Note: Descriptions are shown in the official language in which they were submitted.
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
STACKED PLATE HEAT EXCHANGER
BACKGROUND OF THE INVENTION
This invention relates to heat exchangers, and in particular to heat
exchangers made up of stacked plate pairs defining flow passages
therebetween.
As well known in the art, vehicle fuel systems, for example those used
in diesel passenger vehicles, often require a fuel to air cooler to cool
excess
fuel that is returned to the fuel tank from the fuel system. Due to limited
space
and high ambient temperatures, it is generally not practical to locate a fuel
cooler in the engine compartment of a vehicle. Instead, it is often possible
to
locate the fuel cooler in an external location under the body of the vehicle.
For
example in a passenger vehicle, the fuel cooler may be located under the
floor pan.
Generally, there is very limited space to put an underbody mounted
cooler in. For example, in a passenger vehicle, the entire available space for
an under-the-floor-pan cooler may be a height of about 35 mm, a length of 1-2
meters and a width of about 120mm. Thus, it is important for an underbody
cooler to be compact and have high heat exchange efficiency. Additionally, as
an underbody cooler is exposed to debris and other objects, it must be very
durable.
Current under-body fuel coolers generally fall into two categories,
namely serpentine tube on plate coolers and extrusion type coolers.
Serpentine tube on plate coolers consist of a serpentine tube bonded (brazed)
to an aluminum plate. The plate may have lanced louvers, which serve to
interrupt the air flow boundary layer. Extrusion type coolers include an
aluminum finned-portion that is co-extruded with an adjacent flow channel
portion. After extrusion, the flow channel portion is closed off at opposite
ends
and inlet and outlet fittings provided. Underbody mounted fuel coolers
typically
have low fuel mass flow velocities and speed dependent air mass flows, and
are - in terms of heat transfer - typically "airside limited". Extrusion-type
coolers typically suffer from limited air flow mixing (i.e. disrupting the
airside
CA 02485987 2010-08-16
heat transfer boundary layer). Serpentine tube on plate coolers typically
suffer
from limited air flow mixing and a relatively low airside heat transfer area.
In addition to extrusion-type and serpentine tube on plate coolers, an
alternative form of heat exchanger is the stacked plate-pair heat exchanger as
is shown, for example, in U.S. patent No. 5,692,559 issued December 2,
1997, and assigned to the assignee of the present invention. Stacked plate
pair heat exchangers are typically cost efficient to manufacture and have been
widely adopted for applications such as oil coolers. However, existing
stacked-plate pair heat exchangers have generally not been configured for
use as under-body heat exchangers.
It is therefore desirable to provide a stacked plate pair heat exchanger
that is configured for use as an underbody cooler and which provides
improved air-flow mixing and heat transfer area.
According to one aspect of the invention there is provided a stacked
plate heat exchanger including a plurality of stacked plate pairs, each plate
pair including first and second plates having elongate central portions
surrounded by sealably joined edge portions with an elongate fluid passage
defined between the central portions. Each plate pair has spaced apart inlet
and outlet openings in flow communication with the fluid passage, at least
some of the plate pairs having a substantially planar fin plate extending
peripherally outward from the joined edge portions. The fin plates of the
stacked plate pairs are spaced apart and substantially parallel to each other.
For each of the at least some plate pairs, the planar fin plate has a first
fin end
and a second fin end and first and second spaced apart elongate edges
extending therebetween. The fluid passage is located between the spaced-
apart edges and has a first fluid passage end located closer to the first fin
end
than the second fin end and a second fluid passage end is located closer to
the second fin end than the first fin end. The fluid passage is oriented at an
angle relative to the first elongate edge of the fin plate with one of the
first and
second fluid passage ends being located closer to the first elongate edge than
the other of the first and second fluid passage ends. The fluid passages of
the
plate pairs are all oriented in a common direction.
2
CA 02485987 2010-08-16
According to another embodiment of the stacked plate heat exchanger
of the invention, the heat exchanger comprises a plurality of stacked plate
pairs with each pair including first and second plates having elongate central
portions surrounded by sealably joined edge portions with an elongate fluid
passage defined between the central portions. Each plate pair has spaced
apart inlet and outlet openings and fluid communication with the fluid
passage. At least some of the plate pairs have a substantially planar fin
plate
extending peripherally outward from the joined edge portions. The fin plates
of
the stack plate pairs are spaced apart and substantially parallel to each
other.
