A tube

Abstract

The object of the invention is, inter alia, a tube (1) for a high-pressure heat exchanger, the tube (1) comprising an axis of elongation (L1), a first main wall (4); a second main wall (5) parallel to the first main wall (4), each main wall (4, 5) comprising a substantially flat surface, and two complementary side walls (6) joining said main walls (4,5) together so as to define an outline of the tube (1), wherein the tube (1) comprises a with (W) measured between the outermost portions of the side walls (6) and perpendicularly with respect to axis of elongation (L1), wherein the tube (1) is divided into segments by at least one partition wall (100) extending between the main walls (4, 5) to form micro-channels (101), the micro-channels (101) extending in parallel to the axis of elongation (L1) of the tube (1), wherein the micro-channels (101) are configured to withstand burst pressure of at least 340 bar. Another object of the invention is a heat exchanger (1000) comprising such tube.

Description

[0001] A TUBE

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a tube. In particular, the invention relates to a tube for a heat exchanger.

[0004] BACKGROUND OF THE INVENTION

[0005] An extruded tubes are well-known in the art. Extruded tubes (hereafter: tubes) are usually used in automotive industry in the heat exchangers as competitive replacement for more classical, folded tubes. In the evolution of the automotive industry, in particular, the evolution of hybrid vehicles, electric vehicles, as well as vehicles having an internal combustion engine only, the extrusion process allows to provide robust elements which can withstand extreme conditions, compared to folded counterparts.

[0006] The tubes of this kind usually comprise multiple ports, called also micro-channels which allow the flow of the fluid therein.

[0007] Prior art tubes focus mainly on improving the tube structure against road conditions. The chipping of the tube during driving easily deforms or damages the front surfaces of the heat exchanger tubes. Further, during vehicle operation, the tubes are exposed to rainwater, mud, exhaust gas, refuse, etc. blown into the chassis from outside. These become causes of tube corrosion. In particular, corrosion is liable to occur starting from the deformed or damaged parts. The tubes therefore become corroded. If the corrosion progresses and holes form in the tubes, there is the problem of leakage of refrigerant.

[0008] The extrusion process sufficiently mitigates this problem in the tubes present in heat exchangers such as air gas coolers (AGC) outside heat exchangers (OHX), and other.

[0009] However, despite the extended lifetime of tubes, the customers set more and more strict requirements in terms of thermal performance of the tubes and the pressure drops. These requirements reflect on the heat exchangers comprising such tubes. This all serves to the right cause of providing more environmentally- friendly vehicles.

[0010] Thus, it is desired to provide a tube of improved thermal performance.

[0011] It is also desired to provide a tube which would improve the pressure drop factor.

[0012] It is also desired to provide the heat exchanger which would have increased performance.

[0013] It is also desired to provide the tube which would be able to withstand a very high pressure of the refrigerant flowing therein.

[0014] SUMMARY OF THE INVENTION

[0015] The object of the invention is, inter alia, a tube (1 ) for a high-pressure heat exchanger, the tube (1 ) comprising an axis of elongation (L1 ), a first main wall (4); a second main wall (5) parallel to the first main wall (4), each main wall (4, 5) comprising a substantially flat surface, and two complementary side walls (6) joining said main walls (4,5) together so as to define an outline of the tube (1 ), wherein the tube (1 ) comprises a with (W) measured between the outermost portions of the side walls (6) and perpendicularly with respect to axis of elongation (L1 ), wherein the tube (1 ) is divided into segments by at least one partition wall (100) extending between the main walls (4, 5) to form microchannels (101 ), the micro-channels (101 ) extending in parallel to the axis of elongation (L1 ) of the tube (1 ), wherein the micro-channels (101 ) are configured to withstand the burst pressure of at least 340 bar.

[0016] Advantageously, the tube (1 ) further comprises a height (H), the height (H) being measured between the main walls (4, 5) of the tube (1 ), a nose width (A) measured perpendicularly with respect to axis of elongation (L1 ) between the outermost portion of one of the side walls (6) and a portion of the neighboring micro-channel (101 ) which is located closest to said side wall (6), a main wall thickness (C) measured as an average distance between the portions of the micro-channels (101 ) located closest to the surface of the neighboring main wall (4,5) and the surface of said main wall (4, 5), the wall thickness being measured in perpendicular with respect to the width (W) and longitudinal axis (L1 ) of the tube (1 ), and wherein the partition wall (100) further comprises partition width (B) measured in parallel with respect to the width (W) between the walls forming the neighboring micro-channels (101 ).

[0017] Advantageously, the micro-channels (101 ) are in the shape of an oblong.

[0018] Advantageously, the height (H) of the tube is between 1 ,21 mm and 1 ,45mm.

