U.S. patent application number 15/306062 was filed with the patent office on 2017-02-16 for heat exchanger comprising a core of tubes.
This patent application is currently assigned to TITANX ENGINE COOLING HOLDING AB. The applicant listed for this patent is TITANX ENGINE COOLING HOLDING AB. Invention is credited to Anders Brorsson, Arnaud Contet, Fredrik Lomnitz.
Application Number | 20170045312 15/306062 |
Document ID | / |
Family ID | 54332856 |
Filed Date | 2017-02-16 |
United States Patent
Application |
20170045312 |
Kind Code |
A1 |
Contet; Arnaud ; et
al. |
February 16, 2017 |
HEAT EXCHANGER COMPRISING A CORE OF TUBES
Abstract
The invention concerns a heat exchanger (1) comprising an inlet
tank (2), having a fluid inlet (4),and an outlet tank (3), having a
fluid outlet (5),and a core (6) of tubes (7, 8) joining said inlet
tank (2) and said outlet tank (3) together and creating a plurality
of fluid flow paths (P1) from said inlet tank (2) to said outlet
tank (3), wherein said tubes (7, 8) belong to a primary and a
secondary group of tubes(7, 8). According to the invention said
inlet tank (2) and said outlet tank (3) have header plates(9, 10),
which form core interfaces and comprise throughout identical tube
insertion orifices for both the primary group of tubes (7) and the
secondary group of tubes (8).Further, the tubes being a member of
the primary group are base tubes (7)and the tubes being a member of
the secondary group are adaptation tubes (8), which differ from the
base tubes (7) and a reused to locally change properties of the
heat exchanger (1) in critical areas of the heat exchanger (1).
Inventors: |
Contet; Arnaud; (Solvesborg,
SE) ; Brorsson; Anders; (Solvesborg, SE) ;
Lomnitz; Fredrik; (Karlshamn, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TITANX ENGINE COOLING HOLDING AB |
Solvesborg |
|
SE |
|
|
Assignee: |
TITANX ENGINE COOLING HOLDING
AB
Solvesborg
SE
|
Family ID: |
54332856 |
Appl. No.: |
15/306062 |
Filed: |
April 20, 2015 |
PCT Filed: |
April 20, 2015 |
PCT NO: |
PCT/SE2015/050449 |
371 Date: |
October 21, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28F 1/40 20130101; F28F
13/08 20130101; Y02T 10/12 20130101; F28F 2001/027 20130101; F28D
2021/0082 20130101; F28F 13/12 20130101; F28F 13/06 20130101; F28F
2225/00 20130101; Y02T 10/146 20130101; F02B 29/0462 20130101; F28D
1/05366 20130101; F28F 2215/04 20130101 |
International
Class: |
F28F 13/12 20060101
F28F013/12; F28F 1/40 20060101 F28F001/40; F28D 1/053 20060101
F28D001/053 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 22, 2014 |
SE |
1450473-2 |
Claims
1. A heat exchanger comprising one inlet tank, having a fluid inlet
for a fluid, and one outlet tank, having a fluid outlet for said
fluid, and a core of tubes joining said one inlet tank and said one
outlet tank together and creating a plurality of fluid flow paths
for said fluid from said one inlet tank to said one outlet tank,
wherein said tubes belong to a primary and a secondary group of
tubes, wherein said one inlet tank comprises a first header plate,
which forms a core interface of said one inlet tank, wherein said
one outlet tank comprises a second header plate, which forms a core
interface of said one outlet tank, wherein said first and second
header plates comprise throughout identical tube insertion orifices
for both the primary group of tubes and the secondary group of
tubes, and wherein the tubes being a member of the primary group
are base tubes, and the tubes being a member of the secondary group
are adaptation tubes, which are designed differently than the base
tubes of the primary group and are used to locally change
properties of the heat exchanger in critical areas of the heat
exchanger.
