0052] In the specification, the invention is disclosed by way of examples, including the optimal embodiment, which enables any person skilled in the art to implement the present invention. The patentable scope of the present invention is defined by the claims, and may include other examples that may occur to those skilled in the art. If these other examples include structural elements that are not distinguishable from those described in the literal language of the claims, or if they include equivalent structural elements that are not substantially distinguishable from those described in the literal language of the claims, then they should fall within the scope of the claims.

Examples

Embodiment Construction

[0030]In order that those skilled in the art can better understand the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part instead of the whole of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without exerting any creative effort should fall within the scope of protection of the present invention.

[0031]It should be noted that the terms “comprising”, “including” and “having” and any variation thereof in the description, claims, and accompanying drawings of the present invention are intended to mean non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the explicitly listed steps or units, but may include other steps or units...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of and claims priority to prior application Ser. No. 19 / 278,999, filed Jul. 24, 2025 which claims priority to Chinese Patent Application Number 202411048905.6, filed Jul. 31, 2024, which are hereby incorporated by reference in their entirety.TECHNICAL FIELD

[0002] The present invention relates to the technical field of heat dissipation, in particular to a flat heat exchange tube, a heat exchanger for a construction machine and a construction machine comprising the heat exchanger.BACKGROUND ART

[0003] In construction machinery, in order to improve engine power and reduce fuel consumption, a charge air cooler is usually provided to cool, by a coolant, the charge air intended for the engine. Specific applications include engine charge air coolers and compressor charge air coolers. As a charge air cooler, the heat exchanger is usually designed in a tube-fin form, including heat exchange tubes and heat exchange fins. The heat exchange fins and heat exchange tubes are usually connected by an expansion joint process, so are the heat exchange tubes and end tube sheets. The heat exchange tubes and heat exchange fins are usually made of copper. For example, since the charge air cooler for a gas engine uses corrosive medium, the heat exchanger is usually made of stainless steel. This tube-fin design has the following defects: 1) the effective heat exchange area has a low utilization rate, and there is a contact gap between heat exchange elements, which leads to a high thermal resistance and thus a low heat exchange performance; 2) it entails high material costs, a complicated manufacturing process and high labor costs; 3) the stainless steel tube has difficulty in expansion joint, leading to high costs; 4) it has a low production efficiency, not suitable for mass production; 5) hundreds of heat exchange tubes need to be expanded, and it is difficult to control the quality of expansion; 6) mechanical stress and thermal stress are concentrated in the area of expansion joint between the heat exchange tube and the end tube sheet, which makes the tube or tube sheet fracture easily, leading to leakage.

[0004] Accordingly, the present invention aims to overcome one or more of the above problems.SUMMARY OF THE INVENTION

[0005] With respect to the above problems, the present invention proposes an improved flat heat exchange tube and a heat exchanger comprising said flat heat exchange tube, which greatly improves the manufacturing and assembly efficiency, enhances the heat exchange efficiency, ensures the stability of product quality and the reliability of product operation, reduces the manufacturing cost and material cost, and decreases the product in both weight and size.

[0006] According to an aspect of the present invention, there is provided a flat heat exchange tube. The flat heat exchange tube comprises: planar wall portions extending in length and width directions of the heat exchange tube and spaced apart from each other in a thickness direction of the heat exchange tube, and side wall portions extending in length and thickness directions of the heat exchange tube across side edges of the planar wall portions, wherein at least one planar wall portion of the flat heat exchange tube is provided, in an area adjacent to its mounting position, with a stress relieving portion for relieving stress of tube wall, the stress relieving portion comprising one or more elongated corrugated sections formed by local arching or recessing of the planar wall portion, and a longitudinal direction of the corrugated section being substantially identical with the width direction of the heat exchange tube.

[0007] The corrugated feature of the flat heat exchange tube according to the present invention can be directly formed by a stamping process when the tube is manufactured, leading to a high manufacturing efficiency and low costs. This corrugated feature plays an important role in stress mitigation in the subsequent assembly process and operation process, especially in some areas close to the mounting position of the heat exchange tube (the areas where high-temperature and high-pressure pressurized air enters the heat exchange tube but does not exchange heat with the coolant therein), so as to alleviate stress concentration and ensure the stability of product quality and the reliability of heat exchanger operation. There is a large joint area between the flat heat exchange tube and the fin, which is beneficial to reducing the thermal resistance between the heat exchange tube and the fin and improving the heat exchange efficiency. Under the same heat exchange requirements, the heat exchanger can be designed smaller in size and therefore weight.

