U.S. patent application number 12/521892 was filed with the patent office on 2010-02-04 for heat exchanger and method.
Invention is credited to Steven P. Meshenky, Dan R. Raduenz.
Application Number | 20100025024 12/521892 |
Document ID | / |
Family ID | 39644864 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100025024 |
Kind Code |
A1 |
Meshenky; Steven P. ; et
al. |
February 4, 2010 |
HEAT EXCHANGER AND METHOD
Abstract
A heat exchanger including a first flow path for a first working
fluid, a second flow path for a second working fluid, a tube at
least partially defining one of the first and second flow paths,
and a corrugated insert secured to the tube and positioned along
the first flow path. A structural deficit is provided at a location
on the insert such that structural failures occur at the location
in preference to other locations on the insert.
Inventors: |
Meshenky; Steven P.;
(Racine, WI) ; Raduenz; Dan R.; (Racine,
WI) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH LLP
100 E WISCONSIN AVENUE, Suite 3300
MILWAUKEE
WI
53202
US
|
Family ID: |
39644864 |
Appl. No.: |
12/521892 |
Filed: |
January 23, 2008 |
PCT Filed: |
January 23, 2008 |
PCT NO: |
PCT/US08/51747 |
371 Date: |
July 1, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60881919 |
Jan 23, 2007 |
|
|
|
Current U.S.
Class: |
165/164 ;
165/173 |
Current CPC
Class: |
F28F 2265/00 20130101;
F28F 2240/00 20130101; F28F 3/025 20130101; F28D 7/1684 20130101;
F28F 9/0219 20130101; F28F 2275/122 20130101; F28D 9/0031 20130101;
F02M 26/32 20160201 |
Class at
Publication: |
165/164 ;
165/173 |
International
Class: |
F28F 3/00 20060101
F28F003/00; F28F 1/10 20060101 F28F001/10; F28F 9/02 20060101
F28F009/02 |
Claims
1. A heat exchanger comprising: a first flow path for a first
working fluid; a second flow path for a second working fluid; a
corrugated insert positioned along the first flow path; a
structural deficit provided at a location on the insert such that
structural failures occur at the location in preference to other
locations on the insert; and a tube at least partially defining one
of the first and second flow paths, the insert being secured to the
tube.
2. The heat exchanger of claim 1, wherein the structural deficit
comprises a groove.
3. The heat exchanger of claim 1, wherein the structural deficit
comprises a staggered groove.
4. The heat exchanger of claim 1, wherein the corrugated insert
comprises a peak and an adjacent valley and wherein the structural
deficit is positioned between the peak and the valley.
5. The heat exchanger of claim 4, wherein the peak and valley
extend along a longitudinal dimension of the insert and the
structural deficit extends along a portion of the longitudinal
dimension of the insert in a direction substantially parallel to a
fold of the insert.
6. The heat exchanger of claim 4, wherein the structural deficit is
positioned substantially equidistantly between the peak and valley
such that structural failures occur at a midpoint between the peak
and valley.
7. The heat exchanger of claim 1, wherein the insert comprises
adjacent folds such that the insert extends between opposing
surfaces of the tube and is secured to the surfaces of the tube at
the folds.
8. The heat exchanger of claim 7, wherein the structural deficit is
located midway along a height of the insert between the opposing
surfaces of the tube.
9. The heat exchanger of claim 7, wherein the structural deficit is
spaced away from the folds of the insert.
10. The heat exchanger of claim 7, wherein the folds are secured to
the surfaces of the tube by one of welded, soldered, and brazed
connections.
11. A heat exchanger comprising: a header; a tube secured to the
header; and a corrugated insert secured to at least one surface of
the tube, the insert having a groove formed along at least a
portion of a length of the insert and spaced apart from the surface
of the tube to which the insert is secured.
12. The heat exchanger of claim 11, wherein the insert defines
adjacent legs, and wherein the groove is located along one of the
legs.
13. The heat exchanger of claim 12, wherein at least a portion of
one of the legs has a wavy cross-section.
14. The heat exchanger of claim 12, wherein the insert is secured
between opposing surfaces of the tube, and wherein the groove is
positioned along the insert such that the insert remains secured to
the opposing surfaces after a structural failure.
