U.S. patent application number 09/796554 was filed with the patent office on 2001-09-06 for heat exchanger and heating or air conditioning unit of a motor vehicle containing said heat exchanger.
This patent application is currently assigned to BEHR GmbH & Co.. Invention is credited to Klingler, Dietrich, Voigt, Klaus.
Application Number | 20010018968 09/796554 |
Document ID | / |
Family ID | 7633300 |
Filed Date | 2001-09-06 |
United States Patent
Application |
20010018968 |
Kind Code |
A1 |
Klingler, Dietrich ; et
al. |
September 6, 2001 |
Heat exchanger and heating or air conditioning unit of a motor
vehicle containing said heat exchanger
Abstract
The invention relates to a heat exchanger of a plate-type
construction having first flow channels for a first heat exchange
medium, each formed by a pair of plates, and having corrugated
fins, around which a second heat exchange medium flows, arranged
between neighboring plate pairs. In order to provide an improved
heat exchanger which allows a more compact construction when used
in a heating or air conditioning unit of a motor vehicle, it is
proposed that the corrugated fins and at least one of the
neighboring plate pairs form second flow channels for the second
heat exchange medium and the second flow channels have a curved
course, so that the second heat exchange medium undergoes a change
of flow direction on flowing through the heat exchanger.
Inventors: |
Klingler, Dietrich;
(Heubach, DE) ; Voigt, Klaus;
(Bietigheim-Bissingen, DE) |
Correspondence
Address: |
Richard L. Schwaab
FOLEY & LARDNER
Washington Harbour
3000 K Street, N.W., Suite 500
Washington
DC
20007-5109
US
|
Assignee: |
BEHR GmbH & Co.
|
Family ID: |
7633300 |
Appl. No.: |
09/796554 |
Filed: |
March 2, 2001 |
Current U.S.
Class: |
165/140 ;
165/167 |
Current CPC
Class: |
F28D 2021/0085 20130101;
B60H 1/00328 20130101; F28F 3/025 20130101; F28D 1/0426 20130101;
B60H 2001/00078 20130101; F28D 1/0341 20130101; F28D 1/0461
20130101; F28F 2009/0287 20130101; F28F 3/04 20130101; F28D
2021/0096 20130101 |
Class at
Publication: |
165/140 ;
165/167 |
International
Class: |
F28D 007/10; F28F
003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 2, 2000 |
DE |
100 10 266.2 |
Claims
We claim:
1. A plate-type heat exchanger comprising: a plurality of stacked
plates, with respective adjacent plates forming pairs of plates,
the plates of the pairs being joined together to define a plurality
of first flow channels therebetween for carrying a first heat
exchange medium; and fins arranged between neighboring pairs of
said plates, said fins and at least one of said neighboring pairs
of plates forming a plurality of second flow channels for carrying
a second heat exchange medium; wherein said fins are shaped such
that the second heat exchange medium has a general flow direction
in said second flow channels that is changed as it flows through
the heat exchanger.
2. A heat exchanger according to claim 1, wherein said fins
comprise corrugated fins.
3. A heat exchanger according to claim 2, wherein said second flow
channels have a curved course for heat exchange medium flow.
4. A heat exchanger according to claim 3, further comprising: an
inflow face for said second heat exchange medium; and an exit face
for said second heat exchange medium, wherein said inflow face and
said exit face are arranged at an angle to one another.
5. A heat exchanger according to claim 3, wherein said second heat
exchange medium comprises air.
6. A heat exchanger according to claim 5, further comprising: an
inflow face for said second heat exchange medium; and an exit face
for said second heat exchange medium, wherein said inflow face and
said exit face are arranged at an angle to one another.
7. A heat exchanger of claim 3, wherein at least two of said second
flow channels have different lengths.
8. A heat exchanger of claim 7, wherein said second flow channels
include flow channels of shorter length and flow channels of longer
length, and wherein the shorter second flow channels are located in
an area of the heat exchanger in which the first heat exchange
medium is at a warmer temperature than its temperature when in the
area of the heat exchanger where the longer second flow channels
are located.