The central portions are substantially planar and have a first plurality of
obliquely oriented parallel ribs formed thereon. The ribs of the first and
second
plates in each plate pair cooperate to form at least a portion of fluid
passages
in back-to-back plates of adjacent plate pairs. For each plate pair having a
fin
plate, the plate pair has elongate, parallel, spaced-apart first and second
edges. The fluid passage is located between the spaced apart first and
second edges and extends at an angle that is non-parallel to the first and
second edges. The ribs on at least one of the first and second plates are
oriented to be close to parallel to the first and second edges.
According to yet another embodiment of the present invention, a
stacked plate heat exchanger comprises a plurality of stacked plate pairs,
each plate pair including first and second plates having elongate central
portions surrounded by sealably joined edge portions with an elongate fluid
passage defined between the central portions. Each plate pair has spaced-
apart inlet and outlet openings in flow communication with the fluid passage.
At least some of the plate pairs have a substantially planar fin plate
extending
periphery outward from the joined edge portions. The fin plates of the stacked
plate pairs are spaced apart and substantially parallel to each other. For at
least some plate pairs having fin plates, the first plate includes a laterally
extending flange around an outer edge of the edge portion thereof. The edge
portion of the second plate is nested within the laterally extending flange.
The
fin plate extends outwardly from an edge of the laterally extending flange.
3
CA 02485987 2010-08-16
According to a further embodiment of the invention, a stacked plate
heat exchanger comprises a plurality of stacked plate pairs, each plate pair
including first and second plates having an elongate central portions
surrounded by sealably joined edge portions with an elongate fluid passage
defined between the central portions. Each plate pair has spaced apart inlet
and outlet openings in fluid communication with the fluid passage. At least
some of the plate pairs have a substantially planar fin plate extending
peripherally outward from the joined edge portions. The fin plates of the
stacked plate pairs are spaced apart and substantially parallel to each other.
The central portions are substantially planar and have a first plurality of
obliquely oriented, parallel ribs formed thereon. The ribs of the first and
second plates in each plate pair cooperate to form at least a portion of the
fluid passage in back-to-back plates of adjacent plate pairs and the ribs of
the
back-to-back plates are parallel and in contact along a length thereof.
Example embodiments of the invention will now be described, by way
of example, with reference to the accompanying drawings throughout which
like reference numerals are used to refer to similar elements and features, in
which:
Figure 1 is a side elevation of a stacked plate heat exchanger
according to one embodiment of the invention;
Figure 2 is a top plan view of the heat exchanger of Figure 1;
Figure 3 is a diagrammatic view of a passenger vehicle with the heat
exchanger of Figure 1 mounted thereto;
Figure 4 is a side elevation of a first plate of each plate pair according
to one embodiment of the invention and Figure 4a is a partial sectional view
taken along the lines lVa-lVa of Figure 4;
Figure 5 is a side elevation of a second plate of each plate pair;
Figure 6 is an enlarged sectional side view of a portion of a plate pair
showing the crossing of ribs on mating plates, taken along the lines VI-VI of
Figure 2;
3a
CA 02485987 2010-08-16
Figure 7 is a sectional view of a plate pair taken along the lines VII-VII
of Figure 6 and Figure 7A is an enlarged portion of a circled part of Figure
7;
Figure 8 shows a simplified top plan view of two adjacent plate pairs;
Figures 9 and 10 shows simplified side views of each of the plates of
Figure 8 demonstrating two alternative embodiments of the invention;
Figure 11 is a further diagrammatic view of the heat exchanger located
under the body of a vehicle.
Figure 12 is a simplified side view of a plate pair in accordance with a
further embodiment of the invention.
15
25
3b
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
Figure 13 is a side view of a further plate pair configuration in
accordance with another embodiment of the invention.
Figure 14 shows two of the plate pairs of Figure 13 joined together;
Figure 15 is a sectional view taken along the lines XV-XV of Figure 13;
Figure 16 is a sectional view taken along the lines XVI-XVI of Figure
13;
Figure 17 is a sectional view of a further possible plate pair
configuration;
Figure 18 is a side view of still a further plate pair configuration in
accordance with embodiments of the present invention;
Figure 19 is a sectional view taken along the lines XIX-XIX of Figure
18;
Figure 20 is a sectional view taken along lines XX-XX of Figure 20;
Figure 21 is a perspective view of a further plate pair configuration
according to embodiments of the invention;
Figure 22 is a partial side view of the plate pair of Figure 21;
Figure 23 is an enlarged partial perspective view of the plate pair of
Figure 21;
Figure 24 is a top plan view of a heat exchanger according to yet
another embodiment of the invention; and
Figure 25 is,a side view of a plate pair of the heat exchanger of Figure
24.
