U.S. patent application number 13/934514 was filed with the patent office on 2014-06-12 for plate for heat exchanger, heat exchanger and air cooler comprising a heat exchanger.
The applicant listed for this patent is AIREC AB. Invention is credited to Marcello Masgrau, Sven Persson.
Application Number | 20140158328 13/934514 |
Document ID | / |
Family ID | 50879686 |
Filed Date | 2014-06-12 |
United States Patent
Application |
20140158328 |
Kind Code |
A1 |
Persson; Sven ; et
al. |
June 12, 2014 |
PLATE FOR HEAT EXCHANGER, HEAT EXCHANGER AND AIR COOLER COMPRISING
A HEAT EXCHANGER
Abstract
A plate for a heat exchanger for heat exchange between a first
and a second medium has a first side and an opposing second side.
The first side is configured with at least one heat transferring
elevation and with at least one heat transfer surface surrounding
the elevation. Dimples are provided at either or both of the heat
transferring elevation and the heat transfer surface to permit
provision of a through-flow duct for the first medium. The second
side is configured with at least one heat transferring depression
corresponding to the elevation. The depression is configured to
define a part of a through-flow duct for the second medium. The
second side has at least one bonding surface corresponding to the
heat transfer surface and surrounding the depression. A heat
exchanger includes a stack of the above-mentioned plates and an air
cooler includes such a heat exchanger.
Inventors: |
Persson; Sven; (Limhamn,
SE) ; Masgrau; Marcello; (Malmo, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AIREC AB |
Malmo |
|
SE |
|
|
Family ID: |
50879686 |
Appl. No.: |
13/934514 |
Filed: |
July 3, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13541788 |
Jul 5, 2012 |
|
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|
13934514 |
|
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Current U.S.
Class: |
165/109.1 |
Current CPC
Class: |
F28F 3/042 20130101;
F28F 9/001 20130101; F28D 9/0056 20130101; F28D 1/0341 20130101;
F28F 3/046 20130101; F28F 3/044 20130101 |
Class at
Publication: |
165/109.1 |
International
Class: |
F28F 13/12 20060101
F28F013/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 5, 2012 |
EP |
12175135.8 |
Claims
1. Plate for a heat exchanger for heat exchange between a first and
a second medium, wherein the plate (1) has a first side (A) and an
opposing second side (B), wherein the first side (A) of said plate
(1) is configured with at least one heat transferring elevation (2)
and with at least one heat transfer surface (4) surrounding said
elevation, wherein dimples (5; 7) are provided at either or both of
the heat transferring elevation (2) and the heat transfer surface
(4) to permit provision of a through-flow duct (X) for the first
medium, wherein the second side (B) of said plate (1) is configured
with at least one heat transferring depression (3) corresponding to
said elevation (2), said depression being configured to define a
part of a through-flow duct (Y) for the second medium, and with at
least one bonding surface (6) corresponding to said heat transfer
surface (4) and surrounding said depression, wherein the heat
transferring elevation (2) on the first side (A) of the plate (1)
has a first height (h1) corresponding to a depth of the heat
transferring depression (3) on the second side (B) of the plate and
a width (w) corresponding to a width of the heat transferring
depression (3), and wherein the heat transferring depression (3) on
the second side (B) of the plate (1) is provided with pressure
resisting dimples (8) with a height corresponding to said first
height (h1) of the heat transferring elevation (2) and to the depth
of said corresponding heat transferring depression.
2. Plate according to claim 1, wherein the dimples (5) provided on
the heat transfer surface (4) on the first side (A) of the plate
(1) has a second height (h2) which is larger than said first height
(h1), and/or wherein the dimples (7) provided on the heat
transferring elevation (2) on said first side (A) of the plate (1)
has a height (h2-h1) which together with the height (h1) of the
elevation is larger than said first height (h1).
3. Plate according to claim 1, wherein the width (w) of the heat
transferring elevation (2) and of the corresponding heat
transferring depression (3) is at least 5 times larger than said
first height (h1) of said heat transferring elevation and the depth
of said corresponding heat transferring depression.
4. Plate according to claim 1, wherein the heat transferring
elevation (2) on the first side (A) of the plate (1) and the
corresponding heat transferring depression (3) on the second side
(B) of the plate are configured with two or more straight, parallel
or substantially parallel portions.
5. Plate according to claim 1, wherein the pressure resisting
dimples (8) are elongated and arranged to extend obliquely across
the heat transferring depression (3) and spaced apart from each
other in the longitudinal direction of said heat transferring
depression.
6. Plate according to claim 1, wherein the heat transfer surface
(4) on the first side (A) of the plate (1) is provided with
reinforcing dimples (9).
7. Plate according to claim 2, wherein the plate (1) is configured
with first and second portholes (10 and 11) for the second medium,
each of said portholes (10, 11) being on said first side (A) of the
plate (1) configured with an edge (10a, 11a) which surrounds said
porthole, said edge forming part of said heat transferring
elevation (2) and having a height corresponding to said second
height (h2) of the dimples (5) and/or corresponding to the height
(h2-h1) of the dimples (7) provided on the heat transferring
elevation (2) together with the height (h1) of said heat
transferring elevation.