[0008] In an advantageous embodiment, a first corrugated section is formed on a first planar wall portion of the flat heat exchange tube, and a second corrugated section is formed on a second planar wall portion of the flat heat exchange tube opposite to the first planar wall portion. This can advantageously cope with the situation where the upper and lower planar wall portions of the flat heat exchange tube are subjected to different stresses. The flat heat exchange tube according to the present invention has better stress adaptability and therefore expanded application scenarios.

[0009] In an advantageous embodiment, the first corrugated section bulges in a first direction relative to a plane where the first planar wall portion is located, and the second corrugated section bulges in a second direction relative to a plane where the second planar wall portion is located, wherein the first direction is opposite to the second direction.

[0010] In an advantageous embodiment, the first and second corrugated sections are positioned opposite to each other in the thickness direction of the flat heat exchange tube. This is beneficial to the assembly and positioning of the heat exchange tube to the tube sheet.

[0011] In an advantageous embodiment, the first and second corrugated sections are convex strips arched toward outside of the heat exchange tube. In this configuration, the cross-section of the fluid in the tube is enlarged, and the high-temperature and high-pressure air is branched under the action of the convex strips, which is beneficial to reducing the mechanical stress acting on the tube and the tube sheet. In addition, due to the inherent deformable potential, the convex strip can absorb some inherent mechanical stress on the tube or tube sheet, which can advantageously ensure the quality of the tube and tube sheet and of the connection therebetween, as well as the sealing integrity.

[0012] In an advantageous embodiment, the flat heat exchange tube is made of stainless steel. Thereby the heat exchange tube and the heat exchanger with the heat exchange tube can be applied to more scenarios. Stainless steel is more conducive to the implementation of brazing, thus making the assembly efficiency greatly improved.

[0013] According to another aspect of the present invention, there is provided a heat exchanger for construction machinery. The heat exchanger comprises: a heat exchange core, the heat exchange core comprising: a plurality of flat heat exchange tubes and fins arranged therebetween; a first header box connected to one end of each of the flat heat exchange tubes; and a second header box connected to the other end of each of the flat heat exchange tubes, wherein the flat heat exchange tube is the aforementioned flat heat exchange tube, each of the flat heat exchange tubes is installed to a corresponding header box in such a way that its open end passes through a hole formed on a fixed tube sheet fixedly connected to the corresponding header box and communicates with an interior of the corresponding header box, and the stress relieving portion arranged adjacent to the mounting position is located at a side of the fixed tube sheet away from the corresponding header box.

[0014] In an advantageous embodiment, each of the flat heat exchange tubes is fixedly connected to the fixed tube sheet in a sealed manner by brazing. Compared with the existing expansion joint process, the brazing process has high efficiency and guarantees quality and reliability.

[0015] In an advantageous embodiment, the heat exchanger comprises a tube sheet frame integrally or detachably connected to the header box, and a peripheral side of the fixed tube sheet is fixedly connected with an inner peripheral wall of the tube sheet frame in a sealed manner.

[0016] In an advantageous embodiment, the heat exchanger comprises a floating tube sheet arranged at a distance from the fixed tube sheet and on the side of the fixed tube sheet away from the header box, and a peripheral side of the floating tube sheet faces the inner peripheral wall of the tube sheet frame and maintains a predetermined gap with it, and the flat heat exchange tubes extend through holes of the floating tube sheet and are fixedly connected with it. The arrangement of the floating tube sheet is conducive to guiding the deformation of the planar wall portion of the flat heat exchange tube or endowing it with certain constraint variables, and absorbing some loads or stresses acting on the heat exchange tube and the tube sheet.

[0017] In an advantageous embodiment, at least one stress relieving portion is arranged between paired floating tube sheet and fixed tube sheet in an area of the flat heat exchange tube adjacent to its mounting position. In this way, the floating tube sheet provides protection for the stress relieving portion. When the dynamic load or thermal load is too large, the floating tube sheet can reduce the impact on the stress relieving portion through part of its own deformation, and the stress relieving portion can absorb the remaining load through deformation, thus ensuring that the load on the connection area between the tube and the tube sheet is within a controllable range. Therefore, the structure providing layer-by-layer protection is conducive to improving the operational stability and reliability of the heat exchanger.