[0019] Advantageously, a ratio between the nose width (A) and the partition width (B) is between 0,78 and 2,9.

[0020] Advantageously, a ratio between the partition width (B) and main wall thickness (C) is between 1 ,2 and 2,9.

[0021] Advantageously, the tube (1 ) comprises odd number of micro-channels (101 ).

[0022] Advantageously, the tube (1 ) comprises not less than 1 1 micro-channels (101 ) and not more than 17 micro-channels (101 ).

[0023] Advantageously, the micro-channels (101 ) are of substantially rectangular shape.

[0024] Advantageously, at least one micro-channel (101 ) located in the vicinity of side wall (6) comprises an arch-shaped portion (101 a), the arch-shaped portion (101 a) being arranged to imitate the outline of the side wall (6).

[0025] Advantageously, the height (H) of the tube (1 ) is between 1 ,20mm and 1 ,40mm.

[0026] Advantageously, a ratio between the nose width (A) and the partition width (B) is between 3,0 and 6,7.

[0027] Advantageously, a ratio between the partition width (B) and main wall thickness (C) is between 0,4 and 1 ,3.

[0028] Another object of the invention is a heat exchanger (1000) comprising at least one tube (1 ) according to any of the preceding claims.

[0029] Advantageously, the heat exchanger (1000) further comprises a pair of headers (1001 , 1002) spaced apart from each-other, the headers (1001 , 1002) comprising plurality of slots to accommodate the tubes (1 ), the tubes (1 ) along with the headers (1001 , 1002) being fluidly connected with each-other to provide a first fluid circuit. BRIEF DESCRITPTION OF DRAWINGS

[0030] Examples of the invention will be apparent from and described in detail with reference to the accompanying drawings, in which:

[0031] Fig. 1 shows a perspective view of the tube with oblong micro-channels.

[0032] Fig. 2 shows a cross-section of the tube of Fig.1 .

[0033] Fig. 3 shows a perspective view of the tube with circular micro-channels.

[0034] Fig. 4 shows a cross-section of the tube of Fig.3.

[0035] Fig. 5 shows a schematic view of the heat exchanger with the tubes.

[0036] DETAILED DESCRIPTION OF EMBODIMENTS

[0037] The subject-matter of the invention is, among others, a tube (1 ) for a high-pressure heat exchanger. It is thus self-explanatory that the tube (1 ) itself must also withstand high pressure. The tube 1 is configured to convey a first fluid. The highly pressurized first fluid may be any fluid, yet the tube is intended for use in a high- pressure refrigerant circuit, so the most suitable refrigerants are R744 (carbondioxide) and / or R290 (propane).

[0038] The tube (1 ) may comprise an axis of elongation (L1 ). The axis of elongation L1 is a reference point which helps to determine the longest direction, i.e. a length of the tube 1 . Although axis of elongation L1 is just conceptual, it may be used to measure the total length of the tube 1 , which can be measured in, for example millimeters, between the open ends of the tube 1 and in parallel to the axis of elongation L1 .

[0039] The tube 1 may further comprise a first main wall (4) and a second main wall (5) parallel to the first main wall (4). Each main wall (4, 5) may comprise substantially flat surface. In other words, the outer surfaces of the first main wall 4, the second main wall 5 or both may form respective planes, wherein the plane formed by the surface of the first main wall 4 may be parallel to the plane formed by the surface of the second main wall 5. Further, the tube 1 may comprise two complementary side walls (6) joining the main walls (4,5) together so as to define an outline of the tube (1 ). As shown in figures 1 -4, the outline of the tube may comprise two straight (flat) and parallel elements, and two rounded (arched) end portions connecting said parallel elements. The arched portions are juxtaposed with respect to each other so that they create a mirror image.

[0040] The tube (1 ) may comprise a width (W). The width (W) may be measured between the outermost portions of the side walls (6) and perpendicularly with respect to axis of elongation (L1 ).

[0041] The tube (1 ) may be internally divided into segments by at least one partition wall (100). The partition wall 100 may extend between the main walls (4, 5). Thanks to the partition wall 100, the tube 1 may comprise at least two micro-channels (101 ). The micro-channels (101 ) extend in parallel to the axis of elongation (L1 ) of the tube (1 ). In other words, the micro-channels 101 extending along the axis of elongation L1 of the tube 1 may form open ends thereof. It should be noted that the micro-channels (101 ) are configured to withstand burst pressure of at least 340 bar. The burst pressure is oftentimes a parameter required by customer, so that the tubes may be adapted to the parameters of the fluid circulating in the system. It is important that the burst pressure is as high as possible without exceeding weight and dimensional requirements. In other words it is important to provide a reasonably light tube according to customers packaging requirements which would withstand burst pressure of at least 340 bar.