2. The heat exchanger according to claim 1, wherein said secondary
group in order to prolong life of the heat exchanger comprises
adaptation tubes each providing an enhanced strength compared to a
basic strength provided by each one of said base tubes, wherein
said adaptation tubes are used in areas of the heat exchanger where
stress levels tend to be higher than a medium stress level of the
entire heat exchanger.
3. The heat exchanger according to claim 2, wherein said adaptation
tubes provide an enhanced strength by having a wall thickness
exceeding a wall thickness of the base tubes.
4. The heat exchanger according to claim 2, wherein said adaptation
tubes provide an enhanced strength by comprising stiffening inserts
arranged in tube openings.
5. The heat exchanger according to claim 2, wherein said adaptation
tubes provide an enhanced strength by comprising first turbulators
that are stiffer than second turbulators arranged in said base
tubes.
6. The heat exchanger according to claim 2, wherein said adaptation
tubes provide an enhanced strength by comprising internal
stiffening ribs.
7. The heat exchanger according to claim 2, wherein said adaptation
tubes provide an enhanced strength by comprising extra durable tube
seams created by all smooth tube walls.
8. The heat exchanger according to claim 2, wherein said heat
exchanger comprises a first row of tubes and a second row of tubes,
and wherein at least a plurality of the tubes of the first row
belong to the primary group of tubes and all tubes of the second
row belong to the secondary group of tubes.
9. The heat exchanger according to claim 1, wherein said secondary
group in order to improve efficiency of the heat exchanger
comprises adaptation tubes, each providing a first flow resistance
that is lower than a second flow resistance provided by each one of
said base tubes, wherein said adaptation tubes are arranged in
areas of the heat exchanger where fluid flow levels tend to be
lower than a medium fluid flow level of the entire heat
exchanger.
10. The heat exchanger according to claim 9, wherein said
adaptation tubes provide a lower flow resistance by comprising
first turbulators that cause a lower flow resistance than second
turbulators being arranged in said base tubes.
11. The heat exchanger according to claim 9, wherein said
adaptation tubes provide a lower flow resistance by having all
smooth walls, while said base tubes have dimpled walls.
12. The heat exchanger according to claim 9, wherein said heat
exchanger comprises a first row of tubes and a second row of tubes,
and wherein all tubes of the first row belong to the secondary
group of tubes and all tubes of the second row belong to the
primary group of tubes.
13. The heat exchanger according to claim 1, wherein said secondary
group comprises adaptation tubes, each providing a lower flow
resistance than a flow resistance provided by each one of said base
tubes, wherein said adaptation tubes are arranged in the heat
exchanger in an alternating pattern mixed with base tubes.
14. The heat exchanger according to claim 13, wherein said
adaptation tubes provide a lower flow resistance by comprising
first turbulators that cause a lower flow resistance than second
turbulators being arranged in said base tubes.
15. The heat exchanger according to claim 13, wherein said
adaptation tubes provide a lower flow resistance by having all
smooth walls, while said base tubes have dimpled walls.
16. The heat exchanger according to claim 13, wherein said
alternating pattern comprises a row of alternatingly a base tube
and an adaptation tube.
17. The heat exchanger according to claim 13, wherein said
alternating pattern comprises a row of alternatingly two base tubes
and an adaptation tube.
18. The heat exchanger according to claim 1, wherein said secondary
group of tubes is subdivided into at least two kinds of differently
designed tubes.
Description
TECHNICAL FIELD
[0001] The present invention concerns a heat exchanger comprising
an inlet tank, having a fluid inlet for a fluid, and an outlet
tank, having a fluid outlet for said fluid, and a core of tubes
joining said inlet tank and said outlet tank together and creating
a plurality of fluid flow paths for said fluid from said inlet tank
to said outlet tank, wherein said tubes belong to a primary and a
secondary group of tubes.