15. The heat exchanger of claim 14, wherein the legs of the insert
provide sufficient structural support for the opposing surfaces of
the tube after a structural failure.
16. The heat exchanger of claim 12, wherein the corrugated insert
comprises a peak and an adjacent valley and wherein the groove is
positioned between the peak and the valley.
17. The heat exchanger of claim 12, wherein the corrugated insert
comprises a peak and an adjacent valley, and wherein the groove is
positioned substantially equidistantly between the peak and valley
such that the structural failures occur at a midpoint between the
peak and valley.
18. The heat exchanger of claim 12, wherein the groove has a
cross-section that is substantially V-shaped.
19. A heat exchanger having a tube and an insert supported by the
tube, the insert comprising: a corrugation defining a peak and an
adjacent valley; a groove extending along a longitudinal dimension
of the insert between the peak and the adjacent valley and
providing a preferred location for structural failures.
20. The heat exchanger of claim 19, wherein the groove is
positioned substantially equidistantly between the peak and the
valley such that structural failures occur at a midpoint between
the peak and the valley.
21. The heat exchanger of claim 19, wherein the groove is located
at a maximum distance between the peak and the valley.
22. The heat exchanger of claim 19, wherein the insert is attached
to opposing surfaces of the tube in at least one location along at
least one of the peak and the valley.
23. The heat exchanger of claim 19, wherein the groove extends
substantially along the entire longitudinal dimension of the
insert.
24. The heat exchanger of claim 19, wherein the longitudinal
dimension of the insert terminates in opposing ends of the insert,
and wherein the groove extends from an end to a location along the
longitudinal dimension of the insert.
25. The heat exchanger of claim 24, and further comprising a header
into which an end of the tube extends, wherein the insert extends
substantially the entire length of the tube and the groove extends
to a location where the tube connects to the header.
26. The heat exchanger of claim 24, and further comprising a header
into which an end of the tube extends, wherein the insert extends
substantially the entire length of the tube and the groove extends
beyond a location where the tube connects to the header.
27. A method of assembling a heat exchanger comprising the steps
of: providing a heat exchanger tube; positioning an insert in the
tube; connecting the insert to a surface of the tube; forming a
structural deficiency along at least a portion of a length of the
insert at a maximum distance from a point of connection between the
insert and the surface of the tube so that failures occur along the
structural deficiency.
28. The method of claim 27, wherein forming the structural
deficiency includes forming a groove, and wherein the structural
deficiency is formed having a cross-section that is one of
substantially U-shaped, V-shaped, or rectangular.
29. The method of claim 27, wherein the structural deficiency is
formed by one of scoring, stamping, and etching.
30. The method of claim 27, wherein the insert is connected to the
surface of the tube by one of brazing, soldering, or welding.
31. The method of claim 27, and further comprising folding the
insert to form alternating peaks and valleys.
32. The method of claim 31, wherein the structural deficiency is
formed prior to the folding of the insert.
33. The method of claim 31, wherein the structural deficiency is
formed after the folding of the insert.
34. The method of claim 31, wherein the peaks and valleys of the
insert are connected to opposing surfaces of the tube.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. provisional
application Ser. No. 60/881,919 filed Jan. 23, 2007.
FIELD OF THE INVENTION
[0002] The present invention relates to heat exchangers and, more
particularly, to an exhaust gas recirculation cooler, a method of
assembling the same, and a method of operating the same.
SUMMARY
[0003] In some embodiments, the present invention provides a heat
exchanger defining a flow path for a first working fluid and a flow
path for a second working fluid, a tube at least partially defining
one of the first and second flow paths, and a corrugated insert
secured to the tube and positioned along the flow path of the first
working fluid. In some embodiments, a structural deficit is
provided at a location on the insert so that failures occur at that
location.
[0004] The present invention also provides a heat exchanger having
a header and a tube secured to the header. A corrugated insert can
be secured to a surface of the tube and can include a groove formed
along at least a portion of a length of the insert and spaced apart
from the surface of the tube to which the insert is secured. In
some embodiments, the corrugated insert can be secured between two
opposing surfaces of the tube and the groove can be formed midway
along a height of the insert.