[0042] In order to achieve this, the tube may be optimized by virtue of its parameters.

[0043] In order to provide lightweight and strength, a lightweight metallic material may be used for formation of the tube 1 . One of such metallic materials is aluminum.

[0044] From the construction point of view, the tube (1 ) may further comprise a height (H). The height (H) may be measured between the main walls (4, 5) of the tube (1 ). It is to say, the height (H) may be measured between the outermost flat surfaces of the first wall 4 and the second wall 5.

[0045] The tube may further comprised a nose width (A). Nose width (A) may be measured perpendicularly with respect to axis of elongation (L1 ), between the outermost portion of one of the side walls (6) and a portion of the neighboring micro-channel (101 ) which is located closest to said side wall (6). It should be noted that the nose width A is not measured on the partition walls 100, because these two are different sub-components of the tube 1. To put it simply, the nose width (A) could also be described as the “side wall thickness” or “side wall width”. Nose width (A) contributes to the mechanical strength against the debris, i.e. the resistance of the tube 1 to debris and particles which can fly into the tube 1 at high velocity.

[0046] The tube 1 may further comprise a main wall thickness (C). The main wall thickness may be measured as an average distance between the portions of the microchannels (101 ) located closest to the surface of the neighboring main wall (4,5) and the surface of said main wall (4, 5). The wall thickness C may be further measured in perpendicular with respect to the width (W) and longitudinal axis (L1 ) of the tube (1 ). It should be noted that the term “an average distance between the portions of the micro-channels (101 ) located closest to the surface of the neighboring main wall (4,5)” refers to a scenario in which the micro-channels 101 are of different shapes and / or sizes. In case all the micro-channels are identical and they are uniformly arranged, it is natural that the wall thickness (C) will be the distance between the portion of any micro-channel (101 ) located closest to the surface of the neighboring main wall (4,5) and the main wall 4, 5 itself. It is because the average distance of the portions of all micro-channels 101 would be the same as of the single one.

[0047] Further, the tube may comprise the partition wall (100) which comprises a partition width (B). The partition width may be measured in parallel with respect to the width (W) between the walls forming the neighboring micro-channels (101 ).

[0048] It should be noted that some parameters may implicate the orientation of the tube, for example width may implicate the horizontal direction of measurement, however, the orientation of the tube itself may vary, thus the reference points and dimensions described above shall be adapted to the orientation of the tube 1 .

[0049] In figures 1 and 2, the micro-channels (101 ) are in the shape of an oblong.

[0050] For this type of micro-channels, specific parameters may be introduced which allow the tube 1 to withstand the burst pressure of 340 bar and above. The height (H) of the tube may be between 1 ,21 mm and 1 ,45mm. In other words, 1 ,21 mm<H<1 ,45mm.

[0051] A ratio between the nose width (A) and the partition width (B) is between 0,78 and 2,9. In other words, 0,78<(A / B)<2.9.

[0052] A ratio between the partition width (B) and main wall thickness (C) may be between 1 ,2 and 2,9. In other words, 1 ,2<B / C<2,9.

[0053] In one variant, the tube (1 ) may comprise odd number of micro-channels (101 ). The odd number of channels allows allocating the partition wall centrally between the side walls 6 which may enhance the overall resistance of the tube 1 to the burst pressure of 340 bar and above.

[0054] In this context, the tube (1 ) may comprise not less than 11 micro-channels (101 ) and not more than 17 micro-channels (101 ).

[0055] Alternatively, the tube may comprise and even number of micro-channels 101 having an oblong shape. It should be noted that the oblong shape shall be regarded as two parallel lines connected by two juxtaposed semi- circular lines to form a closed profile. Oblong shape may also be called a “racetrack” shape or substantially oval shape.

[0056] In figures 3 and 4, the micro-channels (101 ) are of substantially rectangular shape.

[0057] As shown in Fig. 3 and Fig. 4, at least one micro-channel (101 ) located in the vicinity of side wall (6) comprises an arch-shaped portion (101 a). The arch-shaped portion (101 a) being arranged to imitate the outline of the side wall (6). The arch-shaped portion (101 a) allows increasing the capacity of the micro-channels 101 located in the vicinity of the side walls 4, 5.

[0058] Accordingly, the tube 1 having micro- channels 101 having substantially rectangular shape may comprise the parameters described below, in order to allow the tube to withstand the burst pressure of 340 bar and above.

[0059] The height (H) of the tube (1 ) may be between 1 ,20mm and 1 ,40mm. In other words, 1 ,2mm<H<1 ,4mm. A ratio between the nose width (A) and the partition width (B) may be between 3,0 and 6,7. In other words, 3,0<(A / B)<6,7.