9. A heat exchanger of claim 7, further comprising: at least one
passage aperture for the first heat exchange medium, wherein each
of said second flow channels is of increasing length with
increasing distance from said passage aperture.
10. A heat exchanger of claim 4, wherein said second flow channels
have an arcuate course for heat exchange medium flow.
11. A heat exchanger of claim 9, wherein said second flow channels
have an arcuate course for heat exchange medium flow.
12. A heat exchanger of claim 10, wherein said second flow channels
have a circular arcuate course for heat exchange medium flow.
13. A heat exchanger of claim 11, wherein said second flow channels
have a circular arcuate course for heat exchange medium flow.
14. A heat exchanger of claim 3, wherein said first flow channels
have a serpentine course for heat exchange medium flow.
15. A heat exchanger of claim 9, wherein said first flow channels
have a serpentine course for heat exchange medium flow.
16. A heat exchanger of claim 3, wherein said fins are formed by
punching sheet metal.
17. A heat exchanger of claim 9, wherein said fins are formed by
punching sheet metal.
18. A heat exchanger of claim 1, wherein at least two of said
second flow channels have different lengths.
19. A heat exchanger of claim 18, wherein said plates are shaped as
a radial sector of a circle and wherein said plurality of second
flow channels have circular arcuate flow paths of different
lengths.
20. A heat exchanger of claim 19, further comprising: at least one
passage aperture for the first heat exchange medium located in said
plates in an inner radial location, wherein each of said second
flow channels is of increasing length with increasing distance from
said passage aperture.
21. A heat exchanger system comprising: a first plate-type heat
exchanger, said first plate-type heat exchanger comprising: a
plurality of stacked plates, with respective adjacent plates
forming pairs of plates, the plates of the pairs being joined
together to define a plurality of first flow channels therebetween
for carrying a first heat exchange medium; and fins arranged
between neighboring pairs of said plates, said fins and at least
one of said neighboring pairs of plates forming a plurality of
second flow channels for carrying a second heat exchange medium;
wherein said fins are shaped such that the second heat exchange
medium has a general flow direction in said second flow channels
that is changed as it flows through the heat exchanger; and a
second plate-type heat exchanger, wherein said first and second
heat exchangers are integrally connected to one another.
22. A heat exchanger system of claim 21, wherein said second heat
exchanger comprises: a plurality of stacked plates, with respective
adjacent plates forming pairs of plates, the plates of the pairs
being joined together to define a plurality of third flow channels
therebetween for carrying a third heat exchange medium; and fins
arranged between neighboring pairs of said plates, said fins and at
least one of said neighboring pairs of plates forming a plurality
of fourth flow channels for carrying a fourth heat exchange medium;
wherein said fins are shaped such that the fourth heat exchange
medium has a general flow direction in said fourth flow channels
that is changed as it flows through the second heat exchanger.
23. A heat exchanger system of claim 22, wherein in each of said
first and second heat exchangers, said second and fourth heat
exchange medium is in each case air and said second and fourth flow
channels have a curved course for heat exchange medium flow, and
wherein each of said first and second heat exchangers further
comprises at least one passage aperture for the first and third
heat exchange medium, respectively, and each of said plurality of
second and fourth flow channels are of increasing length with
increasing distance from said respective passage aperture.
24. A heat exchanger system of claim 23, wherein said first and
second heat exchangers are connected to one another only in the
vicinity of said their respective passage apertures.
25. A heating or air conditioning unit comprising: a first
plate-type heat exchanger, said first plate-type heat exchanger
comprising: a plurality of stacked plates, with respective adjacent
plates forming pairs of plates, the plates of the pairs being
joined together to define a plurality of first flow channels
therebetween for carrying a first heat exchange medium; and fins
arranged between neighboring pairs of said plates, said fins and at
least one of said neighboring pairs of plates forming a plurality
of second flow channels for carrying a second heat exchange medium;
wherein said fins are shaped such that the second heat exchange
medium has a general flow direction in said second flow channels
that is changed as it flows through the heat exchanger.