[0005] In some embodiments, the present invention provides a heat
exchanger having a tube and an insert supported by the tube. The
insert can have a corrugated shape with a peak and an adjacent
valley and a groove extending along a longitudinal dimension of the
insert between the peak and the valley such that structural
failures occur at a preferred location between the peak and the
valley.
[0006] The present invention also provides a method of assembling a
heat exchanger including providing a heat exchanger tube and
positioning an insert in the tube. The method can also include the
steps of connecting the insert to a surface of the tube and forming
a structural deficiency along at least a portion of a length of the
insert at a maximum distance from a point of connection between the
insert and the surface of the tube so that failures occur along the
structural deficiency.
[0007] Other aspects of the invention will become apparent by
consideration of the detailed description and accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of a heat exchanger according
to some embodiments of the present invention.
[0009] FIG. 2 is a partially cut-away view of a portion of the heat
exchanger shown in FIG. 1.
[0010] FIG. 3 is a perspective view of a portion of a tube of the
heat exchanger shown in FIG. 1.
[0011] FIG. 4 is an exploded view of a portion of a tube and an
insert of the heat exchanger shown in FIG. 1.
[0012] FIG. 5 is an end view of a portion of a tube and an insert
of the heat exchanger shown in FIG. 1.
[0013] FIG. 6 is an exploded view of a tube and an insert of a heat
exchanger according to another embodiment of the present
invention.
[0014] FIG. 7 is an end view of a portion of a tube and an insert
of the heat exchanger shown in FIG. 6.
DETAILED DESCRIPTION
[0015] Before any embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways. Also, it is to be understood that the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limiting. The use of "including,"
"comprising," or "having" and variations thereof herein is meant to
encompass the items listed thereafter and equivalents thereof as
well as additional items.
[0016] Unless specified or limited otherwise, the terms "mounted,"
"connected," "supported," and "coupled" and variations thereof are
used broadly and encompass both direct and indirect mountings,
connections, supports, and couplings. Further, "connected" and
"coupled" are not restricted to physical or mechanical connections
or couplings.
[0017] Also, it is to be understood that phraseology and
terminology used herein with reference to device or element
orientation (such as, for example, terms like "central," "upper,"
"lower," "front," "rear," and the like) are only used to simplify
description of the present invention, and do not alone indicate or
imply that the device or element referred to must have a particular
orientation. In addition, terms such as "first" and "second" are
used herein for purposes of description and are not intended to
indicate or imply relative importance or significance.
[0018] FIGS. 1-5 illustrate a heat exchanger 10 according to some
embodiments of the present invention. In some embodiments,
including the illustrated embodiment of FIGS. 1-5, the heat
exchanger 10 can operate as an exhaust gas recirculation cooler
(EGRC) and can be operated with the exhaust system of a vehicle. In
other embodiments, the heat exchanger 10 can be used in other
(e.g., non-vehicular) applications, such as, for example, in
electronics cooling, industrial equipment, building heating and
air-conditioning, and the like. In addition, it should be
appreciated that the heat exchanger 10 of the present invention can
take many forms, utilize a wide range of materials, and can be
incorporated into various other systems.
[0019] During operation and as explained in greater detail below,
the heat exchanger 10 can transfer heat energy from a high
temperature first working fluid (e.g., exhaust gas, water, engine
coolant, CO.sub.2, an organic refrigerant, R12, R245fa, air, and
the like) to a lower temperature second working fluid (e.g.,
exhaust gas, water, engine coolant, CO.sub.2, an organic
refrigerant, R12, R245fa, air, and the like). In addition, while
reference is made herein to transferring heat energy between two
working fluids, in some embodiments of the present invention, the
heat exchanger 10 can operate to transfer heat energy between three
or more fluids. Alternatively or in addition, the heat exchanger 10
can operate as a recuperator and can transfer heat energy from a
high temperature location of a heating circuit to a low temperature
location of the same heating circuit. In some such embodiments, the
heat exchanger 10 can transfer heat energy from a working fluid
traveling through a first portion of the heat transfer circuit to
the same working fluid traveling through a second portion of the
heat transfer circuit.