[0060] A ratio between the partition width (B) and main wall thickness (C) is between 0,4 and 1 ,3. In other words, 0,4<(B / C)<1 ,3. Another object of the invention is a high- pressure heat exchanger (1000) comprising at least one tube (1 ) as described above. The high- pressure heat exchanger (1000) may further be called simply “heat exchanger”.

[0061] The heat exchanger (1000) further comprises a pair of manifolds (1001 , 1002) spaced apart from each-other. The manifolds (1001 , 1002) may comprise a plurality of slots to accommodate the tubes (1 ). The tubes (1 ) along with the manifolds (1001 , 1002) may be fluidly connected with each-other to provide a first fluid circuit.

[0062] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of drawings, the disclosure, and the appended claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to the advantage.

Claims

Claims1. A tube (1 ) for a high-pressure heat exchanger, the tube (1 ) comprising an axis of elongation (L1 ), a first main wall (4); a second main wall (5) parallel to the first main wall (4), each main wall (4, 5) comprising a substantially flat surface, and two complementary side walls (6) joining said main walls (4,5) together so as to define an outline of the tube (1 ), wherein the tube (1 ) comprises a with (W) measured between the outermost portions of the side walls (6) and perpendicularly with respect to axis of elongation (L1 ), wherein the tube (1 ) is divided into segments by at least one partition wall (100) extending between the main walls (4, 5) to form micro-channels (101 ), the micro-channels (101 ) extending in parallel to the axis of elongation (L1 ) of the tube (1 ), wherein the micro-channels (101 ) are configured to withstand burst pressure of at least 340 bar.

2. The tube (1 ) according to claim 1 , wherein said tube (1 ) further comprises a height (H), the height (H) being measured between the main walls (4, 5) of the tube (1 ), a nose width (A) measured perpendicularly with respect to axis of elongation (L1 ) between the outermost portion of one of the side walls (6) and a portion of the neighboring micro-channel (101 ) which is located closest to said side wall (6), a main wall thickness (C) measured as an average distance between the portions of the micro-channels (101 ) located closest to the surface of the neighboring main wall (4,5) and the surface of said main wall (4, 5), the wall thickness being measured in perpendicular with respect to the width (W) and longitudinal axis (L1 ) of the tube (1 ), and wherein the partition wall (100) further comprises partition width (B) measured in parallel with respect to the width (W) between the walls forming the neighboring micro-channels (101 ).

3. The tube (1 ) according to any of claims 1 or 2, wherein the micro-channels (101 ) are in the shape of an oblong.

4. The tube (1 ) according to claim 3, wherein the height (H) of the tube is between 1 ,21 mm and 1 ,45mm.

5. The tube (1 ) according to any of the claims 3 or 4, wherein a ratio between the nose width (A) and the partition width (B) is between 0,78 and 2,9.

6. The tube (1 ) according to any of the claims 3 to 5, wherein a ratio between the partition width (B) and main wall thickness (C) is between 1 ,2 and 2,9.

7. The tube (1 ) according to any of claims 3 to 6, wherein said tube (1 ) comprises odd number of micro-channels (101 ).

8. The tube (1 ) according to any of claims 3 to 7, wherein the tube (1 ) comprises not less than 1 1 micro-channels (101 ) and not more than 17 micro-channels (101 ).

9. The tube (1 ) according to any of claims 1 or 2, wherein the micro-channels (101 ) are of substantially rectangular shape.

10. The tube (1 ) according to claim 9, wherein at least one micro-channel (101 ) located in the vicinity of side wall (6) comprises an arch-shaped portion (101 a), the arch-shaped portion (101 a) being arranged to imitate the outline of the side wall (6).11 . The tube (1 ) according to any of claims 9 or 10, wherein the height (H) of the tube (1 ) is between 1 ,20mm and 1 ,40mm.

12. The tube (1 ) according to any of claims 9 to 11 , wherein a ratio between the nose width (A) and the partition width (B) is between 3,0 and 6,7.

13. The tube (1 ) according to any of the claims 3 to 5, wherein a ratio between the partition width (B) and main wall thickness (C) is between 0,4 and 1 ,3.

14. A heat exchanger (1000) comprising at least one tube (1 ) according to any of the preceding claims.

15. The heat exchanger (1000) according to claim 14, wherein the heat exchanger (1000) further comprises a pair of manifolds (1001 , 1002) spaced apart from each-other, the manifolds (1001 , 1002) comprising plurality of slots to accommodate the tubes (1 ), the tubes (1 ) along with the manifolds (1001 , 1002) being fluidly connected with each-other to provide a first fluid circuit.

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