[0018] In an advantageous embodiment, flexible material is filled between the paired floating tube sheet and fixed tube sheet and between adjacent flat heat exchange tubes to absorb loads acting on the floating or fixed tube sheet or the flat heat exchange tubes. Advantageously, the flexible material comprises rubber or asphalt. The arrangement of the flexible filler is conducive to ensuring that most of the loads acting on or transmitted from the heat exchange tubes or tube sheets are absorbed to provide a buffering effect for the rigid tubes and tube sheets, and ensuring that the deformation of the tubes and tube sheets is kept as small as possible or almost at a zero level.

[0019] In an advantageous embodiment, the stress relieving portion extends over an entire width of the flat heat exchange tube. Thereby the heat exchange tube, installed frontally or reversely, can ensure that there is the stress relieving section in the areas subjected to thermal loads or dynamic loads. In this way, the step of determining the installation direction of the heat exchange tube can be omitted in the assembly process, which is conducive to the efficient mass production of heat exchange tubes and heat exchangers.

[0020] According to another aspect of the present invention, there is provided a construction machine comprising the heat exchanger described above.

[0021] Advantageously, the heat exchanger is an engine charge air cooler or a compressor charge air cooler.

[0022] With a stress relieving portion arranged on the heat exchange tube, the heat exchanger according to the present invention advantageously slows down the thermal expansion of the heat exchange tube in the length direction and the thickness direction and enhances its structural strength in the width direction. In addition, the floating tube sheets provide constraints on the displacement of the heat exchange tubes and the whole heat exchange core, which not only guides the deformation and displacement of the heat exchange tubes, but also enhances the overall strength of the heat exchange tube bundle. Flexible fillers are provided to absorb the loads transferred between the floating tube sheet, the heat exchange tubes and the fixed tube sheet, which provides good buffer and protection for the tubes, the tube sheets, and the connection therebetween. Moreover, the flat heat exchange tube of the heat exchanger in the present invention is made of steel, which is conducive to decreasing the heat exchanger product in size and weight while maintaining the same performance, and assembling by directly adopting the brazing process, so as to improve the assembly efficiency and reduce the costs. Owing to the above-mentioned materials and structural design, the heat exchanger of the present invention can be applied to diversified application scenarios, for example, to diesel engine charge air coolers or to gas engine charge air coolers.BRIEF DESCRIPTION OF DRAWINGS

[0023] Features and advantages of an example of the present invention will become apparent with reference to the following detailed description and drawings.

[0024] FIG. 1 is an overall schematic diagram of a heat exchanger according to the present invention, in which fins are not shown to clearly show the layout of flat heat exchange tubes;

[0025] FIG. 2 is a schematic cross-sectional view of the heat exchanger shown in FIG. 1 cut along a line A-A;

[0026] FIG. 3 is an enlarged schematic view of the lower right part of FIG. 2;

[0027] FIG. 4 is an enlarged schematic view of a part of FIG. 3; and

[0028] FIG. 5 is a schematic view of the part shown in FIG. 4 after removing the fixed tube sheet.LIST OF REFERENCE SIGNS

[0029] 1—heat exchanger; 10—heat exchange core; 100—flat heat exchange tube; 11—first header box; 12—second header box; 13—fixed tube sheet; 14—tube sheet frame; 101—stress relieving portion; 100a—first planar wall portion; 100b—second planar wall portion; 100c—side wall portion; 101a—first corrugated section; 101b—second corrugated section; 15—floating tube sheet; 11i—inlet; 12o—outlet; L—length direction; W—width direction; T—thickness direction; CL—longitudinal direction of corrugated section; AD—air inflow direction; G—gap.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] In order that those skilled in the art can better understand the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part instead of the whole of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without exerting any creative effort should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms “comprising”, “including” and “having” and any variation thereof in the description, claims, and accompanying drawings of the present invention are intended to mean non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the explicitly listed steps or units, but may include other steps or units not explicitly listed or inherent to the process, method, product or device.

