U.S. patent application number 10/575890 was filed with the patent office on 2007-03-15 for heat exchanger in particular for motor vehicles.
This patent application is currently assigned to Walter Demuth etal. Invention is credited to Walter Demuth, Michael Kohl, Martin Kotsch, Michael Kranich, Karl-Heinz Staffa, Christoph Walter.
Application Number | 20070056720 10/575890 |
Document ID | / |
Family ID | 34442203 |
Filed Date | 2007-03-15 |
United States Patent
Application |
20070056720 |
Kind Code |
A1 |
Demuth; Walter ; et
al. |
March 15, 2007 |
Heat exchanger in particular for motor vehicles
Abstract
The invention relates to a heat exchanger (1), in particular for
a motor vehicle, comprising a heat exchange assembly with a primary
side, through which a first medium flows and a secondary side,
through which a second medium flows and a housing sleeve with an
inlet and an outlet for a second medium.
Inventors: |
Demuth; Walter; (Gerlingen,
DE) ; Kohl; Michael; (Bietigheim, DE) ;
Kotsch; Martin; (Ludwigsburg, DE) ; Kranich;
Michael; (Besigheim, DE) ; Staffa; Karl-Heinz;
(Stuttgart, DE) ; Walter; Christoph; (Stuttgart,
DE) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
Walter Demuth etal
|
Family ID: |
34442203 |
Appl. No.: |
10/575890 |
Filed: |
September 10, 2004 |
PCT Filed: |
September 10, 2004 |
PCT NO: |
PCT/EP04/10158 |
371 Date: |
August 6, 2006 |
Current U.S.
Class: |
165/158 |
Current CPC
Class: |
F28D 7/1692 20130101;
F25B 2309/061 20130101; F28F 3/025 20130101; F28F 9/0278 20130101;
F25B 9/008 20130101; F25B 39/02 20130101 |
Class at
Publication: |
165/158 |
International
Class: |
F28F 9/02 20060101
F28F009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 17, 2003 |
DE |
10349150.3 |
Claims
1. A heat exchanger, in particular for a motor vehicle, having a
heat exchanger block which has pipes through which a first medium
can flow on the primary side, and pipes around which a second
medium can flow on the secondary side, said pipes having flow ducts
and pipe ends, at least one end piece which holds the pipe ends and
each have at least one base plate, diverter plate and cover plate
as well as at least one inlet chamber and/or outlet chamber which
is connected to one, or in each case to one, end piece, it being
possible to conduct the first medium from the inlet chamber to the
outlet chamber through the flow ducts, and with a housing casing
which surrounds the pipes and has an inlet and an outlet for the
second medium.
2. The heat exchanger as claimed in claim 1, wherein the pipes are
embodied in particular as extruded flat pipes.
3. The heat exchanger as claimed in claim 1, wherein the pipes each
have a plurality of flow ducts.
4. The heat exchanger as claimed in claim 1, wherein the heat
exchanger block has at least two end pieces.
5. The heat exchanger as claimed in claim 1, wherein the housing
casing is arranged between two end pieces.
6. The heat exchanger as claimed in claim 1 wherein at least two
plates of an end piece are embodied in an integral fashion.
7. The heat exchanger as claimed in claim 1, wherein the housing
casing is embodied as a single-part or multipart sheet-metal
casing.
8. The heat exchanger as claimed in that claim 1, wherein the
housing casing is connected in a materially joined fashion, in
particular soldered, to the at least one end piece.
9. The heat exchanger as claimed in claim 1, wherein the housing
casing has an essentially rectangular cross section with four
sides.
10. The heat exchanger as claimed in claim 1, wherein the inlet and
the outlet are arranged on opposite sides of the housing
casing.
11. The heat exchanger as claimed in claim 1, wherein the inlet and
the outlet are arranged on the same side of the housing casing.
12. The heat exchanger as claimed in claim 1, wherein the inlet and
the outlet are arranged at opposite ends of the housing casing.