DESCRIPTION OF THE EXAMPLE EMBODIMENTS
Referring firstly to Figures 1 and 2, an example embodiment of a heat
exchanger according to the present invention is indicated generally by
reference numeral 10. Heat exchanger 10 is formed from a plurality of stacked
plate pairs 12, that are sandwiched between first and second end support
plates 14, 16. The first and second end support plates 14, 16 each have front
4
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
and back horizontal mounting flanges 18, 20, each of which has one or more
mounting holes 22 formed there through for mounting heat exchanger 10 in a
desired location. First and second end support plates are not essential to
heat
exchanger 10 and may be eliminated, altered or replaced with other suitable
arrangements for mounting the heat exchanger 10.
In an automotive application, the heat exchanger 10 will typically be
used as an underbody cooler. In one application, the heat exchanger may be
used to cool excess fuel that is returning from the fuel system to the fuel
tank,
however, it could also be used in other applications to cool other types of
fluids. Figure 3 shows a diagrammatic view of heat exchanger 10 mounted
under the floor pan of an automobile 24. When the heat exchanger 10 is
mounted in place, inlet fitting 26 and outlet fitting 28 (see Figures 1 and 2)
are
connected to a fuel return line (not shown) in the fuel system such that the
returning fuel passes through the heat exchanger 10.
Referring now to Figures 1, 2 and 4 to 7 the construction of plate pairs
12 will now be described in greater detail. Figures 4 and 5 show,
respectively,
example embodiments of the first and second plates that make up each plate
pair 12. The first plate 30 includes an elongate central planar portion 34
that is
surrounded by a planar edge portion 36, which in turn is surrounded by a
peripherally extending, substantially planar fin plate portion 38. A series of
ribs
40 are formed along central planar portion 34. In the presently described
embodiment, the ribs 40 closer the front end 37 of the first plate 30 are
parallel and obliquely orientated in a first direction, and the ribs 40 closer
the
back end 39 of the plate 30 are parallel and obliquely orientated in a second,
opposite direction, with a central triangular boss 42 being formed between the
two sets of oppositely orientated ribs 40.
The second plate 32 has a configuration similar to that of first plate 30
in that it includes an elongate central planar portion 44 that is surrounded
by a
peripheral planar edge portion 46, with series of ribs 48 formed along central
planar portion 44, however, in the presently described embodiment, the
second plate 32 does not include a fin plate portion. As with first plate 30,
the
ribs 48 closer the front end 50 of the second plate 32 are parallel and
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
obliquely orientated in one direction and the ribs 48 closer the back end 52
of
the plate 32 are parallel and obliquely orientated in an opposite direction,
with
a central triangular boss 50 being formed between the two sets of oppositely
orientated ribs 48.
In Figure 4, the first plate 30 is viewed showing its outer surface, so
that ribs 40 and triangular boss 42 are coming out of the page. In Figure 5,
the
second plate 32 is viewed showing its inside surface, so that the ribs 48 and
boss 50 are actually going into the page. First and second plates 30 and 32
are placed together and sealably connected about edge portions 36, 46 to
form a plate pair 12 (As best seen in Figures 6 and 7), in which a fluid
passage 62 is defined between planar central portions 34, 44 of the plates 30,
32. More particularly, and as will be described in greater detail below, in
the
presently described embodiment overlapping ribs 40, 48 provides fluid
passage 62 that extends from an inlet end to an outlet end of the plate pair
12.
In an example embodiment the plates 30,32 are stamped from braze-
clad aluminum or aluminum alloy, however other suitable metallic and non-
metallic materials formed using various methods such as stamping, roll-
forming, etc. could be used as desired for specific heat exchanger
applications.