[0020] As shown in FIG. 1, the heat exchanger 10 can include a
first header 18 and a second header 20 positioned at respective
first and second ends 22, 24 of a stack of heat exchanger tubes 26.
In the illustrated embodiment of FIGS. 1-5, the first header 18
includes a first collecting tank 30 and the second header 20
includes a second collecting tank 32. In other embodiments, the
heat exchanger 10 can include a single header 18 located at one of
the first and second ends 22, 24 or at another location on the heat
exchanger 10.
[0021] As shown in FIGS. 1-5, each of the tubes 26 can be secured
to the first and second headers 18, 20 such that a first working
fluid flowing through the heat exchanger 10 is maintained separate
from a second working fluid flowing through the heat exchanger 10.
More specifically, the heat exchanger 10 defines a first flow path
(represented by arrows 34 in FIG. 1) for the first working fluid
and a second flow path (represented by arrows 36 in FIG. 1) for a
second working fluid, and the first and second flow paths 34, 36
are separated such that the first working fluid is prevented from
entering the second flow path 36 and such that the second working
fluid is prevented from entering the first flow path 34.
[0022] In some embodiments, such as the illustrated embodiment of
FIGS. 1-5, the tubes 26 are secured to the first and second headers
18, 20 such that the first working fluid enters the heat exchanger
10 through a first inlet aperture 40 in the first header 18,
travels through the heat exchanger 10 along the first flow path 34,
and is prevented from entering the second flow path 36. In these
embodiments, the tubes 26 can be secured to the first and second
headers 18, 20 such that the second working fluid enters the heat
exchanger 10 through a second inlet aperture 42 in the second
header 20, travels through the heat exchanger 10 along the second
flow path 36, and is prevented from entering the first flow path
34.
[0023] In some such embodiments, the first flow path 34 extends
through the first inlet aperture 40 in the first header 18, through
the tubes 26, and out of the heat exchanger 10 through a first
outlet aperture 44 in the second header 20, and the second flow
path 36 extends through the second inlet aperture 42, around and
between the tubes 26 (e.g., along outer surfaces 45 of the tubes
26), and out of the heat exchanger 10 through a second outlet
aperture 46 in the first header 18.
[0024] In other embodiments, the tubes 26 can have other
orientations and configurations and the first and second flow paths
34, 36 can be maintained separate by dividers, inserts, partitions,
and the like. In still other embodiments, the first flow path 34
can extend through some of the tubes 26 while the second flow path
36 can extend through other tubes 26.
[0025] Alternatively or in addition, dividers 38 can be positioned
in the first and/or second headers 18, 20 to separate or at least
partially separate the first and second flow paths 34, 36. In some
embodiments, such as the illustrated embodiment of FIGS. 1-5, the
dividers 38 can be contoured to closely engage the interior of the
first and/or second headers 18, 20 and to prevent the first and/or
second working fluids from leaking between the interior walls of
the first and/or second headers 18, 20 and the outer perimeter of
the dividers 38.
[0026] As shown in FIG. 2, the dividers 38 can have apertures 39
sized to receive one or more of the tubes 26. In embodiments such
as the illustrated embodiment of FIGS. 1-5 having dividers 38
supported in the first and/or second headers 18, 20, the first
working fluid flowing along the first flow path 34 can enter the
tubes 26 through apertures 39 formed in the dividers 38. In these
embodiments, the dividers 38 prevent the second working fluid from
entering the tubes 26. In these embodiments, the dividers 38 can
also direct the second working fluid from the second inlet aperture
42 between adjacent tubes 26 and can prevent the second working
fluid from flowing into the tubes 26. The dividers 38 can also
prevent the first working fluid from flowing between the tubes
26.
[0027] In the illustrated embodiment of FIGS. 1-5, the heat
exchanger 10 is configured as a cross-flow heat exchanger such that
the first flow path 34 or a portion of the first flow path 34 is
opposite to or counter to the second flow path 36 or a portion of
the second flow path 36. In other embodiments, the heat exchanger
10 can have other configurations and arrangements, such as, for
example, a parallel-flow or a counter-flow configuration.