13. The heat exchanger as claimed in claim 1, wherein distributor
and collector chambers are formed in the housing casing in the
region of the inlet and outlet.
14. The heat exchanger as claimed in claim 1, wherein corrugated
pieces of sheet metal with longitudinal ducts are arranged between
the pipes.
15. The heat exchanger as claimed in claim 14, wherein the
corrugated pieces of sheet metal have a longitudinal extent which
corresponds to the distance between the inlet and outlet.
16. The heat exchanger as claimed in claim 1, wherein the
corrugated pieces of sheet metal are embodied in a rectangular
shape and leave an approximately rectangular inflow and outflow
region between the pipes.
17. The heat exchanger as claimed in claim 1, wherein the
corrugated pieces of sheet metal are embodied in the form of a
parallelogram and leave approximately triangular or trapezoidal
inflow and outflow regions between the pipes.
18. The heat exchanger as claimed in claim 1, wherein the inlet and
the outlet are arranged opposite one another, and in that a
dividing wall is left between the inlet and outlet in order to form
an inflow region and an outflow region, and a diverter section is
left at the end of the housing casing facing away from the inlet
and outlet, and in that the housing casing can be configured for at
least a dual flow in the longitudinal direction on the secondary
side.
19. The heat exchanger as claimed in claim 1, wherein the second
medium is guided essentially transversely with respect to the
longitudinal direction of the pipes through the block.
20. The heat exchanger as claimed in claim 19, wherein the second
medium can be diverted at least once in the longitudinal direction,
and the heat exchanger block can be configured for at least dual
flow.
21. The heat exchanger as claimed in claim 1, wherein the housing
casing with the pipes and the block forms an inlet chamber and an
outlet chamber for the second medium, which chambers extend in the
longitudinal direction of the pipes.
22. The heat exchanger as claimed in claim 21, wherein inlet and
outlet ducts for the second medium are arranged at the end pieces,
said inlet and outlet ducts communicating with the inlet and outlet
chambers.
23. The heat exchanger as claimed in claim 1, wherein at least one
diversion box is arranged in the housing casing, and at least one
transversely extending dividing wall is arranged between the
pipes.
24. The heat exchanger as claimed in claim 1, wherein corrugated
ribs or turbulence inserts which form transverse ducts for the
second medium are arranged between the pipes.
25. The heat exchanger as claimed in claim 1, wherein the heat
exchanger block is configured for a single flow on the primary
side.
26. The heat exchanger as claimed in claim 1, wherein the heat
exchanger block can be configured for a dual flow or more on the
primary side.
27. The heat exchanger as claimed in claim 1, wherein the first
medium is a refrigerant which can be operated in particular in dual
phase or supercritically.
28. The heat exchanger as claimed in claim 1, wherein the second
medium is a fluid, and in particular a fluid coolant.
Description
[0001] The invention relates to a heat exchanger, in particular for
motor vehicles, having a heat exchanger block through which a first
medium can flow on the primary side, and around which a second
medium can flow on the secondary side.
[0002] Such a heat exchanger is described in DE102 60 030 A1. The
heat exchanger in said document is composed, inter alia, of flat
pipes with flow ducts, for example extruded multi-chamber pipes,
through which a first medium, preferably a refrigerant, in
particular CO.sub.2 flows. The flat pipes are arranged parallel to
one another and have flat pipe ends which are secured in what are
referred to as end pieces, composed of a base plate, a diverter
plate and a cover plate. The end pieces each form a distributor
unit or diverter unit for the refrigerant. The refrigerant is fed
in via a collector pipe which is connected to an end piece--the
refrigerant is discharged in an analogous fashion via a further
collector pipe which is attached either to the same end piece or to
the end piece located opposite. This design provides a particularly
pressuretight heat exchanger which can be used in particular for
use in a refrigerant circuit, operated with CO.sub.2 for a motor
vehicle air conditioning system, specifically both as a vaporizer
and as a gas cooler, ambient air being respectively supplied on the
secondary side.
