U.S. patent application number 15/226990 was filed with the patent office on 2017-02-09 for brazed heat exchanger and production method.
The applicant listed for this patent is Modine Manufacturing Company. Invention is credited to Klaus Kalbacher, Andreas Koepke, Wolfgang Schatz-Knecht.
Application Number | 20170038150 15/226990 |
Document ID | / |
Family ID | 57782282 |
Filed Date | 2017-02-09 |
United States Patent
Application |
20170038150 |
Kind Code |
A1 |
Kalbacher; Klaus ; et
al. |
February 9, 2017 |
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.
Inventors: |
Kalbacher; Klaus;
(Rangendingen, DE) ; Koepke; Andreas;
(Filderstadt, DE) ; Schatz-Knecht; Wolfgang;
(Reutlingen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Modine Manufacturing Company |
Racine |
WI |
US |
|
|
Family ID: |
57782282 |
Appl. No.: |
15/226990 |
Filed: |
August 3, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28D 2021/0049 20130101;
F28F 9/0251 20130101; F28F 3/046 20130101; F28D 9/005 20130101;
F28F 2275/045 20130101; F28F 3/086 20130101; F28F 3/042 20130101;
F28D 2021/0089 20130101; F28F 21/089 20130101; B23K 1/0012
20130101 |
International
Class: |
F28D 9/00 20060101
F28D009/00; F28F 3/04 20060101 F28F003/04; F28F 9/007 20060101
F28F009/007; F28F 3/08 20060101 F28F003/08; F28F 21/08 20060101
F28F021/08 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 8, 2015 |
DE |
10 2015 010 310 |
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
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to German Patent
Application No. 10 2015 010310, filed Aug. 8, 2015, the entire
contents of which are hereby incorporated by reference herein.
BACKGROUND
[0002] The invention relates to a heat exchanger which is brazed in
a brazing furnace, comprising stacked heat exchanger parts which
provide first and second channels, and with brazing material, at
least arranged in brazed connection seams, the one brazing material
on surfaces in the first channels being different than the other
brazing material on other surfaces in the second channels. The
invention also relates to production methods for said heat
exchangers.
[0003] A heat exchanger of this type with a production method was
filed recently at the DPMA and received the reference number DE 10
2014 015 170.0.
[0004] The different brazing materials are preferably brazing
materials based on different substances, for example copper brazing
materials and iron brazing materials.
[0005] Certain alloy constituent parts, of which it is said that
they might trigger disadvantageous effects in connected circuits in
dissolved form, can be eliminated by way of the heat exchanger of
the earlier application, and costs can also possibly be
reduced.
[0006] In the meantime, the applicant has carried out practical
test series and has determined that there is further need for
improvement. This applies, for example, with regard to the higher
strength which is necessary for many applications of the heat
exchanger.
SUMMARY
[0007] It is the object of the invention to improve the heat
exchanger from the earlier application. Improved strength
properties are to be achieved by way of one particularly preferred
exemplary embodiment.
[0008] According to the invention, this object is achieved by way
of a heat exchanger which is brazed in a brazing furnace.
[0009] According to one important aspect of the invention, it is
provided that the one brazing material is preferably present at
least partially in an upper and/or lower channel of the first or
second channels of the heat exchanger which are assigned to the
first or the second medium, and that the other brazing material is
arranged in the remaining first or in the remaining second channels
for the same medium.
[0010] This does not necessarily have to be the uppermost or the
lowermost channel. In general, this means equipping one channel or
some channels on one medium side or even on both medium sides at
least partially with another brazing material than the other
remaining channels on the respective medium side, in order to
provide the heat exchanger with the advantages which are to be
assigned to said other brazing material.
[0011] With regard to strength, actually only the one uppermost
and/or the one lowermost channel are/is of significance in
practice, because the greatest loads will occur there and the
strength is therefore to be increased there. This can be the first
channel which lies below a cover plate or above a base plate and/or
can also be, for example, the second channel, namely depending on
the respective medium side which is to be reinforced.
[0012] It should be understood that the proposed embodiment of the
uppermost and/or the lowermost channels can also be present on both
medium sides of the heat exchanger, if a special application should
require an embodiment of this type.
[0013] An alternative solution according to the invention provides
that there is at least one first part region in all of the first
channels or in all of the second channels, in which part region the
one brazing material is arranged, and there is at least one second
part region, in which the other brazing material is arranged.
[0014] The invention proceeds, inter alia, from the knowledge that,
for example, a copper-based brazing material which contains almost
exclusively copper can provide a higher strength than, for example,
an iron-based brazing material which has different other alloy
constituent parts.
[0015] One result of the tests which were addressed in the
introductory part has proven to be that no damage caused by
dissolution of copper occurred in the connected circuits as a
result of the provision of copper brazing substance merely in the
upper and the lower channel, which are loaded the most with regard
to strength, of the first or the second channels. All of the
remaining first or the remaining second channels, which therefore
represent the majority of the channels, have namely been equipped
with an iron-based brazing material, as in the earlier application.