8. Heat exchanger for heat exchange between a first and a second
medium, wherein said heat exchanger comprises a stack of plates (1)
according to claim 1, and wherein said plates (1) are arranged such
that the first side (A) of each plate is abutting the first side
(A) of an adjacent plate (1) in the stack, thereby providing, by
means of the dimples (5; 7) on either or both of the heat transfer
surfaces (4) or the heat transferring elevations (2) on the first
sides (A) of two adjacent plates in the stack, the through-flow
duct (X) for the first medium between said first sides of said
plates, and such that the second side (B) of each plate (1) is
abutting the second side (B) of an adjacent plate (1) in the stack,
thereby defining, by means of the heat transferring depressions (3)
on the second sides (B) of two adjacent plates in the stack, at
least one through-flow duct (Y) for the second medium between said
second sides of said plates.
9. Heat exchanger according to claim B, wherein the first sides (A)
of two adjacent plates (1) in the stack are assembled at opposing
dimples (5; 7) on either or both of the heat transfer surfaces (4)
and the heat transferring elevations (2) on said first sides, and
assembled at opposing edges (10a, 11a) on said first sides
surrounding portholes (10, 11) for the second medium in the plates
by leak-free bonding of said edges to each other.
10. Heat exchanger according to claim 8, wherein the pressure
resisting dimples (8) in the heat transferring depressions (3) on
the second sides (B) of two adjacent plates (1) in the stack are
configured for engagement with each other when said second sides
(B) of said two adjacent plates (1) in the stack abut each
other.
11. Heat exchanger according to claim 10, wherein the second sides
(B) of two adjacent plates (1) in the stack are assembled by
leak-free bonding of opposing bonding surfaces (6) on said second
sides to each other and assembled at opposing dimples (8) in the
heat transferring depressions (3) on said second sides.
12. Heat exchanger according to claim 8, wherein straight, parallel
or substantially parallel portions of the heat transferring
depressions (3) on the second sides (B) of two adjacent plates (1)
defining the through-flow duct (Y) for the second medium extend in
a first direction (D1) of the plate, and wherein the through-flow
duct (X) for the first medium provided between the first sides (A)
of two adjacent plates (1) extends in a second direction (D2) of
the plate which is substantially perpendicular to said first
direction (D1).
13. Heat exchanger according to claim 8, wherein the stack of
plates (1) of the heat exchanger is located in a frame work (12)
with opposing plate elements (13 and 14).
14. Heat exchanger according to claim 13, wherein at least one of
the opposing plate elements (13, 14) is provided with pipe
connections (15 and 16) for the second medium.
15. Air cooler comprising a heat exchanger according to claim 8,
wherein the first medium is air and the second medium is a liquid.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 13/541,788, filed Jul. 5, 2012 and European
Appln. No. 12175135.8, filed Jul. 5, 2012, which are hereby
incorporated by reference in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to a plate for a heat
exchanger for heat exchange between a first and a second medium.
The plate has a first side and an opposing second side. The first
side of said plate is configured with at least one heat
transferring elevation and is also configured to permit provision
of a through-flow duct for the first medium. The second side of
said plate is configured with at least one heat transferring
depression corresponding with the elevation on said first side to
define a part of a through-flow duct for the second medium.
[0003] The present invention further relates to a heat exchanger,
wherein the heat exchanger comprises a stack of the above-mentioned
plates. The plates are arranged such that the first side of each
plate is abutting and assembled with the first side of an adjacent
plate in the stack, thereby defining the through-flow duct for the
first medium between said first sides of said plates. Consequently,
the plates are also arranged such that the second side of each
plate is abutting and assembled with the second side of an adjacent
plate in the stack, thereby defining at least one through-flow duct
for the second medium between said second sides of said plates.
[0004] The present invention also relates to an air cooler
comprising the above-mentioned heat exchanger.
BACKGROUND OF THE INVENTION
[0005] Heat exchangers are used in many different areas, e.g. in
the food processing industry, in buildings for use in heating and
cooling systems, in gas turbines, boilers and many more. Attempts
to improve the heat exchanging capacity of a heat exchanger is
always interesting and even small improvements are highly
appreciated.
SUMMARY OF THE INVENTION
[0006] An object of the present invention is to provide a plate for
a heat exchanger and a heat exchanger for improved primary as well
as secondary heat exchange.
[0007] The above and further objects are achieved by means of a
plate wherein the first side of said plate is configured not only
with at least one heat transferring elevation, but also with at
least one heat transfer surface which surrounds said elevation and
where dimples are provided at either or both of the heat transfer
surface and the heat transferring elevation to permit provision of
the through-flow duct for the first medium, and wherein the second
side of the plate is configured not only with at least one heat
transferring depression, but also with at least one bonding surface
which corresponds to said heat transfer surface and which surrounds
said depression.
[0008] Thus, the heat transferring elevation on the first side of
the plate defines a primary heat transfer area for the first medium
and the heat transfer surface surrounding said elevation a
secondary heat transfer area for the first medium and the heat
transferring depression on the second side of the plate defines a
primary heat transfer area for the second medium. Thereby, a plate
for a heat exchanger is provided, by means of which a larger heat
transfer area for said first medium, which is the medium having the
smallest coefficient of heat transmission, e.g. air in relation to
water, which shall flow at a smaller speed/pressure, is
defined.