[0003] In contrast with this, the object of the present invention
is to extend the application possibilities of such a heat
exchanger.
[0004] This object is achieved by means of the features of patent
claim 1. According to the invention, a heat exchanger block,
composed of pipes and at least one end piece, is surrounded by a
housing casing through which a second medium can be conducted. As a
result, further possibilities of use for the heat exchanger
according to the invention, in particular in a heat pumping process
with the refrigerant CO.sub.2, are obtained using the heat
exchanger block which is described in DE 102 60 030 A1, for
example, whose content is herewith expressly incorporated in the
contents of the disclosure, and a housing casing which is
relatively easy to manufacture. Consumption-optimized engines
supply too little heat energy so that these vehicles require an
additional heater, referred to as a supplementary heater. The
coolant for the coolant circuit of the engine is used here as a
heat source. The heat exchanger according to the invention can be
used in this heat pump circuit both as a CO.sub.2 vaporizer, which
absorbs heat from the coolant, and as a CO.sub.2 gas cooler which
transfers heat to the coolant. The housing casing which can be
manufactured as a sheet-metal component permits many variation
possibilities for the guidance of the flow of the coolant so that a
parallel flow, counter flow, cross flow as well as
parallel/counter-cross flow is possible. As a result, it is
possible to make allowance for the various requirements made of the
heat exchangers according to the invention.
[0005] Further refinements of the invention are specified in the
subclaims.
[0006] According to advantageous refinements of the invention, the
inlet and the outlet for the second medium can be arranged on the
same side, on opposite sides and at opposite ends of the housing
casing, there being in particular a flow through the housing casing
in the longitudinal direction. This results in the possibility of
the parallel flow and the counter flow of the first and second
media.
[0007] According to one advantageous development of the invention,
distributor and collector chambers are formed in the housing casing
in the region of the inlet and outlet so that the second medium is
distributed uniformly over the individual gaps between the pipes
and/or collected at the outlet.
[0008] According to a further refinement of the invention, what are
referred to as turbulence inserts or corrugated ribs are arranged
between the pipes and form longitudinal ducts as well as a guide in
the longitudinal direction of the pipes for the second medium.
These turbulence inserts preferably extend only between the inlet
and the outlet of the second medium so that in each case an inflow
region and an outflow region are left in the vicinity of the inlet
and outlet and there can be a cross flow of the second medium, i.e.
transverse with respect to the longitudinal direction of the pipes,
in said regions.
[0009] According to a further advantageous refinement of the
invention, the second medium can also flow across the pipes in the
transverse direction, specifically in a single flow or multiple
flow. This can be done by arranging lateral collector boxes and
dividing walls in conjunction with diversion boxes in the housing
casing. The turbulence inserts and the ribbing between the pipes is
then configured in such a way that transverse ducts for guiding the
second medium are produced. This ensures that both media for
example a refrigerant and a coolant, can be guided in the
cross-parallel flow or cross-counter flow modes. This produces a
more intensive exchange of heat.
[0010] In a further advantageous refinement of the invention, there
can either by a single flow or a dual flow of the first medium
through the pipes, the inlet and outlet chambers for the first
medium being arranged either at an end piece or at various end
pieces. As a result, a wide variety of shapes and combinations of
parallel flow, counter flow and cross flow between the first and
second media can be implemented with the heat exchanger according
to the invention depending on the requirements made of the heat
exchanger, for example in a refrigerant circuit and in a coolant
circuit of an internal combustion engine of a motor vehicle.