[0028] In the illustrated embodiment of FIGS. 1-5, the heat
exchanger 10 is configured as a single-pass heat exchanger with the
first working fluid traveling along the first flow path 34 through
at least one of a number of tubes 26 and with the second working
fluid traveling along the second flow path 36 between adjacent
tubes 26. In other embodiments, the heat exchanger 10 can be
configured as a multi-pass heat exchanger with the first working
fluid traveling in a first pass through one or more of the tubes 26
and then traveling in a second pass through one or more different
tubes 26 in a direction opposite to the flow direction of the first
working fluid in the first pass. In these embodiments, the second
working fluid can travel along the second flow path 36 between
adjacent tubes 26.
[0029] In yet other embodiments, the heat exchanger 10 can be
configured as a multi-pass heat exchanger with the second working
fluid traveling in a first pass between a first pair of adjacent
tubes 26 and then traveling in a second pass between another pair
of adjacent tubes 26 in a direction opposite to the flow direction
of the second working fluid in the first pass. In these
embodiments, the first working fluid can travel along the first
flow path 34 through at least one of the tubes 26.
[0030] In the illustrated embodiment of FIGS. 1-5, the heat
exchanger 10 includes seven tubes 26, each of which has a
substantially rectangular cross-sectional shape. In other
embodiments, the heat exchanger 10 can include one, two, three,
four, five, six, eight, or more tubes 26, each of which can have a
triangular, circular, square or other polygonal, oval, or irregular
cross-sectional shape.
[0031] As shown in FIG. 2, the tubes 26 are assembled together in a
stacking direction 50. In some embodiments, such as the illustrated
embodiment of FIGS. 1-5, reinforcing plates 52 can be added to the
stack of tubes 26 to at least partially enclose the tubes 26. In
some such embodiments, reinforcing plates 52 can be positioned
adjacent to the top and bottom of the stack of tubes 26.
Alternatively or in addition, a housing can be provided around at
least some of the tubes 26. In embodiments having reinforcing
plates 52 and/or a housing, the reinforcing plates 52 and/or the
housing can protect the tubes 26 from the mechanical effects of
temperature fluctuations.
[0032] As mentioned above, in some embodiments, the second flow
path 36 or a portion of the second flow path 36 can extend across
the outer surface 45 of one or more of the tubes 26. In some such
embodiments, a housing can be provided around the tubes 26 to
prevent the second fluid from leaking out of the heat exchanger 10
between adjacent tubes 26. Alternatively or in addition, ribs 56
can be formed along the outer surfaces 45 of the tubes 26 to at
least partially define channels 58.
[0033] As shown in FIG. 1, the heat exchanger 10 can include
connectors 54 for supporting the heat exchanger 10 and/or for
securing the heat exchanger 10 to an external structure. In some
embodiments, such as the illustrated embodiment, connectors 54 can
be provided on the collecting tanks 22, 23. As shown in FIG. 1, the
second inlet aperture 42 and/or the second outlet aperture 46 can
be positioned along the connectors 54. As also shown in FIG. 1, a
sealing groove or sealing rim 55 can be formed around the second
inlet aperture 42 and/or the second outlet aperture 46 so that the
heat exchanger 10 can be directly fastened to an external structure
and so that the second working fluid does not leak out of the heat
exchanger 10 around the second inlet aperture 42 and/or the second
outlet aperture 46.
[0034] In embodiments, such as the illustrated embodiment of FIGS.
1-5, having outwardly extending ribs 56, the ribs 56 of each tube
26 can be secured to an adjacent tube 26. In some such embodiments,
the ribs 56 of one tube 26 can be soldered, brazed, or welded to an
adjacent tube 26. In other embodiments, adjacent tubes 26 can be
secured together with inter-engaging fasteners, other conventional
fasteners, adhesive or cohesive bonding material, by an
interference fit, etc.
[0035] Additional elevations, recesses, or deformations 60 can also
or alternatively be provided on the outer surfaces 45 of the tubes
26 to provide structural support to the heat exchanger 10, prevent
the deformation or crushing of one or more tubes 26, maintain a
desired spacing between adjacent tubes 26, improve heat exchange
between the first and second working fluids, and/or generate
turbulence along one or both of the first and second flow paths 34,
36.