[0032] The terms “first”, “second” and so on are introduced in the description of the present invention for descriptive purposes only, and cannot be understood as indicating or implying relative importance. The orientation or positional relationship indicated by the orientation words “top”, “bottom”, “upper” and “lower” is based on the orientation or positional relationship shown in the accompanying drawings.

[0033] With reference to FIG. 1, a heat exchanger 1 in the present invention includes a heat exchange core 10 and header boxes arranged at both ends of the heat exchange core. The heat exchange core 10 includes a plurality of flat heat exchange tubes 100 arranged up and down in parallel, and fins (not shown) arranged between the flat heat exchange tubes. First open ends of the flat heat exchange tubes 100 are connected to a first header box 11 to form fluid communication with internal space of the first header box. Second open ends of the flat heat exchange tubes 100 are connected to a second header box 12 to form fluid communication with internal space of the second header box.

[0034] Referring to FIGS. 2 and 3, two open ends of each flat heat exchange tube 100 pass through the holes formed on the fixed tube sheet 13 and extend to interiors of respective header boxes to form communication therewith. The fixed tube sheet 13 is fixedly connected to the corresponding header box. In the illustrated embodiment, a peripheral side of the fixed tube sheet is fixedly connected to an inner peripheral wall of a tube sheet frame 14 in a sealed manner. The tube sheet frame 14 is detachably connected to a side of the header box facing the heat exchange core 10. It will be appreciated that the tube sheet frame can also be designed as an integral extension of the header box extending in a direction towards the heat exchange core. The tube sheet frame 14 is arranged to surround an end section of the heat exchange core 10. The flat heat exchange tube 100 of the heat exchange core 10 is fixedly connected to the fixed tube sheet 13 in a sealed manner by brazing. Therefore, the position where the flat heat exchange tube 100 is engaged with an inner wall of the hole on the fixed tube sheet 13 is the mounting position of the flat heat exchange tube. For each flat heat exchange tube, its mounting position is located in the end region at a position where the tube is engaged within the hole of the fixed tube sheet.

[0035] In the heat exchanger according to the present invention, the flat heat exchange tube 100 is provided with a stress relieving portion 101 for relieving the stress of the tube wall. The stress relieving portion 101 is located on a side of the fixed tube sheet 13 that is away from the corresponding header box.

[0036] As can be seen from FIG. 2 and FIGS. 3-5, the flat heat exchange tube 100 comprises planar wall portions extending in a length direction L and a width direction W of the heat exchange tube and spaced apart from each other in a thickness direction T of the heat exchange tube, and side wall portions extending in length and thickness directions of the heat exchange tube across side edges of the planar wall portions (see FIG. 2, which only shows a side wall portion 100c located at a rear end in a fore-and-aft direction of the heat exchanger). Opposite planar wall portions and opposite side wall portions form a conduit with a flat cavity. The flat cavity defines a passage through which a working fluid flows. Working fluid from, for example, the first header box flows through the flat cavity to the second header box. In an embodiment of the present invention, at least one planar wall portion of the flat heat exchange tube is provided with the stress relieving portion in an area close to its mounting position. In the illustrated embodiment, the stress relieving portion 101 is implemented to include one or more elongated corrugated sections formed by local arching or recessing of the planar wall portion, a longitudinal direction CL of the corrugated section being substantially identical with the width direction of the heat exchange tube (see FIG. 5 for details).

[0037] Referring to FIGS. 4 and 5, a first corrugated section 101a is formed on a first planar wall portion 100a (an upper planar wall portion) of the flat heat exchange tube 100, and a second corrugated section 101b is formed on a second planar wall portion 100b (a lower planar wall portion) of the flat heat exchange tube opposite to the first planar wall portion. The first and second corrugated sections are implemented as convex strips arched toward outside of the heat exchange tube. The first corrugated section bulges in a first direction (in an upward thickness direction) relative to a plane where the first planar wall portion is located, and the second corrugated section bulges in a second direction (in a downward thickness direction) relative to a plane where the second planar wall portion is located, wherein the first direction is opposite to the second direction. The first corrugated section and the second corrugated section may be positioned opposite to each other in the thickness direction of the flat heat exchange tube. Advantageously, outer side edges of the first and second corrugated sections in the length direction of the flat heat exchange tube fall in a same vertical plane, thereby facilitating the positioning and installation of the fixed tube sheet. Therefore, seen from a longitudinal section of the flat heat exchange tube, in an area close to the mounting position, the stress relieving portion 101 can provide sufficient deformable expansion to ensure that the deformation or displacement of the planar wall portion of the flat heat exchange tube caused by installation or expansion stress is within a controllable range, thus avoiding tube wall fracture and possible fluid leakage.