[0011] Exemplary embodiments of the invention are illustrated in
the drawing and will be explained in more detail below. In the
drawing:
[0012] FIG. 1 shows a refrigerant/coolant heat exchanger with a
housing casing,
[0013] FIG. 1a shows the heat exchanger according to FIG. 1 without
a housing casing,
[0014] FIG. 1b shows the heat exchanger according to FIG. 1a in an
exploded illustration,
[0015] FIG. 1c shows a schematic illustration of the refrigerant
circuitry,
[0016] FIG. 2 shows a heat exchanger with obliquely indented
ribbing and diversion of the refrigerant (dual flow),
[0017] FIG. 2a shows the heat exchanger according to
[0018] FIG. 2 but without diversion of the refrigerant (single
flow),
[0019] FIG. 3 shows a heat exchanger with ribbing which is indented
at right angles and with dual flow of the refrigerant,
[0020] FIG. 3a shows the heat exchanger according to FIG. 3 but
with single flow of the refrigerant,
[0021] FIG. 4 shows a heat exchanger with dual flow of the coolant
in the longitudinal direction,
[0022] FIG. 5 shows a cross section through a heat exchanger with a
view of the end sides of the flat pipes,
[0023] FIG. 6 shows a longitudinal section through a flat pipe with
end pieces,
[0024] FIG. 7 shows a further exemplary embodiment of a heat
exchanger with transversely directed coolant, and
[0025] FIG. 8 shows a further exemplary embodiment of a heat
exchanger with transversely directed coolant flow which is diverted
twice.
[0026] FIG. 1 shows a refrigerant/coolant heat exchanger 1, i.e. a
heat exchanger, through which a refrigerant flows, for example
CO.sub.2 (R744) on the primary side and a coolant flows on the
secondary side, said coolant serving at the same time to cool an
internal combustion engine (not illustrated) of a motor vehicle. As
a result, the coolant circuit of the internal combustion engine and
the refrigerant circuit of the air conditioning system of a vehicle
have a heat-exchanging connection to one another via this heat
exchanger. The refrigerant circuit can be used as a heat source for
additionally heating the passenger compartment when said circuit is
operated in the heat pumping process. In this context, heat is
extracted from the coolant in the vaporizer, "pumped" to a
relatively high temperature level and returned to the coolant as
input heat in the gas cooler. The heated coolant then outputs this
heat to ambient air via a heating element (not illustrated), said
air being fed as warm air to the passenger compartment of the
vehicle. In this respect, this heat exchanger 1 can be used both as
a vaporizer and as a gas cooler in the CO.sub.2 heat pumping
process. The CO.sub.2 process is known to take place under high
pressure compared to the conventional refrigerant process with
R134a; for example compression to approximately 120 bar takes
place, said compression thus occurring in the gas cooler. For this
reason, the heat exchanger must be dimensioned and constructed in a
particularly pressuretight fashion with respect to the conduction
of the refrigerant.
[0027] The heat exchanger 1 has a housing casing 2 which is
embodied approximately in the form of a box and has four
longitudinal sides 2a-2d, the longitudinal sides 2a and 2b of which
can be seen in the drawing. The housing casing 2 is closed off at
the ends by end pieces, only the end piece 3 of which can be seen
in the drawing. The refrigerant inlet pipe 4 and a refrigerant
outlet pipe 5 are attached to this end piece 3. A coolant inlet
connector 6 (only partially visible) and a coolant outlet connector
7 are arranged on opposite sides of the housing casing 2. As
already mentioned, the heat exchanger 1 is connected at one end to
a refrigerant circuit, in particular a CO.sub.2 circuit (not
illustrated) and at the other end to a coolant circuit (not
illustrated) of an internal combustion engine of a motor
vehicle.
[0028] FIG. 1a shows the heat exchanger 1 according to FIG. 1
without a housing casing 2, identical reference numerals being used
for identical parts. An end piece 8, which is connected to the end
piece 3 by a plurality of flat pipes 9, is located opposite the end
piece 3 to which the refrigerant collector pipes 4, 5 are attached.
