Patent Application
20150159963
This nonprovisional application claims priority to German Patent Application No. DE 10 2013 225 326.5, which was filed in Germany on Dec. 9, 2013, and which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to a heat exchanger.
2. Description of the Background Art
DE 10 2005 031 475 A1 discloses a heat exchanger which has a tube-fin block closed on both sides by a collecting box. For receiving a coolant each collecting box has two side walls, two end walls, a cover, and a bottom arranged opposite to the cover. The bottom thereby comprises one or more openings for receiving tubes of the tube-fin block. The cover has a recess into which a partition wall extends dividing the interior space of the collecting tank into two subchambers.
In the conventional are, if one of two subchambers is formed as a high-temperature chamber and the other of the two chambers as a low-temperature chamber, high stresses occur that extremely strain the heat exchanger in the area of the partition wall. If a coolant flows through the high-temperature chamber, thermal stresses are created in the tubes. The thus arising forces from the high-temperature chamber are the cause for a bottom-surface shifting relative to the low-temperature chamber to occur. The shifting causes an expansion of the tubes at the bottom connection. As a result, defects can arise in the area of the partition walls, which occur, for example, as cracks in the tubes.
To prevent such disadvantageous defects, DE 10 2007 044 742 A1 discloses a heat exchanger in which the two chambers are separated not only spatially but are configured having a distance from one another.
However, conventional heat exchangers comprise a more complex structure increasing the assembly effort and thereby the production costs of the heat exchanger. Moreover, this type of design does not guarantee the complete prevention of damage to the tubes. The heat exchangers do not allow a sufficient temperature expansion compensation, because the cover of the heat exchanger is made of a continuous sheet profile.
It is therefore an object of the present invention to provide a heat exchanger in which the stresses in the transitional region between the high-temperature chamber and low-temperature chamber are relieved, without substantially increasing the costs for the production of the heat exchanger.
An exemplary embodiment relates to a heat exchanger, in which a first stress decoupling device is formed in the bottom and/or a second stress decoupling device in the area of the partition wall in the cover of at least one collecting tank. With the aid of such stress decoupling devices, stresses arising during the flow of a coolant from the high-temperature chamber into the low-temperature chamber can be prevented in a simple manner even if the high-temperature chamber is arranged not spaced apart but directly next to the low-temperature chamber. Tube expansions subjected to uncontrolled thermal loads are thereby compensated, because the stress decoupling device enables a shifting between the bottom and cover to one another. The formation of a stress decoupling device requires only little effort, which reduces the heat exchanger production costs.
According to an embodiment of the invention, in the case of the first stress decoupling device of the bottom, a slot, which is expanded by a further slot in the transverse direction of the bottom, runs in the longitudinal direction of the bottom. A controlled attenuation of the stiffness between the cover and bottom in the area of the partition wall occurs via such a stress decoupling device. The stresses applied to the tubes are reduced by this increased mobility of the bottom. Despite such stress decoupling devices, the heat exchanger always still has a sufficient pressure resistance, so that no medium flowing in the heat exchanger can leak outside.
In an embodiment, the cover can be connected to the bottom by a flange, particularly by a corrugated slot flange. The different material stresses on the tubes can be easily relieved by the open first stress decoupling device of the bottom in the area of the partition wall. The stress reduction occurs by the now possible step offset of the base plane of the bottom between the high-temperature chamber and the low-temperature chamber.
In an embodiment, the second stress decoupling device can have a corrugated configuration in the cover. Thus, the cover can create a step offset between the high-temperature and the low-temperature chamber. In addition to the variable offset of the base plane, the cover can follow this compensatory movement of the bottom.
In an embodiment, the corrugation can be formed V- or U-shaped. As a result, the load due to higher stresses on the tubes is minimized. A further structural modification of the cover for stress decoupling can be omitted.
In an embodiment, the cover can be lowered in the area of the partition wall in the direction of the bottom, whereby the partition wall is formed between the corrugation and the circumferential border forming the base of the cover. This assures that the high-temperature chamber and the low-temperature chamber are securely delimited from one another.
Advantageously, the height of the partition wall resting on the bottom can correspond to≦50% of the total height of the cover. As a result, sufficient movement of the cover in the case of the introduced corrugation in regard to the stresses arising between the high-temperature chamber and low-temperature chamber is assured, as a result of which the cover can follow the movement of the bottom.
In an embodiment, the height of the partition wall can correspond to 1 to 100% of the height of the circumferential sheathing of the cover. As a result, reliable closing devices, which are provided for connecting a corrugated slot flange of the sheathing of the cover with the bottom, can be used without modification. Moreover, a lower force application is necessary in connecting the cover with the bottom.
In a further embodiment, a seal, particularly a sealing frame, can be arranged between the partition wall and the bottom.
In an embodiment, the first stress decoupling device of the bottom can be formed as an attenuation elasticity. Such attenuation elasticities assure that the bottom itself can react to the acting stresses and can contribute to a compensation, whereby the stiffness of the bottom at the tubes engaging in the bottom is reduced.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:
A plan view of cover 13 of collecting tank 3 is shown in
As is shown in
A section of
Corrugation 11 of cover 13 has a similar effect, as is evident from
It is conceivable that in addition to corrugation 11 of cover 13 and slots 20 of bottom 14, bottom attenuations (not shown further) are introduced also as a mirror image to partition wall 12 or asymmetrically to partition wall 12 in bottom 14; these allow additional elasticity for bottom 14 to compensate such shifts of bottom 14.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 225 326.5 | Dec 2013 | DE | national |