[0036] In some embodiments, the heat exchanger 10 can include
inserts 66 to improve heat transfer between the first and second
working fluids as the first and second working fluids travel along
the first and second flow paths 34, 36, respectively. As shown in
FIGS. 1-5, the inserts 66 can be positioned in the tubes 26.
Alternatively or in addition, inserts 66 can be positioned between
adjacent tubes 26. In other embodiments, inserts 66 can be
integrally formed with the tubes 26 and can extend outwardly from
the outer surfaces 45 of the tubes 26.
[0037] In the illustrated embodiment of FIGS. 1-5, an insert 66 is
supported in each of the tubes 26, and extends along the entire
length or substantially the entire length of each of the tubes 26
between opposite ends 68 of the tubes 26. In other embodiments, an
insert 26 can be supported in only one or less than all of the
tubes 26, and the insert(s) 66 can extend substantially the entire
length of the tube(s) 26 between opposite ends 68 of the tube(s)
26, or alternatively, the insert 66 can extend through the tube(s)
26 along substantially less than the entire length of the tube(s)
26. In still other embodiments, two or more inserts 66 can be
supported by or in each tube 26.
[0038] In some embodiments, the inserts 66 can be secured to the
tubes 26. In some such embodiments, the inserts 66 are soldered,
brazed, or welded to the tubes 26. In other embodiments, the
inserts 26 can be connected to the tubes 26 in another manner, such
as, for example, by an interference fit, adhesive or cohesive
bonding material, fasteners, etc.
[0039] In some embodiments, such as the illustrated embodiment of
FIGS. 1-5, the ends 68 of the tubes 26 can be press-fit into one or
both of the first and second headers 18, 20. In some such
embodiments, the ends 68 of the tubes 26 and the inserts 66
supported in the tubes 26 or between the tubes 26 can be at least
partially deformed when the tubes 26 and/or the inserts 66 are
press-fit into the first and/or second headers 18, 20. In some such
embodiments, the tubes 26 and/or the inserts 66 are pinched and
maintained in compression to secure the tubes 26 and/or the inserts
66 in a desired orientation and to prevent leaking.
[0040] In the illustrated embodiment of FIGS. 1-5, the inserts 66
are formed from folded sheets of metal. In other embodiments, the
inserts 66 can be cast or molded in a desired shape and can be
formed from other materials (e.g., aluminum, iron, and other
metals, composite material, and the like). In still other
embodiments, the inserts 66 can be cut or machined to shape in any
manner, can be extruded or pressed, can be manufactured in any
combination of such operations, and the like.
[0041] As shown in FIGS. 2, 4, and 5, the inserts 66 can be
corrugated and can have a series of alternating peaks 72 and
valleys 74. As also shown in FIGS. 2, 4, and 5, the peaks 72 and
valleys 74 can engage respective upper and lower interior sides of
a tube 26, and flanks 76 can extend (e.g., in a generally vertical
direction in the illustrated embodiment of FIGS. 2, 4, and 5)
between adjacent peaks 72 and valleys 74.
[0042] In some embodiments, such as the illustrated embodiment of
FIGS. 6 and 7 (described in detail below), the flanks 76 can extend
in a generally linear direction between opposite interior sides
(e.g., between upper and lower opposing sides in the illustrated
embodiment of FIGS. 6 and 7) of the tubes 26. In other embodiments,
such as the illustrated embodiment of FIGS. 1-5, the flanks 76 can
extend in a non-linear direction between the opposite interior
sides (e.g., between upper and lower sides in the illustrated
embodiment of FIGS. 1-5) of the tubes 26. In the illustrated
embodiments, the peaks 72 and valleys 74 extend along a
longitudinal dimension of the insert 66 and the tube 26. In other
embodiments, the insert 66 may be in contact with only one side of
the tube 26.
[0043] As shown in FIGS. 2, 4, and 5, in some such embodiments, the
flanks 76 can have a generally wavy cross-sectional shape. In other
embodiments, the inserts 66 can have other shapes and
configurations. For example, in some embodiments, the inserts 66
can have pointed, squared, or irregularly shaped peaks 72 and/or
valleys 74. In other embodiments, the inserts 66 can have a
saw-toothed or sinusoidal profile.