PRIOR ART
[0002] A heat exchanger according to the preamble is known from the
patent U.S. Pat. No. 4,791,982. The heat exchanger revealed in that
patent is a coolant radiator which has a core comprising tubes
belonging to a primary and a secondary group of tubes. There is a
difference in tube size between the two groups, which is used
mainly to improve flow distribution and hence efficiency especially
at low flow rates.
OBJECT OF THE INVENTION
[0003] A drawback of the prior art heat exchanger is that its
technical concept is rather limited when it comes to versatility.
Since it comprises use of differently sized tubes, it necessitates
use of header plates having tube insertion orifices, which are
sized and placed according to a unique pattern for each series of
heat exchangers. This makes production of small series of heat
exchangers inefficient and hampers production versatility. Against
that background an object of the present invention is to improve
the known heat exchanger, such that production thereof is
simplified and in particular rendered more efficient and
versatile.
SUMMARY OF THE INVENTION
[0004] According to the invention this is achieved by means of a
heat exchanger according to the preamble, said heat exchanger being
characterized in that said inlet tank and said outlet tank have
header plates, which form core interfaces and comprise throughout
identical tube insertion orifices for both the primary group of
tubes and the secondary group of tubes, in that the tubes being a
member of the primary group are base tubes, and in that the tubes
being a member of the secondary group are adaptation tubes, which
differ from the base tubes and are used to locally change
properties of the heat exchanger in critical areas of the heat
exchanger, and.
[0005] Use of header plates with throughout identical tube
insertion orifices, does of course necessitate use of tubes having
a throughout identical outer shape, as they otherwise would not fit
the header plates. This is however no problem, as tube
characteristics can be varied internally in different ways, e.g. by
choosing an appropriate tube wall thickness, by providing dimples
or turbulators or by using different tube inserts. Hence, the
invention renders it possible for instance to efficiently produce
small series of adapted heat exchangers by means of identical
header plates but different tubes at chosen positions.
[0006] According to one embodiment said secondary group of tubes in
order to prolong life of the heat exchanger comprises adaptation
tubes each providing an enhanced strength compared to a basic
strength provided by each one of said base tubes, wherein said
adaptation tubes are used in areas of the heat exchanger where
stress levels tend to be higher than a medium stress level of the
entire heat exchanger. Areas of a heat exchanger where such
strengthening tubes are useful are e.g. corner areas of a
substantially parellelepipedic heat exchanger core.
[0007] According to a further embodiment said adaptation tubes can
provide an enhanced strength by having a wall thickness exceeding a
wall thickness of the base tubes. Increasing tube wall thickness is
an easy way to enhance strength, but if the tubes are sheet metal
pipes, which is normal procedure in the art, it requires use of
differently gauged sheet metal for the tubes pertaining to the
first and the second group, respectively.
[0008] According to a further embodiment said adaptation tubes
provide an enhanced strength by comprising stiffening inserts
arranged in tube openings. Providing stiffening inserts is also an
easy way to enhance strength and makes use of tubes having an
identical wall thickness possible. However, production, insertion
and fastening of such stiffening inserts are aspects to be
considered.
[0009] According to a further embodiment said adaptation tubes
provide an enhanced strength by comprising stiffer turbulators than
turbulators arranged in said base tubes. In the art use of
so-called turbulators inside of heat exchanger tubes is quite
common. In the light of this, use of differently designed
turbulators to achieve a heat exchanger according to the invention
is an attractive solution.
[0010] According to a further embodiment said adaptation tubes
provide an enhanced strength by comprising internal stiffening
ribs. Internal stiffening ribs can be provided e.g. by embossing
sheet metal, of which tubes are produced, accordingly.
[0011] According to a further embodiment said adaptation tubes
provide an enhanced strength by comprising extra durable tube seams
created by means of all smooth tube walls. When producing tubes of
sheet metal, a brazing seam running along the tube is created. This
seam is rendered more durable if the original sheet is all smooth
and void of for instance embossed dimples.