In one example embodiment, the second plate 32 is nested within a
pocket formed in first plate 30, which provides a novel self-locating and self-
aligning function during assembly of each plate pair 12. As best seen in
Figures 7 and 7A, the planar edge portions 36 and 46 each include facing
planar surfaces 66,68 that abut. The planar edge portion 36 of the first plate
30 is slightly larger than the edge portion 46 of the second plate, and
terminates in a peripheral locating wall 64 that extends laterally from the
planar edge portion 36. The planar fin 38 extends outward from the locating
wall 64 in a plane that is parallel to the plane of edge portion 36, such that
the
locating wall 64 provides a step between the edge portion 36 and the planar
fin 38. The locating wall 64 and edge portion 36 thus define a pocket,
indicated generally by reference numeral 65 in Figure 7A, within which the
6
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
edge 46 of the second plate 32 is nested. As noted above, preferably, the
first
plate edge portion 36 is slightly larger than the second plate edge portion
46,
with the result that locating wall 64 will be spaced slightly apart from
second
plate edge 46, allowing brazing material to provide a secure joint in the
space
70. Additionally, space 70 permits the second plate 32 to be compressed
somewhat against first plate 30 during assembly of the heat exchanger plate
pair stack such that the plate 32 acts as a leaf spring with the result that
improved sealing reliability is possible during brazing of the plate pair
stack.
As a result of the nesting plate pair structure, the force of compression on
the
plate pairs by the assembly fixture is transmitted equally through the entire
plate stack, providing a self-fixturing mechanism that holds the plates in
place
during brazing. Pocket 65 facilitates relative positioning of the plates 30,32
during heat exchanger assembly and maintains the relative positions of the
first and second plates during heat exchanger assembly and brazing,
providing the self-locating and self-aligning features noted above.
Referring again to Figures 4 and 5, first and second plates 30, 32 are
also formed with end bosses 54, 56 which define respective inlet openings 58
and outlet openings 60. When plate pairs 12 are stacked, all of the inlet
openings 58 are in registration and communicate with inlet fitting 26, and all
of
the outlet openings 60 are in registration and communicate with outlet fitting
28. In this way, all of the end bosses 54 form an inlet manifold and all of
the
end bosses 56 form an outlet manifold so that fluid flows in parallel through
all
of the plate pairs 12. However, it will be appreciated that some of the inlet
openings 58 and some of the outlet openings 60 could be selectively closed
or omitted, as will be appreciated by those skilled in the art, so that fluid
could
be made to flow in series through each of the plate pairs 12, or in some
series/parallel multi-pass combination. In a multi-pass configuration, inlet
and
outlet fittings may be connected to the same manifold.
As shown in Figure 5, the opposite ends 50, 52 of the second plate 32
may conveniently be shaped differently (end 50 having square corners and
end 52 having rounded corners). The ends of the pocket of first plate 30 in
which the second plate is received have corresponding shapes, such that the
7
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
edge of the second plate can only be received within the pocket when
properly orientated, in order to prevent incorrect assembly of the plate
pairs.
Figure 6 shows a portion of a plate pair 12, with the second plate 32
being located behind the first plate 30 and thus hidden from view. The ribs 48
of the second plate 32 are shown in phantom with dashed lines. The second
plate ribs 48 cooperate with the first plate ribs 40 to define fluid passage
62
having a zigzag pattern, indicated by phantom arrows 72, along the length of
the plate pair 12. With reference to Figure 1, the fluid passage 62 of a plate
pair 12 is generally indicated, along with the zigzag path 72 that defines the
fluid path. The use of cooperating ribs formed on the plates of a plate pair
to
provide fuel mixing along a fluid passage is well known, as is apparent from
previously mentioned U.S. Patent no. 5,692,559, and a number of different
criss-cross rib configurations are possible other that shown in Figures 4 to 6
of
the present application. By way of example, each rib could communicate with
three ribs on the opposing plate instead of just two as illustrated. Further,
in
some embodiments, the orientation of the ribs may not change at the plate
pair mid point, but rather all ribs the entire length of the plate may be
parallel.
Thus, the exact criss-cross rib pattern used in the plate pairs of the heat
exchanger 10 need not be as illustrated, and suitable alternative
arrangements could be used.
When the plate pairs 12 are arranged in parallel in a stack, the ribs
from adjacent plate pairs are brazed in contact with each other, providing
strength and rigidity to the stack of plate pairs 12. Abutting ribs 40, 48
between adjacent plate pairs 12 are shown on the first two plate pairs 12 at
the top of Figure 2. Although not shown in detail in Figure 2, it will be
appreciated that the abutting ribs between adjacent plate pairs continues
throughout the entire stack of plate pairs. Air ducts or passages 74 are
formed
between the abutting ribs 40, 48 of adjacent plate pairs such that air can
flow
between adjacent plate pairs thus facilitating heat exchange between the air
and with the fluid flowing in the fluid passages 62 defined within each plate
pair 12. If identical plate pairs 12 are used throughout the plate pair stack,
then the contacts between abutting ribs of adjacent plate pairs will be non-
8
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
continuous, and, in the illustrated example each rib will contact two ribs on
an
adjacent plate. Alternatively, in a further example embodiment of the
invention, the pattern on adjacent plate pairs is reversed such that each rib
contacts the rib of an adjacent plate along the entire length of the rib. In
one
example embodiment, this alternative embodiment is achieved by rotating
alternative plate pairs end for end one hundred and eighty degrees.