26. A heating or air conditioning unit of claim 25, further
comprising a blower and wherein said first heat exchanger is
positioned downstream of the blower.
27. A heating or air conditioning unit of claim 26, wherein said
blower comprises a radial blower.
28. A heating or air conditioning unit of claim 26, further
comprising: a filter positioned downstream of said blower, and
wherein said first heat exchanger is positioned downstream of said
filter.
29. A heating or air conditioning unit of claim 25, wherein said
first heat exchanger is an evaporator, and the heating or air
conditioning unit further comprising a second heat exchanger
arranged downstream of said evaporator, wherein said second heat
exchanger comprises: a plurality of stacked plates, with respective
adjacent plates forming pairs of plates, the plates of the pairs
being joined together to define a plurality of third flow channels
therebetween for carrying a third heat exchange medium; and fins
arranged between neighboring pairs of said plates, said fins and at
least one of said neighboring pairs of plates forming a plurality
of fourth flow channels for carrying a fourth heat exchange medium;
wherein said fins are shaped such that the fourth heat exchange
medium has a general flow direction in said fourth flow channels
that is changed as it flows through the second heat exchanger.
30. A heating or air conditioning unit of claim 29, wherein said
second heat exchanger is a heater.
31. A heating or air conditioning unit of claim 30, wherein each of
said evaporator and said heater further comprises: at least one
passage aperture for the respective first and third heat exchange
medium, wherein each of said second and fourth flow channels is of
increasing length with increasing distance from said respective
passage aperture.
32. A heating or air conditioning unit of claim 30, wherein said
heater can adjust a flow of said third heat exchange medium.
33. A heating or air conditioning unit of claim 30, further
comprising a bypass positioned downstream of said evaporator for
allowing air to bypass said heater.
34. A heating or air conditioning unit comprising: a first
plate-type heat exchanger; and a second plate-type heat exchanger,
wherein each of said first and second plate-type heat exchangers
comprises: a plurality of stacked plates, with respective adjacent
plates forming pairs of plates, the plates of the pairs being
joined together to define a plurality of first flow channels
therebetween for carrying a first heat exchange medium; and fins
arranged between neighboring pairs of said plates, said fins and at
least one of said neighboring pairs of plates forming a plurality
of second flow channels for carrying a second heat exchange medium;
wherein said fins are shaped such that the second heat exchange
medium has a general flow direction in said second flow channels
that is changed in a circular arcuate path as it flows through each
respective heat exchanger.
35. A heating or air conditioning unit of claim 34, wherein each of
said first and second heat exchangers further comprises: at least
one passage aperture for the first heat exchange medium, and
wherein each of said plurality of second flow channels is of
increasing length with increasing distance from said passage
aperture.
36. A heating or air conditioning unit of claim 35, wherein said
circular arcuate paths of said second flow channels of said first
heat exchanger have a first center located in at least
approximately the same vicinity as a second center of said circular
arcuate paths of said second flow channels of said second heat
exchanger, and wherein said second heat exchanger is a heater.
37. A heating or air conditioning unit of claim 35, wherein each of
said first and second heat exchangers diverts air through
approximately ninety (90) degrees.
38. A heating or air conditioning unit of claim 37, further
comprising an air mixing valve located on downstream of said first
heat exchanger to direct at least a portion of air exiting said
first heat exchanger to said second heat exchanger.
39. A heating or air conditioning unit of claim 34, wherein said
first heat exchanger further comprises an exit face, and said
second heat exchanger comprises an inflow face, wherein said exit
face of said first heat exchanger is aligned approximately parallel
to said inflow face of said second heat exchanger.
40. A heating or air conditioning unit of claim 34, wherein said
first and second heat exchangers are integrally connected to one
another.
41. A heat exchanger of claim 4, wherein said angle is
approximately ninety (90) degrees.
42. A heat exchanger of claim 1, further comprising in each pair of
plates, a plurality of knobs on each said plate arranged opposite
to one another and brazed together to connect said pair of
plates.