A corrugated piece of sheet metal 10 with longitudinal ducts 10a
which extend in the longitudinal direction of the flat pipes 9 is
arranged on the top flat pipe 9.1. The profile of the corrugated
piece of sheet metal can, as illustrated in the drawing, be of
trapezoidal design but can also have other forms, for example a
sinusoidal or triangular section. The corrugated piece of sheet
metal 10 does not extend over the entire length of the flat pipes 9
from the left-hand end piece 3 as far as the right-hand end piece 8
but rather has in each case an oblique indented edge 10b, 10c at
the ends. Corrugated pieces of sheet metal 10 are (not visible in
this illustration) each arranged between adjacent flat pipes 9 so
that in these regions the coolant is guided longitudinally.
Likewise, the corrugated pieces of sheet metal can also be provided
with slots and/or offsets so that exchange is possible between the
longitudinal guiding ducts for the coolant so that more homogenous
distribution and/or turbulences of the coolant and ultimately an
increased transfer of heat are possible. Pieces of sheet metal with
transversely extending coolant ducts can also be used to make the
surface larger and thus increase the efficiency of the heat
exchanger.
[0029] In the regions which remain free owing to the oblique
indents 10b, 10c, transverse flow of the coolant is possible. The
refrigerant (which is explained in more detail below) flows from
the inlet pipe 4 via the end piece 3, which acts as a distributor
unit, to the flat pipes 9 as far as the second end piece 8 which
act as a diverter unit, and back to the outlet pipe 5 through the
flat pipes 9. This refrigerant unit is referred to as a heat
transfer block 11 or as block 11 for short.
[0030] FIG. 1b shows the heat exchanger block 11 in an exploded
view. Here too, identical reference numerals are used again for
identical parts. It is to be noted that a number of possibilities
for the guidance of the flow of refrigerant are described in DE 102
60 030 A1, to be precise both in the embodiment illustrated here as
well as in further embodiments and modifications. DE 102 60 030 A1
is thus incorporated in its entire extent into the disclosure
contents of this application. Block 11 is composed of a plurality
of flat pipes 9 which are arranged parallel to one another and have
flat pipe ends 9a, 9b which are each attached in a base plate 12,
13 and sealed. In each case distributor or diverter plates 14, 15
are arranged above the base plates 12, 13 and are each covered by a
closure plate 16, 17. Refrigerant inlet openings 16a and
refrigerant outlet openings 16b are arranged in series with the
refrigerant inlet pipe 4 and the refrigerant outlet pipe 5 in the
front cover plate 16. The base plate 12, diverter plate 14 and
cover plate 16 thus form the end piece 3, while the end piece 8 is
composed of the base plate 13, the diverter plate 15 and the cover
plate 17. As stated in the application which predates the priority
date of this document, the design of the end pieces 3, 8 can also
be modified, for example the base and diverter plates or diverter
and cover plates can each be integrated to form one plate. The same
applies to the guidance of the refrigerant, i.e. by means of a
modified form of the distributor or diverter plates 14, 15.
[0031] FIG. 1c is a schematic illustration of the refrigerant
circuitry, i.e. the guidance of the flow of refrigerant according
to FIG. 1b. For details, reference should be made to the
application whose priority date predates this application and
which, as stated above, has been incorporated entirely into the
subject matter of this application. The refrigerant which enters
via the refrigerant inlet pipe 4 and is distributed via the inlet
openings 16a passes into the flat pipes 9, i.e. their right-hand
section 18, is diverted in the direction of the arrow 19 in the
diverter unit or the end piece 8 by means of the diverter plate 15
and then passes back to the base plate 12 in the adjacent flat
pipe, in its right-hand section 20, and is guided in the direction
of the arrow 21 by means of the diverter plate 14 on the left-hand
section 22. As a result, the refrigerant passes back to the end
piece 8 where it is diverted upwards by means of the diverter plate
15 in the direction of the arrow 23 in order to flow back again in
the section 24. The refrigerant leaves the block 11 via the
diverter plate 14, the refrigerant outlet opening 16b and the
refrigerant outlet pipe 5. The refrigerant outlet opening 16b are
larger than the refrigerant inlet openings 16a because this block
11 is configured as a vaporizer (with an increasing specific
volume); in a gas cooler there would be a different configuration,
for example with identical inlet and outlet openings. The
refrigerant circuitry described above therefore respectively
applies for two flat pipes lying one next to the other.