The overall quantity of, for example, copper therefore still
remains below a threshold which triggers supposed damage.
[0016] This also applies to aforementioned alternative solution
because the part regions which are provided with copper brazing
substance in the first or in the second channels are relatively
small.
[0017] In addition, one particularly preferred exemplary embodiment
of the heat exchanger arranges for not providing the uppermost
and/or the lowermost channel completely with copper brazing
substance, but rather only partially, as a result of which the
quantity of copper used is reduced further, but the strength can be
increased to a sufficient extent, in comparison with the earlier
application. The remaining brazing substance in the upper and/or in
the lower channels can be an iron-based brazing substance. In this
context, "partially" is therefore to be understood to mean that
there are areas in said channels which have the copper brazing
substance and other areas in the same channels which are provided
with the iron brazing substance.
[0018] In a heat exchanger according to an embodiment of the
invention, the heat exchanger parts of which, which form the
channels, are heat exchanger plates which are stacked inside one
another and have two inlets and two outlets, the addressed areas
with the copper brazing substance are mainly those which are
situated in a region around the inlets and outlets. In contrast,
the addressed other areas within the channels which are provided
with the iron brazing substance are those areas which are present
in a middle plate or channel region between the inlets and
outlets.
[0019] If the heat exchanger is an oil cooler which is cooled by
means of liquid, it is provided in one very particularly preferred
exemplary embodiment, in simple terms, to equip all of the channels
which are assigned to the oil with the copper brazing material. In
the liquid channels, in contrast, the uppermost and/or the
lowermost channel are/is provided (partially) with the copper
brazing material, whereas all the remaining channels for the liquid
are provided completely with the iron brazing material.
[0020] The brazed heat exchangers according to some embodiments of
the invention comprise, as a first type, what are known as
"caseless" heat exchangers, in which the heat exchanger parts are
usually configured as trough-shaped plates which are stacked inside
one another. Heat exchanger plates of this type have at least four
openings which, as has already been mentioned, form four inlet or
outlet channels which extend through the stack. One inlet channel
and one outlet channel are assigned to in each case one medium. In
said first heat exchanger type, all the channels are closed
channels. Closed channels are those which are closed all around by
means of connected plate edges.
[0021] The heat exchangers according to some embodiments of the
invention also include those of a second type which has a housing,
in which the stack is arranged. As heat exchanger parts, said stack
has tubes or else plate pairs and fins which form tubes or (as an
alternative) lobes, between the tubes or the plate pairs, with
closed channels in the tubes or plate pairs and with other, open
channels, in which the fins or the lobes are arranged. If the heat
exchanger parts are single-piece tubes, in particular flat tubes,
they are closed at their opposite ends by way of crimping or
folding, as known in the art.
[0022] Open channels are those which are at least partially open on
the circumferential side, but are preferably completely open all
the way around.
[0023] Said heat exchanger parts as a rule have merely two openings
in the plates or in the flat tube walls, which openings form an
inlet channel and an outlet channel in the plate stack for the
medium which flows through the closed channels. The second medium
flows into the housing and subsequently flows through the other
channels which are open at least partially all around with the fins
or the lobes between the plate pairs, in order to subsequently
leave the housing.
[0024] Accordingly, the second heat exchanger type is distinguished
by way of an alternation in the stack of closed channels with the
open channels.
[0025] A suitable copper-based brazing material has a copper
proportion of approximately 99% copper or even more.
[0026] A suitable iron-based brazing material contains, for
example, 20% by weight chromium, 39% by weight iron and 20% by
weight nickel and also 10% by weight copper and other alloy
constituent parts in a relatively small quantity.
[0027] Another suitable iron-based brazing substance has 54% by
weight iron and merely 15% by weight chromium and 10% by weight
nickel and other alloy constituent parts, inter alia also 5% by
weight copper.
[0028] Copper-based and iron-based brazing materials have been
addressed up to now. This proposal is not to be restricted thereto,
however. Rather, combinations of other known brazing materials or
brazing alloys are to be included, it being possible for advantages
which are to be attributed to said brazing material alloys to be
achieved, for example an improvement with regard to resistance
against corrosion, but also further cost reductions, etc. The
different brazing materials should lie at least close to one
another or be approximately identical with regard to their melting
points, as has already been stated in the earlier application.
[0029] A heat exchanger according to the invention can also have
more than two different brazing materials.
[0030] The first and the second medium can be different media or
identical media (for example, two oils), but at different
temperatures.
[0031] The following description of exemplary embodiments is
particularly directed to those which have copper and iron brazing
materials, in order to improve the strength of the heat
exchanger.
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.
* * * * *