43. A method for assembling a heat exchange assembly comprised of a
first plate-type heat exchanger; and a second plate-type heat
exchanger, wherein each of said first and second plate-type heat
exchangers comprises: a plurality of stacked plates, with
respective adjacent plates forming pairs of plates, the plates of
the pairs being joined together to define a plurality of first flow
channels therebetween for carrying a first heat exchange medium;
and fins arranged between neighboring pairs of said plates, said
fins and at least one of said neighboring pairs of plates forming a
plurality of second flow channels for carrying a second heat
exchange medium, wherein said fins are shaped such that the second
heat exchange medium has a general flow direction in said second
flow channels that is changed as it flows through each respective
heat exchanger, comprising: assembling a stack of said plates for
said first heat exchanger in alignment with one another and a stack
of said plates for said second heat exchanger in alignment with
each other, wherein at least some of the plates of said first heat
exchanger are connected to corresponding plates of said second heat
exchanger; during said stack assembling, interposing said fins
between each neighboring pair of plates for forming said second
flow channels; and brazing each of said pair of plates together on
at least their outer circumference to form said first flow channels
and brazing said fins to adjacent pairs of plates to form said
second flow channels, whereby said first and second heat exchangers
are produced in a single assembly operation.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a heat exchanger of a
plate-type construction, and a heating or air conditioning unit for
a motor vehicle equipped therewith.
[0002] An air conditioning unit as disclosed, for example, in DE
198 04 389 has an evaporator of what is referred to as a plate-type
construction. The evaporator has first flow channels, each formed
from a pair of plates, for a coolant of the air conditioning unit,
and corrugated fins, around which the air to be cooled flows,
arranged in each case between neighboring plate pairs. Such known
plate-type evaporators, as they are called, are of cuboid
construction and are used in the air conditioning unit between a
fan and a heater to cool the air to be passed into the passenger
compartment.
[0003] Motor vehicles today are intended to be as compact as
possible in their external dimensions, the interior space being as
large as possible. Accordingly, efforts are made to design
increasingly compact air conditioning units, so that they take up
as little structural space as possible. Designers therefore attempt
to make the individual components of the air conditioning unit
smaller and more efficient, as shown, for example, by DE 197 19
252, in which the evaporator described is designed such that its
overall depth is no more than 50 mm.
SUMMARY OF THE INVENTION
[0004] It is an object of the invention to provide an improved heat
exchanger and a heating or air conditioning unit equipped therewith
which has a reduced structural volume.
[0005] It is also an object of the invention to provide an improved
method of assembling a heat exchanger assembly that includes plural
heat exchangers.
[0006] In accomplishing the objects of the invention, there has
been provided in accordance with one aspect of the invention a
plate-type heat exchanger comprising: a plurality of stacked
plates, with respective adjacent plates forming pairs of plates,
the plates of the pairs being joined together to define a plurality
of first flow channels therebetween for carrying a first heat
exchange medium; and fins arranged between neighboring pairs of
said plates, said fins and at least one of said neighboring pairs
of plates forming a plurality of second flow channels for carrying
a second heat exchange medium, wherein said fins are shaped such
that the second heat exchange medium has a general flow direction
in said second flow channels that is changed as it flows through
the heat exchanger.
[0007] In accordance with another aspect of the invention, there
has been provided a heating or air conditioning unit comprising: a
first plate-type heat exchanger; and a second plate-type heat
exchanger, wherein one or both of said first and second plate-type
heat exchangers comprises: a plurality of stacked plates, with
respective adjacent plates forming pairs of plates, the plates of
the pairs being joined together to define a plurality of first flow
channels therebetween for carrying a first heat exchange medium;
and fins arranged between neighboring pairs of said plates, said
fins and at least one of said neighboring pairs of plates forming a
plurality of second flow channels for carrying a second heat
exchange medium, wherein said fins are shaped such that the second
heat exchange medium has a general flow direction in said second
flow channels that is changed as it flows through each respective
heat exchanger.
[0008] According to still another aspect of the invention, there
has been provided a method for assembling a heat exchange assembly
comprised of a first plate-type heat exchanger; and a second
plate-type heat exchanger, wherein each of said first and second
plate-type heat exchangers comprises: a plurality of stacked
plates, with respective adjacent plates forming pairs of plates,
the plates of the pairs being joined together to define a plurality
of first flow channels therebetween for carrying a first heat
exchange medium; and fins arranged between neighboring pairs of
said plates, said fins and at least one of said neighboring pairs
of plates forming a plurality of second flow channels for carrying
a second heat exchange medium, wherein said fins are shaped such
that the second heat exchange medium has a general flow direction
in said second flow channels that is changed as it flows through
each respective heat exchanger, comprising: assembling a stack of
said plates for said first heat exchanger in alignment with one
another and a stack of said plates for said second heat exchanger
in alignment with each other, wherein at least some of the plates
of said first heat exchanger are connected to corresponding plates
of said second heat exchanger; during said stack assembling,
interposing said fins between each neighboring pair of plates for
forming said second flow channels; and brazing each of said pair of
plates together on at least their outer circumference to form said
first flow channels and brazing said fins to adjacent pairs of
plates to form said second flow channels, whereby said first and
second heat exchangers are produced in a single assembly
operation.
[0009] Further objects, features and advantages of the present
invention will become apparent from the detailed description of
preferred embodiments that follows, when considered together with
the accompanying figures of drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The invention is explained in detail below with reference to
exemplary embodiments, and with reference to the accompanying
drawings, in which:
[0011] FIG. 1 shows a perspective view of a heat exchanger
according to the invention;
[0012] FIG. 2 shows a pair of plates with a neighboring corrugated
fin;
[0013] FIG. 2a shows a partial cross section in the edge region of
the heat exchanger according to the invention;
[0014] FIG. 3 shows a plan view of a plate;
[0015] FIG. 4 shows a plate with a neighboring corrugated fin of a
system consisting of two heat exchangers;
[0016] FIG. 5 shows a plate with a corrugated fin corresponding to
FIG. 4 of another embodiment;
[0017] FIG. 6 shows an air conditioning unit according to the
invention having a heat exchanger according to the invention as an
evaporator;
[0018] FIG. 7 shows an air conditioning unit according to the
invention with an evaporator and heater designed according to the
invention;
[0019] FIG. 8 shows a further embodiment of an air conditioning
unit according to the invention with temperature control on the air
side; and
[0020] FIG. 9 shows an air conditioning unit according to the
invention with temperature control on the water or coolant
side.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0021] According to the invention, the corrugated fins and at least
one of the neighboring plate pairs form second flow channels for a
second heat exchange medium, for example, for air, which flows
through the heat exchanger, the second flow channels having a
curved course, so that the second heat exchange medium undergoes a
change of flow direction on flowing through the heat exchanger.
With such a heat exchanger, which no longer has to be of cuboid
construction and through which the air does not flow in a linear
manner, the air need not, as previously in known air conditioning
units, be deflected upstream and downstream of the heat exchanger.
Instead, the air is deflected directly in the heat exchanger as it
flows through. The heat exchanger performs both the function of
cooling or heating the air flowing through, depending on the
intended purpose, and the function of guiding the air. As a result,
at least to a certain extent, air deflections on the air side is
upstream and/or downstream of the heat exchanger can be dispensed
with, and the heating or air conditioning unit, or the air guide
housing of that unit, can be of more compact design.
[0022] Advantageous embodiments of the invention are described
herein.
[0023] When the air undergoes a change of direction in the heat
exchanger, an air inflow face and an air exit face of the heat
exchanger are non-parallel and are advantageously arranged at an
angle .alpha. to one another. The angle .alpha. depends on the
degree to which it is desired to change the direction of air flow
in each application. Typically, the angle .alpha. is greater than
30.degree. and less than 150.degree., more typically from
60.degree. to 120.degree.. For many applications, the angle .alpha.
is preferably approximately 90.degree..
