Brazed Heat Exchanger and Production Method

Abstract

The invention relates to a heat exchanger which is brazed in a brazing furnace, comprising stacked heat exchanger parts which provide first channels and second channels, and with at least two brazing materials, the one brazing material in the first channels being different than the other brazing material in the second channels. According to one alternative, said heat exchanger is improved by virtue of the fact that there is the other or the one brazing material in one or in a few of the first channels or the second channels or in one or in a few of the first and the second channels, or the other and the one brazing material are present arranged in part regions.

Claims

1. A brazed heat exchanger, comprising: a plurality of stacked plates defining a plurality of first channels for a first liquid and a plurality of second channels for a second liquid alternating in a plate stack direction; a first brazing material providing brazed connection seams in each one of the plurality of first channels; and a second brazing material different from the first brazing material providing brazed connection seams in at least some of the plurality of second channels, wherein at least one of the plurality of second channels has brazed connection seams provided by the first brazing material.

2. The brazed heat exchanger of claim 1, wherein said at least one of the plurality of second channels additionally has brazed connection seams provided by the second brazing material.

3. The brazed heat exchanger of claim 2, wherein said at least one of the plurality of second channels includes an inlet region for at least one of the fluids arranged at one end thereof, an outlet region for at least one of the fluids arranged at an opposing end thereof, and a central region between the inlet region and the outlet region, wherein brazed connection seams in the inlet and outlet regions are provided by the first brazing material and brazed connection seams in the central region are provided by the second brazing material.

4. The brazed heat exchanger of claim 1, wherein the second brazing material provides brazed connection seams in each one of the plurality of second channels.

5. The brazed heat exchanger of claim 1, wherein said at least one of the plurality of second channels includes an uppermost or a lowermost one of the plurality of second channels in the plate stack direction.

6. The brazed heat exchanger of claim 1, wherein said at least one of the plurality of second channels includes both an uppermost and a lowermost one of the plurality of second channels in the plate stack direction.

7. The brazed heat exchanger of claim 1, wherein the brazed connection seams in at least all of the plurality of second channels other than the uppermost two second channels and the lowermost two second channels are provided exclusively by the second brazing material.

8. The brazed heat exchanger of claim 7, wherein the brazed connection seams in at least all of the plurality of second channels other than the uppermost second channel and the lowermost second channel are provided exclusively by the second brazing material.

9. The brazed heat exchanger of claim 1, further comprising: a first and a second corrugated channel plate arranged within one of the at least one of the plurality of second channels that has brazed connection seams provided by the first brazing material; and a corrugated slat arranged within said channel between the first and second corrugated channel plates.

10. The brazed heat exchanger of claim 9, wherein the first and second corrugated channel plates are joined to those ones of the plurality of stacked plates defining said channel by brazed connection seams provided by the first brazing material, and wherein the corrugated slat is joined to those ones of the plurality of stacked plates defining said channel by brazed connection seams provided by the second brazing material.

11. The brazed heat exchanger of claim 1, wherein the first brazing material is a copper brazing material and wherein the second brazing material is an iron brazing material.

12. A brazed heat exchanger, comprising: a first plate; a second plate joined to the first plate by connected plate edges to form a first closed channel; a first part region of the first closed channel in which a first brazing material is arranged and a second part region of the first closed channel in which a second brazing material different from the first brazing material is arranged; a third plate joined to the second plate by connected plate edges to form a second closed channel, wherein the first brazing material but not the second brazing material is arranged in the second close channel; and a fourth plate joined to the third plate by connected plate edges to form a third closed channel, wherein the second brazing material but not the first brazing material is arranged in the second closed channel.

13. The brazed heat exchanger of claim 12, further comprising: a first inlet channel and a first outlet channel extending through the first, second, third, and fourth plates, wherein a cooling liquid is fed to the first and the third closed channels by the first inlet channel; and a second inlet channel and a second outlet channel extending through the first, second, third, and fourth plates, wherein an oil is fed to the second closed channel by the second inlet channel.

14. The brazed heat exchanger of claim 13, wherein the first and second inlet and outlet channels are arranged within the first part region of the first closed channel.

15. The brazed heat exchanger of claim 12, wherein the second part region of the first closed channel is a middle region of the first flow channel.

16. The brazed heat exchanger of claim 12, wherein the second, third, and fourth plates are trough-shaped plates that are stacked inside one another and wherein the first plate is a base plate or a cover plate.