By way of further explanation, reference is made to Figures 8 to 10.
Figure 8 shows a simplified top plan view of two adjacent plate pairs 12A and
12B, formed from plates 32A, 30A and 32B, 30B, respectively. Although not
shown in Figure 8, contacting ribs 48, 40 and air passages 74 are located
between plate pairs 12A and 12B. Figure 9 shows simplified side views of
each of the plates taken from a viewing direction indicated by arrow 76
showing the orientation of ribs 40 and 48 in an embodiment of the invention in
which each of the plate pairs are identically orientated. Figure 10 is similar
to
Figure 9, except that it shows an embodiment in which the plates in adjacent
pairs are rotated 180 degrees such that rib orientation is reversed between
the adjacent plate pairs. In the embodiment of Figure 9, the ribs 40 of plate
30A (such ribs 40 extend outward from the page as illustrated) abut against
the ribs 48 of plate 32B (such ribs 48 extend inward into the page as
illustrated). The ribs abut in a non-continuous manner, defining a series of
air
passages between the plate pairs 12A and 12B. In the embodiment of Figure
10, the ribs 40 of plate 30A also abut against the ribs 48 of plate 32B.
However, unlike in Figure 9, the abutting ribs of the adjacent plate pairs are
similarly orientated such that each rib 40 abuts continuously along its length
with a corresponding rib 48. The embodiment of Figure 10 provides larger
direct air-flow passages between the plate pairs than the embodiment of
Figure 9.
The peripherally extending fin plate portion 38 of each plate pair 12
provides an increased heat exchange surface area over previous plate pair
heat exchangers not having such a fin 38. The fin 38 extends "air-side" from
the opposed central plate portions 34, 44 of the plates between which the
fluid
passage 62 is defined. With reference to Figure 1, in an example embodiment
9
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
when the heat exchanger is moving in a direction indicated by arrow 80, air
flows into and through the parallel fins 38 and through the air passages 74
between the ribbed plate portions, as indicated by air flow arrows 78, drawing
heat away from the fluid passing through fluid passages 62. In the presently
described embodiment, the heat exchanger plate pairs 12 are configured such
the ribbed portions there of are angled relative to the direction of travel.
In
particular, as can be appreciated from Figure 1, the plate pairs 12 are
arranged such that the fluid passages 62 have a leading end that is lower
than a trailing end thereof. As can be seen in Figure 4, in an example
embodiment, the rectangular fin plate portion 38 is sized to take advantage of
the angled configuration, the fin plate portion 38 extending a greater height
H1
from a forward end of the ribbed central portion 34 of the first plate 30 and
a
lesser height H2 from a rearward end of central portion 34. In other words, as
can be appreciated from Figure 4, the fin plate portion 38 has longitudinal
upper and lower peripheral edges 134, 136 that extend length-wise between
ends 37, 39. The portion of the plate pair (in particular the elongate central
portions 34,44) that define the fluid passage 62 extends the majority of the
distance between ends 37,39, but at an angle relative to the edges of the fin
plate, rather than parallel to the fin plate edges.
With reference again to Figure 4, protrusions or dimples 84 and 86 may
conveniently be formed in the fin plate portion 38 of the first plate 30 for
the
purpose of strengthening the extending fin portions and also to disrupt the
boundary layer of air passing between the fins. In the illustrated embodiment,
a first pair of dimples 84, 86 are provided near the lower back end 39 of the
plate 30. As can be seen in Figure 4A, the dimples 84 and 86 extend in
opposite directions. A second pair of dimples 84, 86 are provided near the
upper front end 37 of the plate 30. The dimples 84, 86 at the front end 37
extend in directions that are opposite of their counterparts at back end 39
such that when the plate 30 is rotated by 180 degrees in alternating plate
pairs 12, the dimples 84, 86 of one plate pair 12 will abut against and be
brazed to the dimples 84, 86, respectively, of an adjacent plate pair, as can
be
seen in Figure 2.