[0012] According to a further embodiment said heat exchanger
comprises a first row of tubes and a second row of tubes, wherein
at least a plurality of the tubes of the first row belong to the
primary group of tubes and all tubes of the second row belong to
the secondary group of tubes. A solution like this can be
advantageous for instance if the heat exchanger is a coolant
radiator which is bolted to another unit, such as a charged air
cooler, which helps stabilizing the coolant radiator tube row next
to it.
[0013] According to a further embodiment said secondary group of
tubes in order to improve efficiency of the heat exchanger
comprises adaptation tubes, each providing a lower flow resistance
than a flow resistance provided by each one of said base tubes,
wherein said adaptation tubes are arranged in areas of the heat
exchanger where fluid flow levels tend to be lower than a medium
fluid flow level of the entire heat exchanger. Areas of a heat
exchanger where low flow tends to be a problem are mainly areas
remote of a fluid in or outlet, areas in the shadow of brackets or
the like, and areas immediately beneath a fluid inlet.
[0014] According to a further embodiment said adaptation tubes
provide a lower flow resistance by comprising turbulators causing a
lower flow resistance than turbulators being arranged in said base
tubes. As indicated before, turbulators inside of heat exchanger
tubes are quite common, and, thus, use of differently designed
turbulators to achieve a heat exchanger according to the invention
is an attractive solution.
[0015] According to a further embodiment said adaptation tubes
provide a lower flow resistance by having all smooth walls, while
said base tubes have dimpled walls. In the art dimples are used to
promote heat exchange. However, dimples do also cause some extra
flow resistance, which can effectively be avoided by all smooth
tube walls.
[0016] According to a further embodiment said heat exchanger
comprises a first row of tubes and a second row of tubes, wherein
all tubes of the first row belong to the secondary group of tubes
and all tubes of the second row belong to the primary group of
tubes. A solution like this can be advantageous for instance if the
fluid inlet and outlet of the heat exchanger tend to promote flow
through the second row.
[0017] According to a further embodiment said secondary group
comprises adaptation tubes, each providing a lower flow resistance
than a flow resistance provided by each one of said base tubes,
wherein said adaptation tubes are arranged in the heat exchanger in
an alternating pattern mixed with base tubes. A solution like this
is advantageous for instance if fluid flow through the heat
exchanger is highly dependent on rpm of an engine cooled by means
of the heat exchanger. In such a case alternate tubes in a certain
pattern help promoting an even flow of fluid through the entire
heat exchanger.
[0018] According to a further embodiment said adaptation tubes
provide a lower flow resistance by comprising turbulators causing a
lower flow resistance than turbulators being arranged in said base
tubes. The advantage of different turbulators has already been
discussed in the above.
[0019] According to a further embodiment said adaptation tubes
provide a lower flow resistance by having all smooth walls, while
said base tubes have dimpled walls. As indicated before, dimples
cause some extra flow resistance, which can effectively be avoided
by all smooth tube walls.
[0020] According to a further embodiment said alternating pattern
comprises a row of alternatingly a base tube and an adaptation
tube. In some instances it shows to be advantageous to mix tubes in
the indicated way to arrive at an optimum fluid flow distribution
at all fluid flow rates.
[0021] According to a further embodiment said alternating pattern
comprises a row of alternatingly two base tubes and an adaptation
tube. Again, the purpose of such a solution is to optimize
performance of a heat exchanger, especially at low to high fluid
flow rates.
[0022] According to a further embodiment said secondary group of
tubes is subdivided into at least two kinds of differently designed
tubes. Use of differently designed tubes for the second group of
tubes further enhances versatility of the heat exchanger according
to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In the drawings embodiments of heat exchangers according to
the invention are shown schematically. In the drawings:
[0024] FIG. 1 is a view from behind and shows a heat exchanger in
the form of a coolant radiator;
[0025] FIGS. 2 to 13 are views from top and show portions of header
plates of different embodiments of the coolant radiator of FIG.