[0009] By configuring the heat transferring elevation and the
corresponding heat transferring depression such that the width
thereof is many times larger than their height/depth and such that
they have an extension with two or more straight, parallel or
substantially parallel portions, the primary heat transfer areas
for the first and the second medium respectively, are enlarged.
[0010] The above and other objects are achieved also by means of a
heat exchanger wherein said plates are not only arranged such that
the first side of each plate is abutting the first side of an
adjacent plate in the stack, but also such that said plates thereby
provide, by means of the dimples on either or both of the heat
transfer surfaces and the heat transferring elevations on the first
sides of two adjacent plates in the stack, the through-flow duct
for the first medium between said first sides of said plates, and
said plates are not only arranged such that the second side of each
plate is abutting the second side of an adjacent plate in the
stack, but also such that said plates thereby define, by means of
the heat transferring depressions on the second sides of two
adjacent plates in the stack, at least one through-flow duct for
the second medium between said second sides of said plates.
[0011] Thus, since the through-flow duct for the first medium is
provided by means of opposing dimples on the heat transfer surfaces
on the first sides of two adjacent plates in the stack, and since
the through-flow duct for the second medium is defined by opposing
heat transferring depressions on the second sides of two adjacent
plates in the stack, a heat exchanger is provided, by means of
which a larger volume of the through-flow duct for said first
medium is defined.
[0012] Since the through-flow duct for the second medium is defined
by opposing heat transferring depressions having a width which is
many times larger than their depth, i.e. the heat transferring
surface of the through-flow duct is large in relation to its
volume, and having an extension with two or more straight, parallel
or substantially parallel portions, the primary heat transferring
capacity of the heat exchanger is improved.
[0013] As defined, a heat exchanger is provided, the total
heat-exchanging capacity of which is improved and the costs for its
manufacture are reduced.
[0014] As defined, the heat exchanger may be used to provide e.g.
an improved air cooler, i.e. one medium is air and the other a
liquid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The present invention will be further described below with
reference to the accompanying drawings, in which
[0016] FIG. 1 is a schematic perspective view of an embodiment of a
plate according to the invention;
[0017] FIG. 2 is another perspective view of the plate of FIG.
1;
[0018] FIG. 3 is a schematic plan view of one side of the
embodiment of a plate according to FIGS. 1 and 2;
[0019] FIG. 4 is schematic plan view of the opposite side of the
plate of FIG. 3;
[0020] FIG. 5 is a schematic side view of a part of the plate of
FIGS. 1-4;
[0021] FIG. 6 is a schematic perspective view of two plates
according to FIGS. 1-4 ready for assembly;
[0022] FIG. 7 is a schematic side view of the two plates of FIG. 6
after assembly;
[0023] FIG. 8 is a schematic view of four plates according to FIGS.
1-4 after assembly;
[0024] FIG. 9a is a schematic perspective view of a heat exchanger
according to the invention, comprising a stack of plates as
illustrated in FIGS. 1-8;
[0025] FIG. 9b illustrates schematically how the heat exchanger of
FIG. 9a is located in a refrigerated display case and how the first
and second media thereby flow through the heat exchanger;
[0026] FIG. 10 is a schematic perspective view of a second
embodiment of a plate according to the invention, and
[0027] FIG. 11 is a schematic perspective view of a part of a third
embodiment of a plate according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0028] As already stated, the present invention relates to a plate
for a heat exchanger for heat exchange between a first and a second
medium.
[0029] The first and second medium referred to for heat exchange
may be the same, e.g. gas/gas (such as air) or liquid/liquid (such
as water). The first and second medium referred to may also be two
different media, e.g. gas/liquid or two different gases or
liquids.
[0030] As illustrated in particularly FIGS. 1-6, the plate 1 has a
first side A and a second side B. The first side A of the plate 1
is configured with at least one heat transferring elevation 2. The
first side A of the plate 1 is also configured to permit provision
of a through-flow duct X (see FIG. 8) for the first medium. The
second side B of the plate 1 is configured with at least one heat
transferring depression 3 substantially corresponding to the
elevation 2 on the first side A, i.e. the depression defines the
elevation 2 on said first side of the plate, with substantially the
same length and width and with a depth corresponding to the height
of said elevation. The heat transferring depression 3 is configured
to define a part of a through-flow duct Y (see FIGS. 7 and 8) for
the second medium. The heat transferring elevation 2 and the heat
transferring depression 3 are brought to correspond to each other
by subjecting the plate 1 to e.g. a stamping or punching process.
If desired, more than one elevation 2 and corresponding depression
3 may be provided on the first side A and the second side B
respectively, of the plate 1.
[0031] As is apparent from particularly FIGS. 1, 3 and 6, the first
side A of the plate 1 is further configured with at least one heat
transfer surface 4 which surrounds the heat transferring elevation
2. The heat transfer surface 4 is provided with dimples 5 which
permit provision of the through-flow duct X for the first medium.
The elevation 2 on the first side A of the plate 1 defines a
primary heat transfer area for the first medium and the heat
transfer surface 4 surrounding said elevation a secondary heat
transfer area for the first medium. These primary and secondary
heat transfer areas, i.e. the area of said elevation 2 and the area
of said heat transfer surface 4 are together substantially equal to
the entire area of the first side A of the plate 1.