[0044] In embodiments, such as the illustrated embodiment of FIGS.
1-5, having a wavy cross-sectional shape, the inserts 66 operate as
springs to absorb or at least partially absorb vibrations and/or to
absorb expansions and contractions of the inserts 66 caused by
fluctuating inlet temperatures of the first and/or second working
fluids. In some such embodiments, the elasticity of the wavy
inserts 66 prevents and/or reduces cracking and breaking of the
inserts 66. Alternatively or in addition, the elasticity of the
wavy inserts 66 prevents and/or reduces cracking and breaking of
connections (e.g., solder points, braze points, weld points, etc.)
between the peaks 72 and valleys 74 of the inserts 66 and the
interior sides of the tubes 26. In some embodiments, the wavy
cross-section of the insert 66 may extend only a portion of a
length L of the insert 66. For example, the wavy cross-section may
be provided at the ends of the insert 66 where the tube 26 is
connected to a header 18, 20, or alternatively where the tube 26
and/or insert 66 experiences the most thermal and mechanical
stress.
[0045] As shown in FIGS. 2, 4, and 5, at least one structural
deficiency 78 can be formed along at least one of the flanks 76 of
an insert 66. In some embodiments, the structural deficiency 78 can
include a groove extending along the entire length L or
substantially the entire length L of a flank 76 between opposite
ends 80 of the insert 66. In other embodiments, the groove 78 can
extend along less than the entire length L of the flank 76 (e.g., a
groove 78 can be staggered along the length L of a flank 76). In
some embodiments, the structural deficiency 78 may extend only a
portion of a length L of the insert 66. For example, a groove 78
may be provided at the ends of the insert 66 where the tube 26 is
connected to a header 18, 20, or where the tube 26 and or insert 66
experiences the most thermal and mechanical stress. In some
embodiments, a groove 78 or other structural deficiency 78, can be
formed in opposing sides of the insert 66 to further weaken the
insert at a particular location on the flank 76.
[0046] Structural deficiencies 78 can take various forms and
shapes, and can be provided on the inserts 66 in various manners
including scoring, stamping, etching, and the like. In some
embodiments, groove 78 has a cross-section that is V-shaped,
U-shaped, rectangular, or irregular. Structural deficiencies 78 can
be formed in the insert 66 prior to or after folding or cutting of
the insert 66.
[0047] In embodiments, such as the illustrated embodiment of FIGS.
1-5, having grooves 78, failures and/or cracking of the inserts 66
caused by expansion and contraction of the inserts 66 will occur
along the grooves 78 where the inserts 66 are weakest. In these
embodiments, the grooves 78 are positioned at locations on the
inserts 66 where cracks and/or failures are anticipated to cause
the least damage to the structural integrity of the inserts 66
and/or where cracks or failures are anticipated to have a minimal
affect on the heat transfer characteristics of the heat exchanger
10.
[0048] As shown in FIGS. 2, 4, and 5, the grooves 78 can be located
midway along the height H of the flanks 76 so that the grooves 78
are spaced a maximum distance from the peaks 72, valleys 74, and
corresponding connection points of the inserts 66. Thus, structural
failures (i.e., cracking, buckling, etc. of the insert 66) will be
spaced a maximum distance from the connection points (e.g., solder
points, braze points, weld points, etc.) between the peaks 72 and
valleys 74 of the inserts 66 and the interior sides of the tubes
26. This enables the insert 66 to provide sufficient structural
support to the tube 26 and simultaneously maximize the heat
transfer between the first and second fluids despite a structural
failure of the insert 66 as is described in more detail below.
[0049] In embodiments, such as the illustrated embodiment of FIGS.
1-5, in which grooves 78 are located along the flanks 76 of the
inserts 66, any cracks or failures occur at or near a midpoint of
the height H of the flanks 76 and at a maximum distance from the
connection points (e.g., solder points, braze points, weld points,
etc.) between the peaks 72 and valleys 74 of the inserts 66 and the
interior sides of the tubes 26. In these embodiments, even after
cracking or failure of the flanks 76, the height H of the flanks 76
is approximately equal to 1/2 of the original height H of the
flanks 76 prior to cracking or failure of the flanks 76.