1;
[0026] FIG. 14 is a view from front and shows a heat exchanger in
the form of a charged air cooler; and
[0027] FIGS. 15 to 20 are views from a side and show portions of
header plates of different embodiments of the charged air cooler of
FIG. 14.
DESCRIPTION OF A PREFERRED EMBODIMENT
[0028] In the following preferred embodiments of the invention are
described with reference being had to the drawings. In the drawings
like reference signs indicate similar elements.
[0029] In FIG. 1 a heat exchanger 1 is shown in a back view. The
heat exchanger 1 shown is a coolant radiator, which has a top inlet
tank 2 and a bottom outlet tank 3. Between these is a
parallelepipedic radiator core 6, which comprises a plurality of
vertical tubes 7, 8 and fins (not shown) there between. The tubes
7, 8 are tightly connected to the tanks 2, 3 by means of header
plates 9, 10 of the tanks 2, 3 and are used to lead coolant from a
fluid inlet 4 on the inlet tank 2 to a fluid outlet 5 on the outlet
tank 3 while being cooled on its way along fluid flow paths
illustrated by means of an arrow P.
[0030] Portions of the top plate 9 of the heat exchanger 1 are
illustrated in greater detail in FIGS. 2 to 13. In these figures
different embodiments of the heat exchanger 1 according to the
invention are shown when viewed from above inside the top tank 2.
The corresponding view of the opposite or bottom header plate 10 is
often identical but need not be. However, having studied the
description a person skilled in the art will anyway know how to
best implement the present invention.
[0031] In order to enhance cooling, tubes 7, 8 of the coolant
radiator can comprise dimples, which are shown in FIGS. 2 to 13,
where they are generally depicted 12. The dimples 12 are formed by
stamping of the tube sheet metal prior to final assembly of the
tubes 7, 8 into their flat shape. As can be seen in FIGS. 2 to 13
said dimples 12 form small protrusions inside of the tubes 7, 8.
The dimples 12 influence fluid flow inside of the tubes 7, 8 by
causing turbulence, which is beneficial for heat exchange but rises
pressure drop. Hence, in order to create an optimal heat exchanger
1, it is important to tune the heat exchanger 1 such that heat
exchange is maximized while pressure drop is kept low, especially
at different flow rates of the fluid passing trough the tubes 7, 8
along said fluid flow paths P.
[0032] To render that possible in an effective way the header
plates 9, 10 of the heat exchanger 1 according to the invention
comprise throughout identical tube insertion orifices 11. In these
tubes 7, 8 belonging to a primary and a secondary group of
differently designed tubes are inserted in a tightly fitting way
and fastened, e. g. by brazing.
[0033] The tubes 7 belonging to said primary group are in this
context called base tubes 7, as they so to say fulfill basic heat
exchange demands of a heat exchanger 1. The tubes 8 belonging to
said secondary group are in this context instead called adaptation
tubes 8, as they are used to locally change properties of the heat
exchanger 1 in critical areas. Where these critical areas are to be
found and how they are dealt with according to the invention is
explained below by means of examples relating only to the top
header plate 9.
[0034] The header plates 9 of FIGS. 2 to 13 reveal that all
embodiments of the heat exchanger 1 shown in the drawings
illustrate a two row coolant radiator. However, this does not have
to be the case and is chosen only to exemplify some typical layout
solutions within the frame of the invention as claimed. In other
words, one single row of tubes 7, 8 or multiple rows of tubes 7, 8
as well as tubes 7, 8 turned in another way in relation to the
header plates 9 are also within the scope.
[0035] FIG. 2 is used to illustrate an end portion, such as the top
left portion of a heat exchanger 1 of FIG. 1. As can be seen, of
the totally twenty tubes shown in FIG. 2, the fourteen to the right
(seven per row) are depicted 7. Hence they are so-called base tubes
7 of the primary group of tubes, which in this case means that they
have a standard tube wall thickness and dimples 12 on the inside.