[0038] While the first and second corrugated sections are shown as convex strips in the illustrated embodiment, it will be appreciated that the stress relieving portion can be designed in a corrugated structure with a plurality of peaks or valleys.

[0039] In the heat exchanger according to the present invention, a floating tube sheet 15 is arranged at a distance from the fixed tube sheet on the side of the fixed tube sheet 13 away from the header box. A peripheral side of the floating tube sheet 15 faces the inner peripheral wall of the tube sheet frame 14 and maintains a predetermined gap G with it. The flat heat exchange tube extends through a hole formed on the floating tube sheet 15 and is fixedly connected with it. Because the floating tube sheet 15 is not fixedly connected with the tube sheet frame 14, it provides some guidance for the deformation of the flat heat exchange tube 100 in the length direction, the width direction and the thickness direction, ensures that the deformation or displacement of the tube wall of the flat heat exchange tube is within a controllable range, and restricts the overall displacement of a single tube and the heat exchange core. Therefore, it can absorb part of the thermal stress and effectively reduce the stress or load transmitted to the fixed tube sheet. In addition, the floating tube sheet 15 and the fixed tube sheet 13 arranged in pairs hereinabove are conducive to good sealing between the tube and the tube sheet and between the tube sheet and the tube sheet frame 14.

[0040] In an illustrated advantageous embodiment, at least one stress relieving portion is arranged between paired floating tube sheet(s) 15 and fixed tube sheet(s) 13 in an area of the flat heat exchange tube adjacent to its mounting position. The stress relieving portion 101 may be disposed closer to the fixed tube sheet 13 than the floating tube sheet. Therefore, the stress relieving portion 101 provides strong protection for the sealed connection and fixed connection at the mounting position of the flat heat exchange tube.

[0041] In the heat exchanger according to the present invention, a flexible material (not shown) may be filled between the paired floating tube sheets 15 and fixed tube sheets 13 and between adjacent flat heat exchange tubes 100 to absorb loads acting on the floating or fixed tube sheets or the flat heat exchange tubes. The flexible material includes, for example, rubber or asphalt or a mixture thereof. During the operation of the heat exchanger, the loads acting on the floating or fixed tube sheets or the flat heat exchange tubes are mainly dynamic loads and / or thermal loads. Excessive dynamic and / or thermal load may lead to deformation of the tube wall of the heat exchange tube or deformation of the tube sheet, and hence failure of sealed connection. Therefore, these flexible fillers can absorb excessive loads, effectively protect the heat exchange tubes and tube sheets, and ensure that the deformation of the tube walls and tube sheets is always within a controllable range.

[0042] According to the present invention, there is provided a construction machine with the above-mentioned heat exchanger. The heat exchanger can be used as an engine charge air cooler or a compressor charge air cooler. In the charge air cooler, the fluid flowing through a fin gap is high-temperature air, and the fluid flowing through an internal channel of the flat heat exchange tube is low-temperature coolant.

[0043] In an embodiment of the present invention, the flat heat exchange tube 100 and fins may be made of stainless steel. Therefore, they can be used in occasions (e.g. on gas engines, compressors, etc.) where corrosive medium fluids are used. Stainless steel is also conducive to improving the heat transfer performance and reducing the weight of the material and the size of the tube. In addition, it facilities manufacturing with the brazing process to reduce the manufacturing time.

[0044] The floating and fixed tube sheets may be, for example, 1-3 mm thick steel plates made by punching. In the embodiment shown in FIGS. 2-3, the fixed tube sheet includes two juxtaposed steel plates to provide sufficient strength. To facilitate welding, the periphery of the fixed tube sheet is provided with an abutting flange, which makes the area of abutting with the inner peripheral wall of the tube sheet frame larger than before.