Alternatively or in addition, even after cracking or failure of the
flanks 76, the peaks 72 and valleys 74 of the inserts 66 remain
connected to the interior sides (e.g., the upper and lower interior
sides in the illustrated embodiment of FIGS. 1-5) of the tubes 26.
In this manner, the inserts 66 remain connected to the tubes 26 and
continue to provide a maximum structural support to the tubes 26,
even after cracking or failure of the flanks 76.
[0050] More particularly, it has been found that for corrugated
inserts 66, such as, for example, the inserts 66 of the illustrated
embodiment of FIGS. 1-5, the stiffness of an insert 66 can be
calculated using the equation 1/12*(insert thickness T)*(insert
height H).sup.3. Accordingly, in embodiments, such as the
illustrated embodiment of FIGS. 1-5, in which cracking and failures
occur at the grooves 78, which are spaced a maximum distance from
the peaks 72 and valleys 74 of the inserts 66 and which are spaced
a maximum distance from the connection points (e.g., solder points,
braze points, weld points, etc.) between the peaks 72 and valleys
74, the height H of each of the flanks 76, even after cracking or
failure, is maximized. In this manner, each of the flanks 76 can
maintain a maximum possible stiffness, even after failure or
cracking.
[0051] FIGS. 6 and 7 illustrate an alternate embodiment of a heat
exchanger 210 according to the present invention. The heat
exchanger 210 shown in FIGS. 6 and 7 is similar in many ways to the
illustrated embodiments of FIGS. 1-5 described above. Accordingly,
with the exception of mutually inconsistent features and elements
between the embodiment of FIGS. 6 and 7 and the embodiments of
FIGS. 1-5, reference is hereby made to the description above
accompanying the embodiments of FIGS. 1-5 for a more complete
description of the features and elements (and the alternatives to
the features and elements) of the embodiment of FIGS. 6 and 7.
Features and elements in the embodiment of FIGS. 6 and 7
corresponding to features and elements in the embodiments of FIGS.
1-5 are numbered in the 200 series.
[0052] In the illustrated embodiment of FIGS. 6 and 7, the tubes
226 of the heat exchanger 210 support inserts 266 having a series
of alternating peaks 272 and valleys 274. As also shown in FIGS. 6
and 7, the peaks 272 and valleys 274 can engage respective upper
and lower interior sides of a tube 226. Flanks 276 can extend in a
generally vertical direction in the illustrated embodiment of FIGS.
6 and 7 between adjacent peaks 272 and valleys 274.
[0053] As shown in FIGS. 6 and 7, the flanks 276 can extend in a
generally linear direction between upper and lower interior sides
of the tubes 226 and can be substantially perpendicular to the
upper and lower interior sides of the tubes 226. In other
embodiments, the inserts 266 can have other shapes and
configurations.
[0054] Grooves 278 can be formed along at least some of the flanks
276 of the inserts 266. The grooves 278 can take various forms and
shapes, and can be provided on the inserts 266 in various manners
including scoring, stamping, bending, and the like. As shown in
FIGS. 6 and 7, the grooves 278 can be positioned at locations on
the inserts 266 where cracks and/or failures are anticipated to
cause the least damage to the structural integrity of the inserts
266 and/or where cracking or failures are anticipated to have a
minimal affect on the heat transfer characteristics of the heat
exchanger 210.
[0055] As shown in FIGS. 6 and 7, the grooves 278 can be located
midway along the height H of the flanks 276 so that the grooves 278
are spaced a maximum distance from the peaks 272 and valleys 274 of
the inserts 266 and so that the grooves 278 are spaced a maximum
distance from the connection points (e.g., solder points, braze
points, weld points, etc.) between the peaks 272 and valleys 274 of
the inserts 266 and the interior sides of the tubes 226.
[0056] The embodiments described above and illustrated in the
figures are presented by way of example only and are not intended
as a limitation upon the concepts and principles of the present
invention. As such, it will be appreciated by one having ordinary
skill in the art that various changes in the elements and their
configuration and arrangement are possible without departing from
the spirit and scope of the present invention.
* * * * *