The remaining six tubes to the left (three per row) are instead
so-called adaptation tubes 8 of the secondary group, which in this
case means that they have a greater tube wall thickness and dimples
12 on the inside. The adaptation tubes 8 help stabilizing the heat
exchanger 1 corner, where stress usually is higher, but rises
pressure drop to a certain extent.
[0036] FIG. 3 illustrates a mid section somewhere along a header
plate 9. This time a group of eight adaptation tubes 8 (four per
row) corresponding to the ones of FIG. 2 are arranged amid the base
tubes 7. Again the purpose is to stabilize the heat exchanger 1 or
alternatively to limit flow of fluid by causing an increased
pressure drop, or both.
[0037] FIGS. 4 and 5 do also illustrate a mid section somewhere
along a header plate 9. The tubes 7 and 8 belonging to the primary
and secondary group correspond to the ones described above and are
arranged in an alternating pattern comprising rows of alternatingly
a base tube 7 and a adaptation tube 8 or rows of alternatingly two
base tubes 7 and a adaptation tube 8. By causing different pressure
drops, the tubes 7, 8 help distribute flow evenly over the entire
heat exchanger 1, especially at low fluid flow rates, which helps
improving efficiency. However, the adaptation tubes 8 with their
thicker gauge are of course beneficial for heat exchanger integrity
as well.
[0038] FIG. 6 illustrates an arbitrary section along a header plate
9, while FIG. 7 illustrates an end or corner portion, such as a top
left end or corner portion of the heat exchanger 1 of FIG. 1. In
both embodiments base tubes 7 and adaptation tubes 8 of the same
kind as before are used, that is base tubes 7 with a standard wall
gauge and adaptation tubes 8 with a greater wall gauge.
[0039] In the embodiment of FIG. 6 there is one row of solely base
tubes 7 and one row of solely adaptation tubes 8. The base tube row
is preferably arranged close to a solid support, such as a charged
air cooler, which helps withstand outer forces, while the more
exposed part of the heat exchanger 1 shows reinforced tubes 8 only.
The embodiment of FIG. 7 is much alike, differing only in that just
a few tubes in a corner portion of the heat exchanger 1 comprise
strong adaptation tubes 8, such as a corner holding a fastening
bracket (not shown). In that way it is possible to preserve heat
exchanger integrity without causing excessive pressure drop.
[0040] In FIG. 8 the base tubes 7 are again formed by dimpled tubes
having a standard wall thickness and being arranged for instance in
a mid sector along a header plate 9. The adaptation tubes 8, which
for instance are arranged at an end portion of the header plate 9,
are this time formed by all flat tubes void of any dimples. That
makes it possible to strengthen the tubes 8 thanks to a smooth
unaffected brazing seem, which is indicated by means of an arrow
13.
[0041] An adaptation tube 8 of this kind renders it possible to
strengthen the structure without a pressure drop increase or a
thicker tube wall thickness, but lessens heat rejection to some
extent.
[0042] In the embodiment shown in FIG. 9 the same kinds of tubes 7,
8 are used as in the embodiment in FIG. 8. The difference lies in
that this time there is a row with only dimpled base tubes 7 and
all flat adaptation tubes 8. As described before, such a row
solution can be used to influence fluid flow, in strengthening
purposes, or both.
[0043] FIGS. 10 and 11 reveal embodiments, which show that the
group of adaptation tubes 8 can comprise more than one different
kind of adaptation tubes, such as two in FIG. 10 and three in FIG.
11. As before there are standard dimpled base tubes 7, which in the
embodiment of FIG. 10 are arranged e.g. in a mid section along a
header plate 9 of a heat exchanger 1, and in the embodiment of FIG.