Correspondingly, as is apparent from FIGS. 2, 4 and 6, the second
side B of the plate 1 is further configured with at least one
bonding surface 6 which corresponds to, i.e. has the same extension
as the heat transfer surface 4 on the first side A, and which
accordingly surrounds the heat transferring depression 3. The
depression 3 defines a primary heat transfer area for the second
medium. This primary heat transfer area, i.e. the area of the
depression 3, is substantially equal to the entire area of said
second side of the plate minus the area of the bonding surface 6.
From the above, it is apparent that the combined heat transfer
areas for the first medium are larger than the heat transfer area
for the second medium. This feature is advantageous when the first
medium has a smaller coefficient of heat transmission, such as air
in relation to water, and shall flow at a smaller speed/pressure
then the second medium in order to provide for optimum heat
transfer. A heat exchanger comprising plates constructed as
described above, will have an improved heat-exchanging
capacity.
[0032] Thus, a primary heat transfer area as defined above is
provided by a surface on a member of the plate which is in direct
contact with one medium and where the opposite surface on said
member is in direct contact with the other medium, and a secondary
heat transfer area is provided by a surface on a member of the
plate which is in direct contact with one medium and where the
opposite surface on said member is not in direct contact with the
other medium.
[0033] To permit provision of the through-flow duct X for the first
medium, the heat transferring elevation 2 on the first side A of
the plate 1 is configured with a first height h1 and the dimples 5
on the heat transfer surface 4 on said first side has a second
height h2 which is larger than said first height (see particularly
FIG. 5). Thereby, the dimples 5 protrude up above the elevation 2.
The heat transferring depression 3 on the second side B of the
plate 1, corresponding to the elevation 2, is consequently
configured with a depth corresponding substantially to said first
height h1. The heat transferring elevation 2 on the first side A of
the plate 1 is in the illustrated embodiment of the plate provided
with additional dimples 7 to permit provision of the through-flow
duct X for the first medium. For this purpose, these additional
dimples 7 have a height which together with the (first) height h1
of the elevation 2 is larger than said first height. In the
illustrated embodiments, the height of the dimples 7 and the height
h1 of the elevation 2 corresponds substantially to said second
height h2, i.e. to the height of the dimples 5 on the heat transfer
surface 4. Thus, the height of the dimples 7 is h2 minus h1. In the
illustrated embodiment of a plate according to FIGS. 1-8, the heat
transferring elevation 2 on the first side A of the plate has a
first height h1 from the heat transfer surface 4 of about 0.5-1
millimeter and the corresponding heat transferring depression 3 on
the second side B of the plate a depth from the bonding surface 6
corresponding substantially to said first height, and the dimples 5
on the heat transfer surface of side A has a second height h2 from
said heat transfer surface of about 2-2.5 millimeters. These
heights however, may vary in view of the intended application and
size of the heat exchanger in which the plate shall be used. The
dimples 5 and 7 on the first side A of the plate 1 can be made in
any suitable manner, e.g. by a similar stamping or punching process
as the heat transferring elevation 2/depression 3 such that
corresponding depressions are formed in the bonding surface 6 and
in the depression respectively, on the second side B of the plate,
and simultaneously with said elevation/depression. The size, shape
and number of the dimples 5, 7 may also vary in view of the
intended application and size of the heat exchanger and so may the
patterns in which they are arranged. The larger the plate 1, the
more dimples 5, 7 providing distances and supporting points to
permit provision of the through-flow duct X for the first medium
will be required. It should be emphasized however, that according
to the invention, it is possible to permit provision of the
through-flow duct X for the first medium also by means of the
dimples 5 on the heat transfer surface 4 only or by means of the
dimples 7 on the heat transferring elevation 2 only. In the
illustrated embodiment, the dimples 5, 7 are substantially
round.
[0034] The dimples 5, 7 on the first side A of the plate 1 are
suitable for abutment against and assembly in any suitable manner
with corresponding dimples on the first side of another plate such
that said dimples thereby permit provision of the through-flow duct
X for the first medium (FIG. 8). The bonding surface 6 on the
second side B of the plate 1 is in the same way suitable for
abutment against and leak-free assembly in any suitable manner with
a corresponding bonding surface on the second side of another plate
such that the heat transferring depressions 3 on said plates
thereby define the through-flow duct Y for the second medium (FIGS.
7 and 8). However, the dimples 5, 7 on the first side A of the
plate 1 may also be located such that abutment against and assembly
with corresponding dimples on the first side of another plate is
avoided, i.e. the dimples on the two plates are in some way located
offset relative to each other. Similarly, it is also possible to
locate the heat transferring depression 3 on the second side B of
the plate 1 such that it is offset relative to a heat transferring
depression on the second side of another plate.