[0032] As already mentioned and stated in the application whose
priority date predates that of this document, other refrigerant
circuitry variants are possible.
[0033] FIG. 2 shows a refrigerant/coolant heat exchanger 25 in
longitudinal section, which corresponds to the heat exchanger 1 in
FIG. 1; identical reference numerals being used for identical
parts. The housing casing 2 surrounds the entire block 11 composed
of flat pipes 9 and end pieces 3, 8, the housing casing 2 having,
in the region of the end pieces 3, 8, a shoulder which is adjoined
in each case by a widened region 26, 27 which surrounds the end
pieces 3, 8 at the circumference and is sealed with respect to
them, for example by soldering. The coolant inlet connecter 6 and
the coolant outlet connector 7 are arranged on opposite sides 2a,
2c of the housing casing 2 and each lead into the housing casing 2
via a distributor chamber 28 or a collector chamber 29. This
ensures that the coolant is distributed over the entire width. The
sectional illustration shows the flat pipes 9 from their
longitudinal or lateral side and thus also the corrugated piece of
sheet metal 10 with longitudinal ducts 10a. The corrugated piece of
sheet metal 10 has, as already mentioned, oblique indented edges
10b, 10c resulting in inflow and outflow regions 30, 31 in which
the transverse flow of the coolant from the inlet connector 6 and
in the direction of the outlet connector 7 is possible. Such inflow
regions 30 and outflow regions 31 are each located between adjacent
flat pipes 9. The coolant is diverted approximately at a right
angle directly downstream of the inflow region 30 and flows through
the heat exchanger 25 in the longitudinal direction, characterized
by the arrow P. The refrigerant flows through the heat exchanger
25, as. described above with respect to figs 1b and 1c. The
refrigerant and coolant are thus essentially guided in a parallel
flow mode and counter flow mode (apart from the diversions).
[0034] FIG. 2a shows a variant 32 of the heat exchanger 25 from
FIG. 2: the guidance of the refrigerant is changed to such an
extent that the refrigerant inlet pipe 4' is located at the end
piece 3' and the refrigerant outlet pipe 5' is located at the end
piece 8'. This means that the refrigerant essentially has a single
flow, i.e. is guided in a direction through the heat exchanger 32,
while the coolant is guided in the opposite direction,
corresponding to the arrow P. The refrigerant can however also be
guided in a three flow, five flow or multiple flow (uneven
numbered) configuration through the heat exchanger. This results
essentially in a counter flow between the refrigerant and
coolant.
[0035] FIG. 3 shows a further exemplary embodiment of a heat
exchanger 33 in which a corrugated piece of sheet metal 34 which.
is cut to size at right angles is provided with a longitudinal duct
34a. The coolant inlet connecter 6 and the coolant outlet connector
7 are arranged on the same side 2a of the housing casing. An
approximately right-angled inflow region 35 is produced in the
region of the inlet connector 6 between the end piece 8 and
corrugated piece of sheet metal 34, and a corresponding outflow
region 36 is produced in the region of the outlet connecter 7. Here
too, a cross flow of the coolant is therefore possible, while
otherwise there is a flow through the heat exchanger 33 in the
longitudinal direction corresponding to the arrow P. The regions 34
and 36 can also be provided with corrugated pieces of sheet metal
or other turbulence generators. The guidance of the refrigerant
flow corresponds to that in FIG. 2, i.e. the refrigerant inlet pipe
4 and refrigerant outlet pipe 5 are arranged on the same end piece
3.
[0036] FIG. 3a shows a variant 37 of the heat exchanger 33
according to FIG. 3. The only difference with respect to the heat
exchanger 33 is the guidance of the refrigerant which corresponds
to that in FIG. 2a, i.e. the refrigerant inlet pipe 4' is attached
to the end piece 3', and the refrigerant outlet pipe 5' is attached
to the end piece 8'. This produces essentially a counter flow
between the refrigerant and coolant which flows in the longitudinal
direction corresponding to the arrow P.