11 are arranged in a mid section, too, but only in one of two rows
of tubes of a heat exchanger 1. In FIG. 10 the remaining tubes,
that is the adaptation tubes 8 at an end of the header plate 9 in
question, comprise both eight outer tubes 8 with an extremely thick
tube wall but yet provided with dimples 11, and six intermediate
tubes 8 with a not quite as thick tube wall and dimples between
said outer tubes 8 and said base tubes 7. In FIG. 11 the dimpled
base tubes 7 are arranged in just one row in a mid sector of a
header plate 9 of a two row heat exchanger. To their left in the
embodiment shown in FIG. 11 and in the same row there are dimpled
adaptation tubes 8 having a greater wall thickness. In the other
row next to the base tubes 7 there are all smooth adaptation tubes
8 having a wall thickness corresponding to the one of the base
tubes 7. Further, in the other row next to the dimpled adaptation
tubes 8 again there are all smooth adaptation tubes 8, but these
have a greater wall thickness than the ones next to the base tubes
7. In common the embodiments of FIGS. 10 and 11 show that there are
few limits when it comes to optimizing a heat exchanger 1 by means
of the invention, irrespective if one wishes to better mechanical
strength or life of a heat exchanger or better efficiency or
performance of a heat exchanger.
[0044] In FIG. 12 a further embodiment of a heat exchanger 1
according to the invention is illustrated. As before the header
plate 9 shown in FIG. 12 has throughout identical tube insertion
orifices 12. In these are fastened dimpled base tubes 7 in two rows
to the right of eight (four in each row) adaptation tubes 8. These
can be smooth or dimpled but have an end portion which enables
insertion of a strengthening tube insert 14. The tube insert 14 is
adapted to be brazed to the tube 8 and stiffens said end portion
considerably without affecting fluid flow all too much.
[0045] In FIG. 13 a final embodiment of a header plate 9 of the
heat exchanger 1 of FIG. 1 is shown. The kind and placement of the
base tubes 7 corresponds exactly to the embodiment of FIG. 12.
Hence, again the adaptation tubes 8 are the ones that differ. This
time they provide an enhanced strength by comprising internal
stiffening ribs 15, which can be stamped just like dimples 12.
Preferably the stiffening ribs 15 of the adaptation tubes 8 meat in
a central part of the tubes 8 and interconnect by means of a
brazing seam (not depicted). Influence on fluid flow is comparable
to the one of the dimpled base tubes 7. In other words, the purpose
of these adaptation tubes 8 in mainly a structural one.
[0046] I FIG. 14 a heat exchanger 21 is shown in a front view. The
heat exchanger 21 shown is a charged air cooler (CAC), which has a
left inlet tank 22 and a right outlet tank 23. Between these is a
parallelepipedic CAC core 26, which comprises a plurality of
horizontal tubes 27, 28 and fins (not shown) there between. The
tubes 27, 28 are tightly connected to the tanks 22, 23 by means of
header plates 29, 30 and are used to lead charged air from a fluid
inlet 24 on the inlet tank 22 to a fluid outlet 25 on the outlet
tank 23 while being cooled on its way along fluid flow paths
illustrated by means of an arrow P.
[0047] In order to enhance cooling, the tubes 27, 28 of a CAC 21
are usually provided with turbulators, by which are meant formed
metal sheet inserts brazed to the inside of said tubes. In the
drawings in FIGS. 15 to 20 the turbulators are generally depicted
32, 33 and shown to be substantially corrugated. However, in
reality they can have a totally different shape. Therefore the
versions shown in FIGS. 15 to 20 are only to be viewed as mere
examples.
[0048] Depending on temperatures, pressures and geometry, in a CAC
21 fluid flow through different tubes 27, 28 of the CAC core 26 is
difficult to distribute evenly. Due to rather high temperatures in
a CAC 21, this can easily lead to structural failure. Further,
inefficiently used tubes 27, 28 do lower overall efficiency.