[0035] The heat transferring depression 3 defining a part of the
through-flow duct Y for the second medium on the second side B of
the plate and the corresponding heat transferring elevation 2 on
the first side A of the plate, may vary in shape, size, number and
location. Accordingly, the depression 3 and the corresponding
elevation 2 may e.g. be U-shaped, comprising two straight, parallel
or substantially parallel portions. However, in order to prolong
the time for heat exchange between the first and second media, the
depression 3 and the corresponding elevation 2 may alternatively
have a substantially sinusoidal shape with three or more straight,
parallel or substantially parallel portions, i.e. an uneven (see
FIG. 10) or (as in FIGS. 1-8) an even number of straight, parallel
or substantially parallel portions. In order to maximize the heat
exchange between the first and second media, it is advantageous if
the heat transfer area of the depression 3 and of the corresponding
elevation 2 is as large as possible relative to the volume of the
through-flow duct Y for the second medium. Therefore, the width w
of the depression 3 and of the corresponding elevation 2 is in the
illustrated embodiments substantially larger than the depth of said
depression and the corresponding height of the elevation, e.g. at
least about 5 times larger and preferably, as in the illustrated
embodiments, about 50-70 times larger. Accordingly, in the
illustrated embodiments with a heat transferring elevation 2 with a
first height h1 of about 0.5-1 mm and a corresponding heat
transferring depression 3 with a depth corresponding to said first
height, the width w of the elevation and the corresponding
depression will be at least about 2.5 mm and preferably about 25-70
mm. The width w of the depression 3 and the corresponding elevation
2 may be constant or may also vary along its length, as illustrated
in particularly FIGS. 1-4, 6 and 10. In FIGS. 1-4, 6 and 10 it is
shown how the width w of the straight parallel portions first
decrease and then increase back to the original width. Thus, if the
first height h1 and the corresponding depth is about 0.5 mm, the
width w of the heat transferring elevation 2 and the corresponding
heat transferring depression 3 may decrease from about 35 mm to
about 25 mm and then again increase to about 35 mm. At the portions
of the depression 3 and the corresponding elevation 2 connecting
the straight parallel portions thereof, the width w is much smaller
than at said straight portions, in the illustrated embodiments
about 20 times larger than the first height h1 and the depth
corresponding thereto. Also, the depression 3 and the corresponding
elevation 2 may, as in the illustrated embodiments with a
rectangular plate 1, be provided with the straight parallel
portions thereof running in a direction transverse to the
longitudinal direction of the plate or substantially transverse
thereto. If desired, said straight parallel portions may
alternatively run in the longitudinal direction of the plate 1 or
in any other desired direction.
[0036] To prevent compression of the through-flow duct Y for the
second medium, the heat transferring depression 3 on the second
side B of the plate 1 is configured with pressure resisting dimples
8. These pressure resisting dimples 8 have in the illustrated
embodiment a height corresponding substantially to said first
height h1, i.e. the height of the heat transferring elevation 2 and
consequently, the depth of the corresponding heat transferring
depression, such that these dimples 8 end substantially at the same
level from which the depression protrude. By ending at the same
level as the bonding surface 6 on the second side B of the plate 1,
said dimples 8 may engage the corresponding dimples on the second
side of another plate to prevent compression of the through-flow
duct Y for the second medium, and may also contribute to safe and
effective assembly of said second side with the second side of said
other plate by bonding said dimples to each other in a suitable
manner. The dimples 8 also promote the flow of the second medium
through the through-flow duct Y therefore, by creating turbulence
in said flow such that the heat exchanging effect is improved.
However, if desired, the height of the dimples 8 may be less than
said first height h1. In the illustrated embodiment, the dimples 8
have a round as well as an elongated shape. Some of the elongated
dimples are also curved. The dimples 8 may also be arranged in any
suitable pattern for optimizing the heat exchanging effect.
[0037] In one embodiment schematically illustrated in FIG. 11, the
pressure resisting dimples 8 are elongated and extend obliquely
across the heat transferring depression 3, preferably also parallel
to each other, and, when the second sides B of two plates 1 are
brought together, obliquely across the through-flow duct Y for the
second medium, preferably across the entire width of the heat
transferring depression/through-flow duct, and said elongated
dimples are spaced apart from each other in the longitudinal
direction of said heat transferring depression/through-flow duct.
The heat transferring elevation 2/depression 3 may branch-off at
certain desired points between the elongated dimples 8 and then
immediately unite again in order to provide space for dimples 5
extending from the heat transfer surface 4 instead of dimples 7
extending from the heat transferring elevation 2, such that only
dimples 5 with the second height h2 are found on the first side A
of the plate 1. The elongated dimples 8 preferably have a
substantially triangular cross-section, but may also have any other
desired cross-section, e.g. a substantially frustoconical
cross-section as illustrated in FIG. 11. The dimples 8 are arranged
such that when the second sides B of two plates 1 are brought
together, abutting each other, said dimples run crosswise,
preferably at right angles, relative to each other, providing a
plurality of points for engagement and possible assembly of said
dimples to each other.
[0038] On the opposite first side A of the plate 1, the heat
transferring elevation 2 is consequently interrupted by the
elongated dimples 8 in the heat transferring depression 3 on the
second side B of the plate, said dimples thereby defining
correspondingly configured "grooves" 8a in the heat transferring
elevation which form part of the through-flow duct X for the first
medium. Accordingly, these "grooves" 8a extend obliquely across the
heat transferring elevation 2, preferably from one side thereof to
the other, and spaced apart from each other, defining between them
"rib-like" portions 2a of the heat transferring elevation. As
indicated above, some of these "rib-like" portions 2a are
interrupted, preferably in the centre of their longitudinal
extension, to provide space for the dimples 5. As is apparent from
FIG. 11, this embodiment also gives the impression that the heat
transferring elevation on the first side A of the plate 1 rather
can be regarded as comprising a plurality of separate elongated,
parallel and obliquely extending heat transferring elevations with
portions of the heat transfer surface 4 (defined by the "grooves"
8a) running therebetween.