17. A method of producing a brazed heat exchanger, comprising: assembling a plurality of heat exchanger parts into a stack to provide a set of first flow channels and a set of second flow channels in alternating sequence through the stack; arranging a plurality of first corrugated slats within the set of first flow channels; providing a first brazing material between peaks and troughs of the plurality of first corrugated slats and surfaces of the heat exchanger parts; arranging a plurality of second corrugated slats within the set of second flow channels; providing a second brazing material different from the first brazing material between peaks and troughs of the plurality of second corrugated slats and surfaces of the heat exchanger parts; arranging a plurality of corrugated plates within the set of second flow channels; providing a brazing material between surfaces of the plurality of corrugated plates and surfaces of the heat exchanger parts, wherein that brazing material is the first brazing material in one or more of the second flow channels; and heating the stack to a temperature sufficient to melt both the first and the second brazing materials.

18. The method of claim 17, wherein the first brazing material is a copper brazing material and wherein the second brazing material is an iron brazing material.

19. The method of claim 17, wherein the plurality of corrugated plates are arranged in inlet and outlet regions of the set of second flow channels.

20. The method of claim 17, further comprising: assembling a base plate at one end of the stack of heat exchanger parts; and assembling a cover plate at another end of the stack of heat exchanger parts opposite the one end, wherein one of the one or more second flow channels having the first brazing material between surfaces of the plurality of corrugated plates and surfaces of the heat exchanger parts is the second flow channel nearest either the base plate or the cover plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIGS. 1 to 3 show one exemplary embodiment using a caseless heat exchanger which has exclusively closed channels.

[0033] FIG. 4 shows one exemplary embodiment using a heat exchanger in a housing which has closed and open channels.

DETAILED DESCRIPTION

[0034] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the accompanying drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of including, comprising, or having and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms mounted, connected, supported, and coupled and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, connected and coupled are not restricted to physical or mechanical connections or couplings.

[0035] The basic material of those parts of the heat exchangers which are shown in the exemplary embodiments is a stainless steel. In other exemplary embodiments which are not shown, it can be, for example, an aluminum alloy or another metal which can be brazed with correspondingly different brazing materials.

[0036] FIG. 1 shows a view into an uppermost channel 2a which is preferably a cooling liquid channel. A heat exchanger part 1, in particular a heat exchanger plate 1 with an obliquely raised edge 10a can be seen. The edges 10a of the plates 1 are connected in order to form the closed channels. Four holes are situated in said heat exchanger plates 1. A further heat exchanger plate 1 is laid on top in order to form the liquid channel which is shown. Said further heat exchanger plate (not shown) might also be a cover plate which normally has somewhat thicker walls than a heat exchanger plate 1. The upper left-hand and the upper right-hand hole is a part of an inlet channel and an outlet channel 14, 15, respectively. By means of said inlet and outlet channel 14, 15, the channel 2b (not shown) which is adjacent toward the bottom, preferably an oil channel, is fed. The channels 2a and 2b alternate in the vertical plate stack direction, as is usually customary at any rate. The inlet and outlet channels 12, 13, 14, 15 which are formed in this way are otherwise clearly visible in FIG. 2 which shows a perspective view of the plate stack. The lower right-hand and the lower left-hand hole and the inlet and outlet channels 12, 13 which are formed from them in the plate stack are correspondingly provided for the cooling liquid. It can accordingly be assumed that the cooling liquid flows into the cooling liquid channel 2a which is shown at the bottom right and leaves said channel 2a again at the bottom left (FIG. 1).

[0037] Furthermore, as is apparent from FIGS. 1 and 2, in each case one corrugated channel plate 4a is situated in the upper liquid channel which is shown and preferably also in all other liquid channels of the heat exchanger, on the left and right in the inlet region and in the outlet region of the liquid channel. The corrugated channel plates 4a have in each case two openings which correspond in each case with one of the abovementioned holes in the plates 1. The openings are therefore slightly larger than the holes. Furthermore, the channel plates 4a usually have arcuate corrugations which firstly lead from the inlet channel to a middle plate region and secondly lead from the middle plate region to the outlet channel. To this end, in each case apertures are arranged in the channel plates 4a at the ends of the corrugations. Where the corrugations are formed, the liquid can flow between the channel plate 4a and the lower heat exchanger plate 1. Where the channel plates 4a are configured without corrugations, that is to say are of planar configuration, the liquid flows between the channel plate 4a and the upper heat exchanger plate 1. In order to further improve the stability, individual lobes 11 are also present in the corrugated channel plates 4a.

[0038] In the abovementioned middle plate or channel region, a corrugated slat 4b is situated between the two channel plates 4a, the details of which corrugated slat 4b are shown in FIG. 3. As is known, the corrugations of the channel plates 4a and the slats 4b have corresponding corrugation peaks 4bg and corrugation troughs 4t. The slat 4b has cuts in the corrugation flanks 42.