[0049] To mitigate these problems tanks 22, 23 of a CAC 21 usually
are formed such that they taper from a fluid inlet 24 or fluid
outlet 25, but that measure alone does not really suffice. Hence,
according to the principle of the present invention even for the
CAC heat exchanger 21 tubes 27, 28 belonging to two different
groups of tubes are used for flow and temperature tuning and
structural integrity. How this is done is illustrated by means of
the embodiments shown in FIGS. 15 to 20.
[0050] In FIG. 15 a portion of the left header plate 29 of FIG. 14
is shown. The corresponding view of the opposite or right header
plate 30 is often identical but need not be. However, having
studied the description a person skilled in the art will anyway
know how to best implement the present invention.
[0051] The header plate 29 comprises a number of identical tube
insertion orifices 31, in which tubes 27, 28 fit tightly by being
brazed or welded. The insertion orifices 31 are in this case
arranged horizontally and in a single row, one above the other.
However, they could also be arranged vertically and/or in two or
more rows.
[0052] In FIG. 15 the bottom three tubes are so-called base tubes
27 which belong to a primary group of tubes, whereas the top three
tubes are so-called adaptation tubes 28 and belong to a secondary
group of tubes. The base tubes 27 and adaptation tubes 28 differ in
that they comprise differently shaped turbulators 32, 33. The ones
32 of the base tubes 27 show a wide undulation pattern, which gives
them a lower heat dissipation capacity than the more narrowly
undulated turbulators 33 of the adaptation tubes 28. On the other
hand, due the turbulators 33 the adaptation tubes 28 cause a higher
pressure drop, which makes fluid more prone to pass through the
base tubes 27. In other words the adaptation tubes can be used to
steer excessive fluid flow away from parts of the CAC, such as
highly loaded parts close to the fluid inlet 24.
[0053] The embodiment of FIG. 16 is quite similar to the one of
FIG. 15. It differs only in that the undulations of the turbulators
32 of the base tubes 27 are undulated just as narrow as the ones 33
of the adaptation tubes 28. However, the turbulators 33 of the
adaptations tubes 28 are made of a thicker metal sheet, which leads
to the desired difference between the two types of tubes 27, 28,
with an extra emphasis on durability.
[0054] In FIG. 17 the bottom three tubes are base tubes 27
corresponding to the ones of FIG. 16. In the top three or
adaptation tubes 28, the turbulators 33 are much alike the
turbulators 32 of the base tubes 27 but have curled flanges 34
which stiffen short sides of the adaptation tubes 28. Said flanges
34 do hardly influence fluid flow, which means this embodiment
mainly is suited to extend life in critical areas of a CAC 21.
[0055] In FIGS. 18 and 19 the bottom three tubes are base tubes 27
belonging to the primary group of tubes. As in some other cases
before they differ in that their turbulators 32, 33 show
differently wide undulations. The top three tubes in both figures
are instead alike and comprise identically undulated turbulators as
well as tubular stiffening inserts 35 fitting exactly into the
adaptation tubes 28. The stiffening inserts 35 do influence fluid
flow and lead to an enhanced strength. Hence use of tubes 27, 28
according to the embodiments of FIGS. 18 and 19 is advantageous in
heat exchanger areas where load is high, such as next to an inlet
24.
[0056] In the final drawing figure, FIG. 20, there are three base
tubes 27 at the bottom and three adaptation tubes 28 at the top,
all tubes 27, 28 according to the present invention being inserted
in identical tube insertion orifices 31 of a header plate 29. The
turbulators 32, 33, which are inserted in both types of tubes are
substantially alike, except for the fact that the ones 33 in the
adaptation tubes 28 are a little smaller. This is due to the fact
that the adaptation tubes 28 have a greater wall thickness than the
base tubes 27. This limits fluid flow to some degree but leads to
an enhanced overall strength.
[0057] A person skilled in the art is aware that alterations of the
embodiments described are possible within the scope of the appended
claims.
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