[0039] The embodiment described above and schematically illustrated
in FIG. 11 provides for particularly a strong through-flow duct Y
for the second medium, but it is obvious from the above that if
desired, the elongated dimples 8 may also extend in non-parallel
directions relative to each other and there may be provided dimples
7 which extend from the "rib-like" portions 2a of the heat
transferring elevation 2.
[0040] To promote the flow of the first medium through the
through-flow duct X therefor by reinforcing the through-flow duct
and prevent it from collapsing, the heat transfer surface 4 on the
first side A of the plate 1 is in a similar way provided with
reinforcing dimples 9. These reinforcing dimples 9 have in the
illustrated embodiments a height corresponding substantially to
said first height h1, i.e. the height of the heat transferring
elevation 2, such that the dimples end substantially at the same
level as the elevation 2. However, it is desired that the height of
the dimples 9 is less than said first height h1 and preferably as
small as possible in order to minimize the pressure drop in the
flow of the first medium in the through-flow duct X and yet
maintain the reinforcing capacity of the dimples. The height of the
dimples 9 can also be larger than said first height as long as it
does not exceed the (second) height h2 of the dimples 5. In the
illustrated embodiments, the dimples 9 have an elongated shape. The
dimples 9 may also be arranged in any suitable pattern for
optimizing the heat exchanging effect.
[0041] As with the heat transferring elevation 2/depression 3 and
the above-mentioned dimples 5, 7 permitting provision of the
through-flow duct X for the first medium, the dimples 8 and 9 can
be made e.g. by a stamping or punching process or in any other
suitable manner, and simultaneously with said elevation/depression
and said above-mentioned dimples 5, 7. Corresponding depressions
are thereby formed on the respective opposite side A, B of the
plate 1, i.e. in the elevation 2 on side A and in the bonding
surface 6 on side B respectively.
[0042] As stated above, the plate 1 may be rectangular in shape,
with two opposing long sides 1a and 1b and two opposing short sides
1c and 1d, and with first and second portholes 10 and 11 for the
second medium close to one of or both long sides and/or close to
one of or both short sides. The location of the portholes 10, 11 is
depending on the shape of the plate 1 as well as on the shape and
location of the heat transferring elevation 2 and the corresponding
heat transferring depression 3 on the plate. In the illustrated
embodiment of a rectangular plate 1 with an elevation 2 and a
corresponding depression 3 which comprises an even number of
straight parallel portions, each of the portholes 10, 11 is located
close to the same long side 1a and one of the short sides 1c, 1d,
in the corner defined by said long side and the respective short
side (see FIGS. 1-4). With an elevation 2 and a corresponding
depression 3 which comprises an uneven number of straight parallel
portions, each of the portholes 10, 11 is e.g. located close to one
of the long sides 1a, 1b and one of the short sides 1c, 1d, in the
corner defined by the respective long side and the respective short
side, i.e. diagonally opposite each other on the plate 1 (see FIG.
10). Each of said portholes 10, 11 is on said first side A of the
plate configured with an edge 10a and 11a respectively, which
surrounds said porthole. Each edge 10a, 11a forms a part of the
elevation 2 and has in the illustrated embodiment a height
corresponding to the second height h2, i.e. to the height of the
dimples 5 and to the combined height of the elevation 2 (h1) and
the dimples 7 (h2-h1) respectively, and may have the same function
as said dimples, i.e. to permit provision of the through-flow duct
X for the first medium, as well as to prevent leakage of the second
medium into the through-flow duct X for the first medium. The plate
1 may alternatively have a square shape, with four equally long
sides, or any other suitable four-sided, triangular, multi-sided,
round, rhombic, elliptic or other shape for the intended
application or use.
[0043] In the illustrated embodiment according to at least FIGS.
1-8, where the intended use for the plate 1 is in a heat exchanger
for a refrigerated display case, the plate 1 may have a length of
about 270 millimeters and a width of about 150 millimeters.
However, the plate 1 may have any other size optimized for its
intended application. Accordingly, the length of the plate 1 may
e.g. exceed 1 meter and the width thereof may exceed 0.5 meter. The
size of the plate 1 may also be smaller than the plate in the
illustrated embodiment and what is regarded as the width of the
plate may be larger than what is regarded as the length thereof,
based e.g. on how the plate is located in the heat exchanger and/or
how the through-flow ducts X, Y for the first and second media are
oriented.
[0044] As mentioned above, the present invention also relates to a
heat exchanger for heat exchange between a first and a second
medium, wherein said heat exchanger comprises a stack of plates 1
of the above-mentioned configuration. The stack of plates 1 may
thereby be located in a more or less open frame work 12 as
illustrated in FIG. 9a with opposing plate elements 13 and 14,
wherein at least one of the opposing plate elements (in FIG. 9a
plate element 13) is provided with pipe connections 15 and 16 for
the second medium, and with a top panel 17 and a partially open
bottom panel 18. The stack of plates 1 which may be located in the
illustrated framework 12 may comprise 360 plates, having a total
height of about 900 millimeters if each plate has a total height of
about 2.5 millimeters. However, the number of plates 1 in the stack
thereof may vary and so may the size of the heat exchanger,
depending on its intended application or use.