[0024] In one embodiment of the invention, the individual second
flow channels are of different lengths, and it is particularly
advantageous if the second flow channels become longer with
increasing distances from a feed for the first heat exchange
medium, so that in the vicinity of the feed, where a relatively
large temperature difference exists between the two media, the
second flow channels are relatively short and therefore the heat
exchange only needs to take place over a shorter path. At a greater
distance from the feed, the temperature difference between the two
media becomes smaller and therefore the flow channels are
advantageously longer, so that the air, which is guided in the heat
exchanger independently of the position of the second flow channel
into a particular flow channel, is always brought to the same
temperature level.
[0025] Advantageously, for flow purposes, the second flow channels
preferably have an arcuate course, especially a circular arcuate
course. As a result, pressure losses for the air are reduced,
despite deflection.
[0026] The first flow channels preferably have a serpentine course
in order to optimize heat exchange with the second heat exchange
medium.
[0027] In a structurally simple manner, the corrugated fins may be
punched from sheet metal.
[0028] If two heat exchangers are to be used, for example an
evaporator and a heater in an air conditioning unit, and the two
heat exchangers are connected in series on the air side, it is
advantageous if both heat exchangers are designed according to the
invention and the is plates of the two heat exchangers are
integrally connected to one another. Then the two heat exchangers
can be produced simultaneously in a single production process by
jointly arranging in series and brazing the plates and corrugated
fins. In the further assembly of the air conditioning unit, also,
advantages are achieved in that the heat exchangers can be
simultaneously inserted as one unit into the air conditioning unit.
Overall, this can save numerous assembly steps.
[0029] In order nevertheless to decouple the two heat exchangers
thermally as far as possible, it is advantageous if the plates of
the heat exchangers are connected to one another only in the region
of their passage apertures, which in each case form collection
spaces for the first heat exchange medium. As a result, a further
advantage is also achieved that water of condensation forming in
the heat exchanger which is used as an evaporator can run off
better between the heat exchangers.
[0030] Particularly advantageously, the heat exchanger according to
the invention can be used in a heating or air conditioning unit as
an evaporator and/or heater, since structural space can thus be
saved in the manner already described. In this case, the air
conditioning unit can either be adjustable on the coolant side,
e.g., by having the flow of the first heat exchange medium through
the heater be adjustable, or the heating or air conditioning unit
can be adjusted on the air side, in which case a heater bypass is
provided on the air side. In an air conditioning unit which has an
evaporator and/or heater of the structure according to the
invention, the air is deflected less frequently and with a reduced
pressure loss, and there is reduced disruption to the airflow. By
adjustment on the air side, the separation of the partial streams
of air downstream of the heater will be relatively great. This
means that there is less mixing of cold and warm air and the
temperature differences over the cross section of the airflow
downstream of the heater are relatively great. This can be
exploited in a desirable manner to pass warmer air to a foot space
and a windshield and the colder air to outlets in the central plane
of the vehicle.
[0031] A very compact heating or air conditioning unit is obtained
if the heat exchanger or heat exchangers each divert the air
through approximately 90.degree..
[0032] Turning now to the drawings, a heat exchanger 10 according
to the invention, as shown in the figures, has first and second
plates 12 and 14, which in each case form a plate pair 16 and are
connected, for example, brazed, to one another at least at the
edges and thereby form first flow channels 18 between them in each
case for a first heat exchange medium (FIG. 2a). Corrugated fins 20
are arranged in each case between two neighboring plate pairs 16.
The corrugated fins 20 are connected, especially brazed, to their
neighboring plate pairs 16, so that the corrugated fins 20 and at
least one of the neighboring plate pairs 16 form second flow
channels 22 for a second heat exchange medium. In the embodiment
shown, the second flow channels have a rectangular cross section
because of the shape of the corrugated fin 20. Other shapes are
conceivable, such as depending on the form of corrugation of the
corrugated fin 20. When the first heat exchange medium flows
through the heat exchanger via the first flow channels and the
second heat exchange medium via the second flow channels, heat
exchange takes place between the media.