[0045] For example, in a case where the heat exchanger of the present invention is used as a charge air cooler, the air flow outside the tube has a high-temperature flushing part near the mounting position of the heat exchange tube. This part of high-temperature air flow has not yet exchanged heat with the cooling fluid flow in the tube, and will impose large dynamic and thermal loads on the joint between the tube and the fixed tube sheet. The stress relieving portion can be generally distributed in an area with extremely high dynamic or thermal load, that is, it can be designed to extend over a part of the width of the flat heat exchange tube. In order to facilitate mass production and simplify the installation process, the stress relieving portion can also be set to extend over the entire width of the flat heat exchange tube. In order to improve the assembly efficiency, the stress relieving portions and / or floating tube sheets on both ends of the flat heat exchange tube can also be set mirror symmetrical with respect to a central vertical section of the heat exchange core.

[0046] In an illustrated embodiment, both ends of the flat heat exchange tube are provided with stress relieving portions, the structures of which are basically the same, and floating tube sheets are provided at sides of the stress relieving portion away from the fixed tube sheets. It will be appreciated that according to the specific flow channel design of high-temperature air flow, only one end of the heat exchange core is provided with the floating tube sheet or the stress relieving portion.Industrial Applicability

[0047] In order to facilitate the understanding of the present invention, the installation process and working principle of the heat exchanger illustrated in the present invention are described below:

[0048] A plurality of flat heat exchange tubes made of stainless steel are provided, and stress relieving portions are arranged on two opposite planar wall portions at both ends of the heat exchange tube. The heat exchange tubes are installed on a floating tube sheet made of stainless steel (the floating tube sheet can be composed of two halves) at predetermined intervals. At the same time, stainless steel fins are placed between the heat exchange tubes. After the floating tube sheet is assembled, fixed tube sheets made of stainless steel are installed at both ends of the heat exchange tube, and flexible material is filled between the floating tube sheet and the fixed tube sheet, and then the fixed tube sheets are assembled into the tube sheet frame. Solder is applied between the heat exchange tubes and the fins, between the floating tube sheet and the heat exchange tubes, and between the abutting flange of the fixed tube sheet and the inner wall of the tube sheet frame. All the parts where solder is applied are connected by the brazing process to create an entire heat exchange core. Next, the tube sheet frames at both ends are fixedly connected to the header boxes and top and bottom plates covering a top row of heat exchange fins and a bottom row of heat exchange fins. In this way, an entire heat exchanger is formed.

[0049] As shown in FIGS. 1 and 2, the charge air flow to be cooled enters the heat exchanger along the air inflow direction AD. The coolant enters the header box from an inlet 11i of the first header box 11, branches into respective flat heat exchange tubes, exchanges heat with the air flow outside the tube when flowing through the heat exchange tube, and then enters the second header box 12 and is discharged from an outlet 12o of the second header box.

[0050] Therefore, in the connection area between the tube and the tube sheet, the part closest to the incoming charge air is subjected to a larger thermal load and dynamic load. Under the action of the stress relieving portion, the floating tube sheet and the flexible filler, the load finally transmitted to the joint between the tube and the fixed tube sheet is substantially reduced, ensuring the integrity of the heat exchange tube and the robustness and airtightness of the connection between the tube and the fixed tube sheet.

[0051] Exemplary embodiments according to the present invention are described hereinabove, but the method and device are not limited to the specific embodiments described herein. “An example”, “another example”, “examples”, and the like mentioned throughout the specification are intended to describe that a certain member / element (such as feature, structure, and / or characteristic) associated with the example is included in at least one example described herein and may or may not appear in other examples. In addition, it will be appreciated that multiple elements in any example described herein may be combined in any suitable manner in multiple different examples, unless otherwise explicitly stated in the context.

[0052] In the specification, the invention is disclosed by way of examples, including the optimal embodiment, which enables any person skilled in the art to implement the present invention. The patentable scope of the present invention is defined by the claims, and may include other examples that may occur to those skilled in the art. If these other examples include structural elements that are not distinguishable from those described in the literal language of the claims, or if they include equivalent structural elements that are not substantially distinguishable from those described in the literal language of the claims, then they should fall within the scope of the claims.

