HEAT EXCHANGER

Abstract

A heat exchanger (1) includes a first manifold (2) and a second manifold (3) fluidically connected by at least one tube (4) with at least one brazed joint between one manifold (2,3) and the tube (4). The brazed joint is made of braze material. The first manifold (2) and the second manifold (3) are formed from non-braze materials with a higher melting point than the braze material. The non-braze material does not melt during brazing. At least one of the manifolds (2,3) has at least two non-braze material layers.

Claims

1. A heat exchanger (1) comprising: a first manifold (2); a second manifold (3); at least one tube (4) with a tube profile (5) fluidically connecting the first manifold and the second manifold, the tube profile (5) having at least one channel (6) for a flow of a fluid between the first manifold (2) and the second manifold (3); and at least one brazed joint between one of the first and second manifolds (2,3) and the tube (4), the brazed joint being made of braze material; wherein the first manifold (2) and the second manifold (3) are formed from non-braze materials with a higher melting point than the braze material, the non-braze material being configured not to melt during brazing; and wherein at least one of the first and second manifolds (2,3) has at least two non-braze material layers.

2. The heat exchanger according to claim 1, wherein the at least one of the first and second manifolds (2,3) with the at least two non-braze material layers has an inner non-braze material layer (7) and an outer non-braze material layer (8), where the outer non-braze material layer (8) is more anodic than the inner non-braze material layer (7).

3. The heat exchanger according to claim 2, wherein the at least one of the first and second manifolds (2,3) with the at least two non-braze material layers is formed by roll forming and welding.

4. The heat exchanger according to claim 2, wherein the at least one of the first and second manifolds (2,3) with the at least two non-braze material layers is formed by coextrusion.

5. The heat exchanger according to claim 2, wherein the at least one of the first and second manifolds (2,3) with the at least two non-braze material layers is formed by coextrusion followed by drawing.

6. The heat exchanger according to claim 1, wherein the at least one of the first and second manifolds (2,3) with the at least two non-braze material layers has an inner non-braze material layer (7) and an outer non-braze material layer (8), where the outer non-braze material layer (8) has an equal or higher strength than the inner non-braze material layer (7).

7. The heat exchanger according to claim 6, wherein the at least one of the first and second manifolds (2,3) with the at least two non-braze material layers is formed by roll forming and welding.

8. The heat exchanger according to claim 6, wherein the at least one of the first and second manifolds (2,3) with the at least two non-braze material layers is formed by coextrusion.

9. The heat exchanger according to claim 6, wherein the at least one of the first and second manifolds (2,3) with the at least two non-braze material layers is formed by coextrusion followed by drawing.

10. A heat exchanger (1) comprising: a first manifold (2); a second manifold (3); at least one tube (4) with a tube profile (5) fluidically connecting the first manifold and the second manifold, the tube profile (5) having at least one channel (6) for a flow of a fluid between the first manifold (2) and the second manifold (3); and at least one brazed joint between one of the first and second manifolds (2,3) and the tube (4), the brazed joint being made of braze material; wherein the first manifold (2) and the second manifold (3) are formed from non-braze materials with a higher melting point than the braze material, the non-braze material being configured not to melt during brazing; and wherein at least one of the first and second manifolds (2,3) is formed from a single strip of a non-braze material by roll forming and welding.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the drawings,

[0028] FIG. 1 shows a heat exchanger according to the invention,

[0029] FIG. 2 shows a cross-section of a manifold with two non-braze material layers according to the invention,

[0030] FIG. 3 shows a cross-section of a folded tube before brazing according to the invention.

[0031] The drawings are schematic representations that are not necessarily drawn to scale, unless expressly mentioned. The drawings are included for illustrative purposes only and are not intended to limit the scope of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0032] According to FIG. 1, a heat exchanger 1 according to the invention has a first manifold 2 and a second manifold 3 being spaced apart and fluidically connected by at least one tube 4. The heat exchanger 1 comprises a plurality of tubes 4 which are spaced apart. Adjacent tubes 4 are respectively interconnected by a fin arrangement 9 with a corrugated fin in order to increase the available surface area for heat transfer.

[0033] The heat exchanger 1 may be fluidically connected to fluid circuit of a vehicle which is not shown in the figures. This fluid circuit may have least one electrically driven conveying unit for driving a first fluid within the fluid circuit. The fluid circuit may be a part of an HVAC (Heating, Ventilation and Air Conditioning) system of a vehicle.

[0034] The first manifold 2 has an inlet 10 and the second manifold 3 has an outlet 11. The first fluid may flow through the inlet 10 into the heat exchanger 1 and may leave the heat exchanger 1 through the outlet 11.

[0035] The first fluid flowing from the first manifold 2 to the second manifold 3 through the tubes 4 is in thermal contact with interior surfaces of the tubes 4, while a second fluid, such as ambient air, is in thermal contact with exterior surfaces of the tubes 4. Additionally, the second fluid is in contact with the fin arrangements 9. As long as the two fluids have different temperatures, a heat transfer from the warmer to the colder fluid can be achieved through the tubes 4 and fin arrangements 9.

[0036] The first manifold 2, the second manifold 3 and the tube 4 are assembled such that the first manifold 2 and the second manifold 3 are fluidically connected by the tube 4. This assembly is brazed or furnace brazed in order to create brazed joints between the manifolds 2,3 and the tube 4. This provides a cost-efficient and modular production of the heat exchanger.

[0037] FIG. 2 shows a cross-section of a manifold 2 with two non-braze material layers according to the invention. The manifold 2 has a tube-like cross-section with an inner non-braze material layer 7 and an outer non-braze material layer 8. The outer non-braze material layer 8 may have a higher strength than the inner non-braze material layer 7. Additionally, the outer non-braze material layer 8 may be more anodic than the inner non-braze material layer 7. For a certain period of time, corrosion will only affect the outer non-braze layer 8. Thus, the corrosion resistance and the structural strength of the manifold 2 may be improved. The manifold 2 may comprise several non-braze material layers with different material properties in order to meet technical requirements. The manifold 2 shown in FIG. 2 may be manufactured by roll forming or coextrusion.

[0038] FIG. 3 shows a cross-section of a tube 4 before brazing according to the invention. In this case, the tube 4 is a folded tube 4a. The folded tube 4a comprises a tube profile 5 and braze material 12. The first manifold 2, the second manifold 3 and the tube profile 5 are formed from non-braze materials with a higher melting point than the braze material 12.

[0039] The tube profile 5 is formed from a strip of heat conductive material by roll forming. The heat conductive material is shaped in such a way that the tube profile 5 provides two channels 6 for a flow of the first fluid between the first manifold 2 and the second manifold 3. Due to the folding of the heat conductive material, at least one gap 13 extending in a longitudinal direction of the tube profile 5 is created. This gap 13 may have a triangular-shaped or delta-shaped cross-section. The braze material 12 may extend substantially along the length of the folded tube 4a and may enclose the tube profile 5. During a brazing process, the braze material 12 of the respective folded tube 4a melts and creates a longitudinal seam closing the gap 13 of the respective folded tube 4a. Additionally, the braze material 12 creates brazed joints between the first manifold 2 and the second manifold 3 and the respective folded tube 4. Since the liquid braze material fills the gap 13 evenly, a flow of the liquid braze material along the gap 13 in longitudinal direction of the tube profile 5 is avoided. Due to this, an erosion of the respective folded tube 4a is supressed.

[0040] While the above description constitutes the preferred embodiments of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.