[0033] The plates 12 and 14 have approximately the shape of a
quarter-circle and have two passage apertures 26 and 28 at an end
24 facing a center of the circle, each passage aperture 26 and 28
having a collar, 30 and 32 respectively, so that in the assembled
state of the heat exchanger the collars of neighboring plate pairs
can be connected, especially brazed, to one another so that the
mutually flush passage apertures 26 and 28 in each case form a
collection space for the first heat exchange medium. The first heat
exchange medium is fed to or removed from the heat exchanger via a
feed 34 or outlet 36.
[0034] The first flow channels 18 are open toward the inlet
apertures 26 and outlet apertures 28, so that the first heat
exchange medium can flow in from the feed 34 and thus through the
passage apertures 26 into all flow channels 18 in parallel and can
flow from the flow channels 18 into the passage apertures 28 and to
the outlet 36. Within a plate pair 16, the flow channel 18 has a
serpentine course, which is produced by webs 40, 42, 44 extending
radially from the passage apertures (FIG. 3). The serpentine flow
course of the first heat exchange medium is indicated by the arrows
46 in FIG. 3. In order to enable the flow channels 18 formed by the
plates 12 and 14 to have a more pressure-stable design, knobs or
protrusions 13 are additionally provided, as required, these being
shown only in one sub-area in FIG. 3. The knobs 13 of the plates 12
and 14 are arranged opposite one another in pairs (FIG. 2) and
brazed to one another, and they prevent the plates 12 and 14 from
bending away or toward one another.
[0035] The second heat exchange medium, which in preferred intended
uses of the invention is air, flows through the second flow
channels 22. Channels 22 have a curved course, especially a
circular arcuate course, in accordance with the shape of the plate
pairs 16 and corrugated fins 20, so that each flow channel 22
describes a quarter-arc, the flow channels 22 having different
lengths and the flow channels 22 becoming longer as the radial
distance from the passage apertures 26 and 28 respectively becomes
greater (FIG. 2).
[0036] The heat exchanger 10 according to the invention, in whose
second flow channels the second heat exchange medium undergoes a
change of flow direction, has an inflow face 50 for the second heat
exchange medium, arranged at an angle a of preferably approximately
90.degree. to an exit face 52 for the second heat exchange medium,
as is shown in FIG. 1, in which the airflow is represented by
arrows 53 and 54. If the flow direction of the second heat exchange
medium is to be changed by more or less than 90.degree. in any
given application, the angle a may have a correspondingly different
value.
[0037] If two heat exchangers according to the invention are to be
arranged in series in the flow direction of the second heat
exchange medium, the individual plates 12 and 14 may be connected
to one another, as is shown in the embodiments according to FIGS. 4
and 5. The first flow channels of the first heat exchanger 10
should not be in fluid connection with the first flow channels of
the second heat exchanger 10'. In principle, the second flow
channels 22 of the first heat exchanger 10 may be integral with the
second flow channels 22' of the second heat exchanger 10', the
corrugated fin 20 being continuous and consisting of a single piece
for the two heat exchangers 10 and 10'. However, it is advantageous
for purposes of thermal decoupling for the corrugated fin to be
separated into two corrugated fins 20 and 20' for the heat
exchanger 10 and for the heat exchanger 10', as shown in FIG. 4.
Further thermal decoupling may be achieved if the plates 12 and 14
are connected only in the region of the passage apertures 26 and 28
or 26' and 28', respectively, as shown in FIG. 5.
[0038] The heat exchanger 10 according to the invention is
preferably used in heating or air conditioning units. FIG. 6
illustrates an exemplary embodiment, in which the heat exchanger is
used as an evaporator 102. Air to be conditioned is directly fed by
a radial fan 104 (not shown in detail) to the inflow face 106 of
the evaporator 102. In the evaporator 102, the air is cooled and
simultaneously deflected in the direction of an air mixing space
108, in which the air cooled in the evaporator 102 can be mixed
with air warmed in a heater 110 of a conventional type. Via a
mixing valve 112, part of the cold air emerging from the exit face
114 of the evaporator 102 can be removed toward the heater 110 and,
via a warm air channel 116, passed to the air mixing space 108 as
warm air. From the air mixing space 108, some of the air is passed
via a defrosting air channel 118 and a defrosting air valve 120 to
the windshield. Via a foot space air channel 122 and a foot space
air valve 124, air can be fed to a foot space. An air channel for
guiding air to outlets in a central plane of the passenger
compartment is not specifically shown in FIG. 6, but is generally
present.
[0039] The hatched surface 130 shown above the fan 104 in FIG. 6
represents the space that can be saved by using the heat exchanger
102 according to the invention instead of a conventional cuboid
evaporator.
[0040] The structural volume of the heating or air conditioning
unit according to the invention can be further reduced if, as shown
in FIG. 7, the heater is also designed according to the invention
and thus able not only to warm the air but also to deflect it.
[0041] A further substantial reduction in structural volume is
obtained if both the evaporator 102 and the heater 110' are
designed according to the invention, and thus not only condition
the air but can also deflect it and, at the same time, are arranged
in series on the airflow side, as shown in the exemplary embodiment
according to FIG. 8. The evaporator 102 is installed directly
downstream of the fan 104, and the heater 110' is again fitted
downstream of the evaporator 102, the inflow face 140 of the heater
110' being aligned approximately parallel to the air exit face 114
of the evaporator 102. The second flow channels of the evaporator
102 and of the heater 110', having a circular arcuate shape, then
extend in such a way that the centers of the circles of the
circular arcuate courses are located at least approximately in the
same vicinity. In this embodiment, air is passed from the outlet
150 of the fan 104 to the air mixing space 108 on a circular
arcuate path and uniformly deflected by only 180.degree. and in a
manner favoring flow, as a result of which smaller pressure losses
are achieved.
[0042] A mixing valve 112 is arranged between the air inflow face
140 and the air exit face 115 114, and adjusts the quantity of air
passed to the heater 110'. Pneumatically parallel to the heater
110' on the airflow side is a heater bypass 142, which can be
closed via a bypass valve 144. Thus, cold air cooled in the
evaporator can be guided past the heater and passed to the air
mixing space 108. The warm air emerging at the air exit face 146 of
the heater 110' likewise enters the air mixing space and can mix
with the cold air present there. Branching off from the air mixing
space 108 are the defrosting air channel 118, the foot space air
channel 122 and an air channel 148 which leads to outlets in the
central plane of the vehicle. The air channels branching off from
the air mixing space 108 can in each case be shut off by means of
air valves.
[0043] In a further embodiment of the invention, shown in FIG. 9,
the evaporator 102 and the heater 110' are again both designed in
accordance with the invention. In this case, the heater 110' and
the evaporator 102 are arranged in series on the air side without
an interposed air flap. All the air initially flows through the
evaporator 102 and is cooled there, and then through the heater
110', where it is reheated as necessary. To regulate the air
temperature, the flow of the first heat exchange medium through the
heater 110' is adjustable. This first heat exchange medium is
generally the coolant of the internal combustion engine of the
motor vehicle. In this embodiment of the heating or air
conditioning unit according to the invention, the system has two
heat exchangers designed as shown in FIGS. 4 and 5. These heat
exchangers connected to one another and produced in a single
production process, which was described earlier, and can be used
with particular advantage. In this case, again, the second flow
channels of the evaporator 102 and of the heater 110', having a
circular arcuate shape, extend in such a way that the centers of
the circles represented by the circular arcuate courses are located
at least approximately in the same vicinity. In this case, again,
the air is uniformly deflected by only 180.degree. from the outlet
of the radial fan 104 to the space 108' downstream of the heater
110' on the airflow side. From the space 108', the conditioned air
is passed in a known manner via air valves and the individual air
channels to the passenger compartment.
[0044] The disclosure of German priority patent application number
DE 100 10 266.2, filed Mar. 2, 2000, is hereby incorporated by
reference in its entirety.
[0045] The foregoing embodiments have been shown for illustrative
purposes only and are not intended to limit the scope of the
invention, which is defined by the claims.
* * * * *