[0037] FIG. 4 shows a further exemplary embodiment of a heat
exchanger 38 in which the guidance of the refrigerant is analogous
to the exemplary embodiments in FIGS. 2 and 3, i.e. a block 11
according to fig. 1b is used. The coolant inlet connector 6 and the
coolant outlet connecter 7 are located directly opposite one
another at the same level, i.e. they are both arranged in the
region of the end piece 3. A dividing wall 39, which delimits an
inflow region 40 on the side of the inlet connector 6 and an
outflow region 41 on the side of the outlet connector 7 is arranged
centrally between the inlet connector 6 and outlet connector 7. The
dividing wall 39 is arranged in each case between adjacent flat
pipes. A corrugated piece of sheet metal 42 with longitudinal ducts
42a adjoins the dividing wall 39 and extends as far as a diverter
region 43. The corrugated piece of sheet metal 42 has, as stated
above, an approximately trapezoidal section which is soldered in
each case to the adjacent flat pipes. As a result, discrete
longitudinal ducts 42a are formed, i.e. a cross flow between the
longitudinal ducts 42a is not possible. The coolant thus flows out
of the inflow region 40 firstly in the upper half of the heat
exchanger 38, following the arrow P1, into the diverter region 43
where it is diverted by 180.degree., i.e. in the opposite
direction, corresponding to the arrow P2. It then flows in the
lower half of the heat exchanger 38, following the arrow P3, and
back into the outflow region 41 and leaves the heat exchanger 38
there via the outlet connector 7.
[0038] The coolant thus travels through twice the distance in the
heat exchanger 38 compared to the previous exemplary embodiments so
that an intensive exchange of heat with the refrigerant takes
place. Likewise, a four flow or multiple (even numbered) flow
through the heat exchanger by the refrigerant is possible.
[0039] Here too, the corrugated pieces of sheet metal are provided
with slots and/or offsets so that exchange is possible between the
longitudinal guiding ducts for the coolant, and thus more
homogenous distribution and/or turbulences of the coolant and
ultimately an increased transfer of heat are possible. Pieces of
sheet metal with transversely extending coolant ducts can also be
used here to make the surface larger and thus increase the
efficiency of the heat exchanger.
[0040] FIG. 5 shows a cross section through a heat exchanger 44
which corresponds to the heat exchanger in FIG. 2, the end piece 3
being omitted. The view here is therefore directly onto the end
sides of the flat pipes 9, which are embodied as extruded
multichamber pipes with circular flow ducts 43. In each case a
corrugated piece of sheet metal 10 with a trapezoidal section is
arranged between adjacent flat pipes 9 and soldered to the flat
pipes 9. As a result, discrete longitudinal ducts 10a are formed
for the coolant. These pieces of sheet metal can also be provided
with slots and/or offsets in order to permit exchange between the
longitudinal ducts for the coolant and thus permit more homogenous
distribution and/or turbulences of the coolant.
[0041] If there is no provision for the coolant to be diverted, as
illustrated in FIG. 4, but only a single flow is provided, no
discrete longitudinal ducts 10a are necessary and instead a
transverse connection may be desired between the individual
longitudinal ducts. This can be implemented by what are referred to
as turbulence baffles (not illustrated) in which the trapezoidal
sectional is arranged in a respectively offset fashion downstream
of specific longitudinal sections so that new leading edges and
thus increased eddying is produced. The housing casing 2 is
embodied here as a U-shaped frame with a shoulder and a widened
portion 26 into which the end piece (not illustrated) is inserted.