[0045] If the heat exchanger is located in a refrigerated display
case as illustrated in FIG. 9b with the bottom panel 18 of the
frame work 12 facing downwards, the top panel 17 of the frame work
facing upwards and the opposing plate elements 13, 14 of the frame
work facing to the sides, the plates 1 in the stack thereof will
then in turn extend in substantially parallel vertical planes and
the first medium (e.g. air to be chilled) will flow substantially
horizontally into and through the heat exchanger. Thus, the first
medium may flow into the heat exchanger e.g. from the left side
thereof and then substantially horizontally to the right through
the heat exchanger and leave the heat exchanger at its right side
or, as is illustrated in FIG. 9b, from the right side of the heat
exchanger and then substantially horizontally, in a direction
(illustrated by an arrow D2 in FIG. 9b) to the left through the
heat exchanger and leave the heat exchanger at its left side. The
second medium (e.g. water for chilling the air) will flow into the
heat exchanger through one of the pipe connections 15, 16 of the
plate element 13 provided therewith, pass horizontally through the
heat exchanger along a substantially sinusoidal path, the straight
parallel or substantially parallel portions of which run in a
substantially vertical direction (illustrated by an arrow D1 in
FIG. 9b), and leave the heat exchanger through the other of said
pipe connections 16, 15 of said plate element. In the illustrated
embodiment according to FIG. 9b, the second medium flows into the
heat exchanger through the left pipe connection 15 of the plate
element 13 and leaves the heat exchanger through the right pipe
connection 16. Thus, according to FIG. 9b, the first medium flows
in a substantially horizontal direction through the heat exchanger
and the second medium in an opposite horizontal direction along a
substantially vertical and substantially sinusoidal path through
the heat exchanger, such that the first medium to be chilled meets
the second medium for chilling in a heat transferring or heat
exchanging manner when both media have the highest temperature and
such that said first medium is gradually chilled by the gradually
colder second medium. A multi-step counter flow is achieved, in
which the first medium to be chilled repeatedly is brought in
contact with the second medium for chilling which flows in the
opposite horizontal direction along a substantially vertical and
substantially sinusoidal path through the heat exchanger.
Condensate from the chilled first medium will leave the heat
exchanger at the bottom thereof, through the partially open bottom
panel 18. A drain (not shown) may be provided at the bottom of the
heat exchanger for collecting the condensate. Thus, the frame work
12 of the heat exchanger facilitates drainage of condensate from
the heat exchanger. Also, inspection, cleaning and maintenance of
the heat exchanger as shown, is facilitated by the illustrated
frame work 12 thereof.
[0046] As already indicated above, the plates 1 in the stack
thereof in the heat exchanger are arranged such that the first side
A of each plate is abutting the first side A of an adjacent plate
in the stack, thereby providing, by means of the dimples 5 on the
heat transfer surfaces 4 and/or by means of the dimples 7 on the
heat transferring elevations 2 on the first sides of two adjacent
plates in the stack, the through-flow duct X for the first medium
between said first sides of said plates. Furthermore, the plates 1
are arranged such that the second side B of each plate is abutting
the second side B of an adjacent plate in the stack, thereby
defining, by means of the heat transferring depressions 3 on the
second sides of two adjacent plates in the stack, at least one
through-flow duct Y for the second medium between said second sides
of said plates.
[0047] By e.g. configuring each plate 1 such that the dimples 5 on
the first side A of the plate have a second height h2 which is
larger than the depth (corresponding to the first height h1 of the
heat transferring elevation) of the heat transferring depression 3
on the second side B of the plate and such that the area of the
heat transferring elevation 2 and of the heat transfer surface 4 on
said first side of the plate is larger than the area of the heat
transferring depression on the second side of the plate, as
indicated above, the volume of the through-flow duct X for the
first medium can be made larger than the volume of the through-flow
duct Y for the second medium when the first sides A of two adjacent
plates 1 and the second sides B of two adjacent plates
respectively, are brought to abut each other. This may be true also
if the dimples and the elevations/depressions are offset. As
illustrated in FIGS. 7 and 8, the volume of the through-flow duct X
for said first medium relative to the volume of the through-flow
duct Y for said second medium is further increased when the
through-flow duct for the first medium is provided by means of
opposing dimples 5 on the heat transfer surfaces 4 and/or by means
of opposing dimples 7 on the elevations 2 on the first sides A of
two adjacent plates in the stack, and when the through-flow duct
for the second medium is defined by opposing depressions 3 on the
second sides B of two adjacent plates in the stack.