Examples

Embodiment Construction

[0030]In order that those skilled in the art can better understand the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part instead of the whole of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without exerting any creative effort should fall within the scope of protection of the present invention.

[0031]It should be noted that the terms “comprising”, “including” and “having” and any variation thereof in the description, claims, and accompanying drawings of the present invention are intended to mean non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the explicitly listed steps or units, but may include other steps or units...

Claims

1. A flat heat exchange tube, comprising: planar wall portions extending in length and width directions of the heat exchange tube and spaced apart from each other in a thickness direction of the heat exchange tube, and side wall portions extending in length and thickness directions of the heat exchange tube across side edges of the planar wall portions, wherein at least one planar wall portion of the flat heat exchange tube is provided, in an area adjacent to its mounting position, with a stress relieving portion for relieving stress of tube wall, the stress relieving portion comprising one or more elongated corrugated sections formed by local arching or recessing of the planar wall portion, and a longitudinal direction of the corrugated section being substantially identical with the width direction of the heat exchange tube.

2. The flat heat exchange tube according to claim 1, characterized in that a first corrugated section is formed on a first planar wall portion of the flat heat exchange tube, and a second corrugated section is formed on a second planar wall portion of the flat heat exchange tube opposite to the first planar wall portion.

3. The flat heat exchange tube according to claim 2, characterized in that the first corrugated section bulges in a first direction relative to a plane where the first planar wall portion is located, and the second corrugated section bulges in a second direction relative to a plane where the second planar wall portion is located, wherein the first direction is opposite to the second direction.

4. The flat heat exchange tube according to claim 3, characterized in that the first and second corrugated sections are positioned opposite to each other in the thickness direction of the flat heat exchange tube.

5. The flat heat exchange tube according to claim 4, characterized in that the first and second corrugated sections are convex strips arched toward outside of the heat exchange tube.

6. The flat heat exchange tube according to claim 1, characterized in that the flat heat exchange tube is made of stainless steel.

7. A heat exchanger for construction machinery, comprising: a heat exchange core, the heat exchange core comprising: a plurality of flat heat exchange tubes and fins arranged therebetween; a first header box connected to one end of each of the flat heat exchange tubes; and a second header box connected to the other end of each of the flat heat exchange tubes, wherein the flat heat exchange tube is the flat heat exchange tube according to claim 1, each of the flat heat exchange tubes is installed to a corresponding header box in such a way that its open end passes through a hole formed on a fixed tube sheet fixedly connected to the corresponding header box and communicates with an interior of the corresponding header box, and the stress relieving portion arranged adjacent to the mounting position is located at a side of the fixed tube sheet away from the corresponding header box.

8. The heat exchanger according to claim 7, characterized in that each of the flat heat exchange tubes is fixedly connected to the fixed tube sheet in a sealed manner by brazing.

9. The heat exchanger according to claim 8, characterized in that it comprises a tube sheet frame integrally or detachably connected to the header box, and a peripheral side of the fixed tube sheet is fixedly connected with an inner peripheral wall of the tube sheet frame in a sealed manner.

10. The heat exchanger according to claim 9, characterized in that the heat exchanger comprises a floating tube sheet arranged at a distance from the fixed tube sheet and on the side of the fixed tube sheet away from the header box, and a peripheral side of the floating tube sheet faces the inner peripheral wall of the tube sheet frame and maintains a predetermined gap with it, and the flat heat exchange tubes extend through holes of the floating tube sheet and are fixedly connected with it.

11. The heat exchanger according to claim 10, characterized in that at least one stress relieving portion is arranged between paired floating tube sheet and fixed tube sheet in an area of the flat heat exchange tube adjacent to its mounting position.

12. The heat exchanger according to claim 11, characterized in that flexible material is filled between the paired floating tube sheet and fixed tube sheet and between adjacent flat heat exchange tubes to absorb loads acting on the floating or fixed tube sheet or the flat heat exchange tubes.

13. The heat exchanger according to claim 12, characterized in that the flexible material comprises rubber or asphalt.

14. The heat exchanger according to claim 7, characterized in that the stress relieving portion extends over an entire width of the flat heat exchange tube.

15. A construction machine comprising the heat exchanger according to claim 7.

16. The construction machine according to claim 15, characterized in that the heat exchanger is an engine charge air cooler or a compressor charge air cooler.

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