The heat exchanger block 11 (cf. FIGS 1a, 1b) can thus be easily
inserted into the housing 2 and closed off by a lid (not
illustrated). The distributor chamber 28 which adjoins the inlet
connector 6 extends over the entire height of the housing wall 2c,
and in an analogous fashion the collector chamber 29 has
approximately the height of the side wall 2a on the side of the
outlet connector 7. As a result, the coolant can be distributed
between all flat pipes 9, and likewise the coolant can be collected
in the collector chamber 29 on the outlet side.
[0042] FIG. 6 shows a longitudinal section through a flat pipe 9
which is held with its flat pipe end 9a in the end piece 3 and its
flat pipe end 9b in the end piece 8. The two end pieces 3, 8 are
embodied as illustrated in fig. 1b. This design for the flat pipes
9 with the end pieces 3, 8 made of individual plates is
particularly suitable for high pressures such as occur in the
CO.sub.2 refrigerant process.
[0043] FIG. 7 shows a further exemplary embodiment of a heat
exchanger 46 with a modified coolant guiding means. A refrigerant
block 47 is in principle of similar design to the block 11
according to fig. 1b, i.e. it has a first end piece 48 with a
refrigerant inlet pipe 49 and refrigerant outlet pipe 50 as well as
a second end piece 51 in which the refrigerant is diverted. The end
piece 48 has a laterally lengthened base plate 52 to which a
coolant inlet duct 53 is attached. The end piece 51 also has a
lengthened base plate 54 to which a coolant outlet duct 55 is
attached. A housing casing 56 surrounds the block 47 and forms in
each case a coolant inlet chamber 57 and a coolant outlet chamber
58, which are each embodied in the form of a wedge. The coolant
enters the inlet chamber 57 through the inlet duct 53 and passes
from there between the gaps between the flat pipes of the block 47,
flows through them in the transverse direction corresponding to the
arrows P4, passes into the outlet chamber 58 and from there into
the coolant outlet duct 55. This design permits a single transverse
flow through the block 47. In order to increase the transfer of
heat it is possible (not illustrated here) for corrugated pieces of
sheet metal or turbulence inserts to be arranged in turn between
the individual flat pipes, said corrugated pieces of sheet metal or
turbulence inserts causing the coolant to be guided in the
direction of the arrow P4 and generate turbulence.
[0044] FIG. 8 shows a further exemplary embodiment of a heat
exchanger 59 with a coolant flow which is also guided transversely
but is only illustrated schematically. This is shown by means of a
longitudinal section through a flat pipe 9, as illustrated in. FIG.
6. A refrigerant block 60 is divided into three flow regions I, II,
III by two dividing walls 61, 62. The regions I, II are connected
to one another by a diverter chamber 63, and the regions II, III
are connected to one another on the opposite side by a further
diverter chamber 64. The coolant enters the region I of the block
60 via an inlet connector 65 (also illustrated only schematically),
is diverted in the diverter chamber 63 and then flows through the
region II into the diverter chamber 64, is diverted there once more
and finally passes into the region III which it leaves via an
outlet connector 66. The inlet and outlet connectors 55, 56 and
diverter chambers 63, 64 are part of a housing casing (not
illustrated in more detail) which surrounds the block 60. This flow
guidance, corresponding to the arrows P5, P6, P7 causes the coolant
to be guided transversely across the block 60 three times, thus
producing a cross flow between the refrigerant and coolant. Of
course, only a single diversion with one dividing wall and one
diverter box as well as triple diversion or multiple diversion of
the coolant are also possible.
[0045] The exemplary embodiments of refrigerant/coolant heat
exchangers described above are preferably soldered, which applies
in particular to the block through which CO.sub.2 flows. In
contrast, because of the considerably lower pressure of the
coolant, the housing casing could also be connected to the block or
its end pieces using alternative connection techniques, for example
by bonding or by means of rubber seals. At the same time, other
materials such as, for example, plastic, are also possible for the
housing casing.
[0046] The invention has been explained using the example of a
refrigerant/coolant heat exchanger but it also includes other heat
exchangers. For example, oil and/or air could flow through a heat
exchanger according to the invention and exchange heat with one
another or with other media.
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