[0039] All the liquid channels can be of identical configuration with regard to the above-described embodiment.

[0040] The following is provided with regard to the brazing materials which are present in FIGS. 1, 2 and 3: a copper brazing material 3b, indicated in FIG. 1 merely by way of some thick, arcuate lines which lie on the corrugation peaks 4bg, is situated on the visible upper side on the corrugations of the channel plates 4a. By way of this, the brazed connection is produced with the plate 1 (not shown) which lies on the channel 2a. The copper brazing material 3b for connecting to a bottom of the heat exchanger plate 1 which is shown is also situated on the non-visible underside of the channel plates 4a. The copper brazing material 3b on the underside has to be situated on the planar areas which lie on the bottom of the heat exchanger plate 1 and which can also be understood to be corrugation troughs 4t.

[0041] In contrast, an iron brazing material 3a, indicated merely by way of a single oval in FIG. 1 and by way of some lines in FIG. 3, is situated on the upper side and on the underside of the slat 4b and on its corrugation peaks 4bg and corrugation troughs 4t. Said embodiment applies to the upper channel 2a which is shown and to the lower channel 2a which is not shown.

[0042] In contrast, exclusively the iron brazing material 3a is situated in all remaining channels 2a which are assigned to the cooling liquid.

[0043] In one exemplary embodiment which is not shown, not only is the uppermost channel 2a configured as described with regard to the brazing materials 3a, 3b, but rather also the following liquid channel 2a.

[0044] FIGS. 1 to 3 have not shown the oil channels in detail. The oil channels might be provided completely with a slat 4b (shown in FIG. 3) or might also be of some other configuration. Exclusively the copper brazing material 3b is situated therein in said exemplary embodiment, in order to withstand the high pressure on the oil side.

[0045] In FIG. 1, two first part regions A have also been marked which are arranged to the left and the right of a second part region B which corresponds to the abovementioned middle plate or channel region. The part regions A correspond to the likewise abovementioned inlet and outlet regions. In contrast to the above-described embodiment, according to which merely the upper or else also the next following liquid channel is configured with both brazing materials 3a, 3b, all the liquid channels of the heat exchanger are configured with the one and with the other brazing material 3a, 3b in the alternative embodiment. The copper brazing material 3b is therefore situated in the two part regions A and the iron brazing material 3a is situated in the second part region B. Exclusively the copper brazing material 3b is also situated in all the oil channels here.

[0046] FIG. 4 shows the oil channels there in somewhat greater detail. They are situated within tubes which are formed in this exemplary embodiment from pairs of plates 1 which are connected at their plate edges 10b and which therefore produce in each case one closed channel (first channel 2a). In contrast to the first exemplary embodiment, said plates 1 have merely two openings. In each case one open channel (second channel 2b) is situated between the tubes. The housing G which is present in said exemplary embodiment and in which the stack according to FIG. 4 is situated has been indicated in a similar manner to a frame. The open channels are flowed through by a cooling liquid which enters into the housing G and leaves the housing G again after having flowed through the open channels. The cooling liquid has been symbolized by way of block arrows and the oil by way of dashed arrows in FIG. 4.

[0047] Exclusively a copper brazing material 3b is also situated within the oil channels in said exemplary embodiment.

[0048] In each case two other channel plates 4c are situated in the open channels. In contrast to the first exemplary embodiment, the said other channel plates 4c have merely a single opening. They are also of corrugated configuration, however, in order that they can be flowed through just like the channel plates 4a of the first exemplary embodiment. The opening corresponds with one of the abovementioned two plate openings. A copper brazing material 3b is situated in the upper, open channel which is shown, whereas an iron brazing material 3a is situated in the remaining other open channels which are not shown in detail. In FIG. 4, the copper brazing material 3b has been shown as a brazing film, without being restricted hereto. It might also be, for example, a brazing paste or a brazing coating. The brazing film has been provided with cutouts, in order that the brazing material 3b is present only where it is required, for example in order to connect two lobes 11 which lie opposite one another and are configured in the plates 1, and which in each case protrude into the open channels.

[0049] Various alternatives to the certain features and elements of the present invention are described with reference to specific embodiments of the present invention. With the exception of features, elements, and manners of operation that are mutually exclusive of or are inconsistent with each embodiment described above, it should be noted that the alternative features, elements, and manners of operation described with reference to one particular embodiment are applicable to the other embodiments.

[0050] The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention.