Patent Application
20090242180
1. Field of the Invention
The subject invention is related to a tube assembly for a heat exchanger.
2. Description of the Prior Art
Various types of heat exchangers are used in automotive applications. It is known for a tube assembly in a heat exchanger to have a tube that defines a fluid passage and includes first and second sides spaced from and parallel to each other. Such tube assemblies can include a corrugated fin, having alternating ridges and grooves, that is disposed in the tube between the first and second sides, thereby subdividing the fluid passage into a plurality of passageways. Typically these assemblies are held together by braze disposed between the corrugated fin and the tube.
In recent years, the temperatures and pressures of air in heat exchangers has significantly increased, resulting in failure of heat exchangers. In such temperature/pressure conditions, a major disadvantage of prior art designs has been common failures, such as fatigue fracture, of both the tube and the corrugated fin. In prior art designs, specific fractures, such as transverse fractures, may occur, for example, at tube locations, and, in particular, at the inlet header of the heat exchangers. Also, corrugated fin fracture may occur and lead to contamination in heat exchangers.
In summary, the invention is a tube assembly for a heat exchanger and a method for manufacturing the tube assembly. The inventive tube assembly includes a tube defining a fluid passage. The tube has first and second sides spaced from and parallel to each other. The invention also includes a corrugated fin having alternating ridges and grooves and is disposed in the tube between the first and second sides, thereby subdividing the fluid passage into a plurality of passageways. At least one recess is defined in at least one of the ridges. The recess extends away from the closest one of the first and second sides towards an interior of the tube.
Advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, an exemplary tube assembly 20 is generally shown for use in a heat exchanger 22 in an automobile.
The exemplary heat exchanger 22 includes a first header 24. The first header 24 is typically aluminum, but may be any material known in the art. The first header 24 extends along a first centerline A and defines a plurality of first header tube slots 26 that are spaced along the first centerline A.
The exemplary heat exchanger 22 further includes a second header 28. The second header 28 is typically aluminum, but may be any material known in the art. The second header 28 is spaced from and parallel to the first header 24 and extends along a second centerline B. The second header 28 defines a plurality of second header tube slots 30 that are spaced along the second centerline B and aligned with the first header tube slots 26.
The exemplary heat exchanger 22 further includes a plurality of tube assemblies 20 and each tube assembly 20 includes a tube 32. The tubes 32 are typically aluminum, but may be any material known in the art. Each of the tubes 32 include a first side 34 and a parallel second side 36 that extend between semi-circular first and second edges 38, 40. Each of the tubes 32 extend from a first tube end 42 to a second tube end 44. The ends 42, 44 are received in the first and second header tube slots 26, 30 respectively. Each of the tubes 32 define a fluid passage 46 that extends from the first tube end 42 to the second tube end 44, establishing fluid communication between the first and second headers 24, 28.
The exemplary heat exchanger 22 further includes a plurality of air fins 48 for dissipating heat from the tubes 32. The air fins 48 are typically aluminum, but may be any material known in the art. Each of the air fins 48 are brazed between parallel first and second sides 34, 36 of adjacent tubes 32.
Each of the assemblies 20 further includes a corrugated fin 50. The corrugated fin 50 is typically aluminum, but may be any material known in the art. Each corrugated fin 50 has alternating ridges 52 and grooves 54, and is disposed in one of the tubes 32 between the first and second sides 34, 36. The inserted corrugated fin 50 subdivides the fluid passage 46 into a plurality of passageways 56. The ridges 52 are typically flat or rounded, but may be any configuration.
The assembly 20 includes at least one recess 58 being defined in at least one of the ridges 52. The recess 58 extends away from the closest one of the first and second sides 34, 36. The at least one recess 58 may be any shape known in the art including a rectangular or circular recess 58a, 58b. Further, the at least one recess 58c may extend along an entire length of the corrugated fin 50. Alternative embodiments of the invention can include a plurality of recesses 58, such as at least one recess 58 defined in a plurality of ridges 52 or a plurality of recesses 58 defined in a single ridge 52. A quantity of flux may be disposed only in the recesses 58, or may be disposed the entire length of the ridge 52.
As such, the corrugated fin 50 has the ability to retain and transport flux as it is inserted in the tube 32. The at least one recess 58 further allows for an even distribution of flux over the tube 32 length which allows for better bonding. With uniform distribution of flux over the tube 32 length, tube 32 failure due to high pressure excursions will be greatly reduced. The at least one recess 58 further allows for a reduced amount of flux to be used. With the at least one recess 58, there is no need to over flux the corrugated fin 50 to compensate for flux lost during the insertion of the corrugated fin 50 into the tube 32. Further, the reduction of flux and the use of at least one recess 58 allow for a reduction in the potential for flux contamination of downstream components due to the excessive application of flux on the corrugated fin 50.
While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