[0048] To provide for a safe and durable stack of plates 1, the
first sides A of two adjacent plates in the stack are assembled at
the dimples 5, offset or not, on the heat transfer surfaces 4 on
said first sides and the second sides B of two adjacent plates in
the stack are assembled at the bonding surfaces 6 on said second
sides. The first sides A of two adjacent plates 1 in the stack may
also or alternatively be assembled at the dimples 7 on the heat
transferring elevations 2 if such dimples are present. Thus, in
consequence of that the combined heat transfer areas on the first
side A of the plate 1 are larger than the heat transfer area on the
second side B of the plate, the total bonding area on said first
side of the plate is smaller than the bonding area on said second
side of the plate. Adjacent plates 1 may be assembled by means of
e.g. a brazing process or by means of another suitable assembling
method. Leak-free assembly is required at least of the opposing
bonding surfaces 6 on the second sides B of respectively two
adjacent plates 1 in the stack, and of the opposing edges 10a, 11a
of the portholes 10, 11 on the first sides A of respectively two
adjacent plates in the stack.
[0049] It is obvious from the above that the different heights of
the dimples 5 and of the heat transferring elevation 2/depression 3
will provide for a through-flow duct X for the first medium which
is configured with an alternating height, i.e. when said first
medium flows from left to right or from right to left in FIG. 8 and
from right to left as in FIG. 9b. This alternating height will
alter the speed/pressure of the first medium during the flow
thereof through said through-flow duct X. Thus, in the illustrated
embodiment according to at least FIGS. 1-8, the through-flow duct X
for the first medium is configured with a third height h3 between
the heat transferring elevations 2 on the first sides A of two
adjacent plates 1 and a fourth height h4, which is larger than said
third height, between the heat transfer surfaces 4, surrounding
said elevations, on said first sides of said two adjacent plates.
The fourth height h4 is thereby substantially equal to twice the
(second) height h2 of the dimples 5 on the heat transfer surface 4
on the first side A of each plate 1 and the third height h3 is
substantially equal to said fourth height minus twice the (first)
height h1 of the elevation 2 on the first side of each plate (see
particularly FIG. 8).
[0050] In the illustrated embodiment according to at least FIGS.
1-8, the through-flow duct Y for the second medium is configured
with a fifth height h5 which is substantially equal to twice the
depth (corresponding to the (first) height h1 of the heat
transferring elevation 2) of the heat transferring depression 3 on
the second side B of each plate 1 (see particularly FIG. 7).
[0051] The stack of plates 1 in the heat exchanger may comprise
plates of one type. This may be the case when e.g. the heat
transferring elevation 2 on the first side A of each plate and the
corresponding heat transferring depression 3 on the second side B
of each plate have a substantially sinusoidal shape with an even
number of straight, parallel or substantially parallel portions (as
in the embodiment of a plate according to FIGS. 1-8).
Alternatively, the stack of plates 1 may comprise plates of two
types. This may be the case when e.g. the elevation 2 on the first
side A of each plate and the corresponding depression 3 on the
second side B of each plate have a substantially sinusoidal shape
with an uneven number of straight, parallel or substantially
parallel portions (as in the embodiment of a plate according to
FIG. 10). Two types of plates 1 will also be required if e.g. the
dimples 5 and/or the heat transferring elevations 2/depressions 3
on two adjacent plates are offset relative to each other and if the
height of said elevation and/or said dimples on the first side A of
one plate differs from the height of said elevation and/or said
dimples on the first side A of another plate. The heights of the
dimples 5 and/or of the elevations 2/depressions 3 may vary widely,
but it is of course important in said latter embodiment with two
types of plates that at least the total height of opposing dimples
always is larger than the total height of opposing elevations for
providing the through-duct X for the first medium between the first
sides A of two adjacent plates.
[0052] The heat exchanger according to the present invention may be
of the cross-flow type, wherein the straight, substantially
parallel portions of the heat transferring depressions 3 on the
second sides B of two adjacent plates 1 defining the through-flow
duct Y for the second medium extend in a first direction D1 of the
plate, and wherein the through-flow duct X for the first medium
provided between the first sides A of two adjacent plates extends
in a second direction D2 of the plate which is substantially
perpendicular to said first direction. The heat exchanger outlined
above is, as indicated, primarily a heat exchanger of this type.
The heat exchanger according to the present invention may
alternatively be of another type than said cross-flow type.
[0053] By utilizing a heat exchanger as defined above, comprising,
inter alia, a stack of plates as defined above, it is in fact
possible to reduce the energy consumption for chilling by about 20%
when e.g. water is used to chill air from a refrigerated display
case. The primary reason for this positive result is that the
temperature of the chilling water must not be reduced as much as in
prior art constructions to provide for efficient chilling of the
air. This is in turn the result of the prolonged, more extensive
direct and indirect contact of the air with the water.
[0054] It will be evident to a skilled person that the plate and
the heat exchanger according to the present invention can be
modified and altered within the scope of the subsequent claims
without departing from the idea and purpose of the invention. Thus,
although the plate 1 is made preferably of aluminum, it can also be
made of any other suitable material. The stack of plates in the
heat exchanger can be located in a frame work which is more open as
in the illustrated embodiment according to FIG. 9a and the frame
work can also be made of any suitable material. Furthermore, it is
obvious that the heat exchanger in its intended application can be
located in any suitable position, i.e. horizontally as in the
illustrated embodiment or vertically or obliquely if that is
required or desired. A heat exchanger as defined is suitable for
use as an air cooler, since the first medium, the medium to be
chilled, may be air.
* * * * *