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
With reference to Figure 11, the angled orientation of the plate pairs
will be discussed in greater detail. Figure 11 shows a diagrammatic view of
heat exchanger 10 located under the body of vehicle 24. The height H
represents the distance from ground 82 to the underside of vehicle 24, and
the height a is a specified clearance between the underbody and the heat
exchanger 10. The height H-b is the clearance required between ground and
any part of the vehicle, with b-a being the available height for heat
exchanger
10. As indicated in Figure 11, the air velocity profile is approximately
linear in
the y direction from the underbody to the ground. For optimum air-side heat
transfer, it is desired to place the cooler in the fastest flowing air. The
inclination angle a refers to the angle between the general direction of fluid
passages 62 relative to the horizontal. For maximum air flow through the
cooler, a=90 degrees, however such angle is not possible for any heat
exchanger in which the length L>b-a. The inclination angle a can be greater or
less than 0, with a positive angle occurring when the leading edge of the flow
passages of the heat exchanger is higher than the trailing edge, and a
negative angle occurring when the trailing edge of the flow passages of the
heat exchanger is higher than the leading edge (as is shown in Figure 11). A
negative a can create a high pressure air zone between the heat exchanger
and the car underbody due to the narrowing passage there between, forcing
air through the trailing half of the heat exchanger as indicated by arrow 78
in
Figure 11. In some applications, the heat exchanger could be orientated
leading edge up with a positive a. The angle a is preferably selected to
maximize air flow through the heat exchanger dependent on the dimensional
restraints that are placed on the heat exchanger by its intended use. The use
of plate pairs having fin plates that are angled relative to the fluid
passages
therethrough allows the size of the fin plates to be relatively large relative
to
the space permitted for the heat exchanger package.
Figure 12 shows a further plate pair 92 for use in an alternative
embodiment of heat exchanger 10. The plate pair 92 is substantially identical
to plate pair 12, except that ribs 40 in first plate 30 are all parallel along
the
entire length of plate 30, without a change in orientation at the mid-point of
the
plate. Similarly, ribs 48 (shown in phantom) of second plate 32 are all
parallel.
11
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
The angle A of ribs 40 relative to the horizontal is relatively small so that
the
ribs 40 are close to being parallel with the incoming air flow direction 78.
Such
configuration may provide improved heat transfer in some applications. The
plate pair 92 may also include a trailing fin plate portion 90 on which is
formed
a plurality of dimples 88. In the view of Figure 12, some dimples 88 may
extend into the page, and some may protrude from the page. The dimples 88
serve to further break up the air flow boundary layer of air passing through
the
heat exchanger.
Figures 13 to 16 illustrate a further plate pair 94 for use in yet another
embodiment of heat exchanger 10. The plate pair 94 is similar to plate pair
12,
with the exception of differences that will be appreciated from the following
description. The plate pair 94 is conveniently formed from two similar
opposed plates 96A and 96B that may be mirror images of each other. Each
plate 96A and 96B has peripheral edge portions 100, the edge portions 100 of
two plates joined together to form plate pair 94. Each plate 96A and 96B also
has a central planar portion 102, the central portions of the joined plates in
each plate pair 94 being spaced apart to define a fluid passage 104 between
the plates. The central planar portions 102 are not ribbed as in plate pair
12,
but rather an elongate turbulizer 106 is located in the fluid passage 104 for
augmenting fluid flow therethrough (in some applications, the channel 104
could be clear with no turbulizer located therein). The peripheral edge
portions
100 extend a relatively large distance from the central planar portions 102,
thus providing an integrally formed'air-side fin surface portion for plate
pair 94.
As with plates of plate pair 12, the plates 96 are formed with end bosses 54,
56 that define respective inlet and outlet openings 58, 60. Figure 14 shows
two plate pairs 94 arranged side-by-side as part of a plate pair stack of a
heat
exchanger, with an air passage 108 defined between the plate pairs 94.
In order to facilitate assembly of the plate pairs 94, locating protrusions
or half dimples 110, 112 may be provided along the perimeter edge of the
plates 96A, 96B to assist in lining up the plates in a plate pair. As shown in
Figure 13, at air-flow downstream end 78, the half dimple 112 projects
outward from the page, and the half dimple 110 projects into the page, and
12
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
conversely at air-flow upstream end 116, the half dimple 112 projects into the
page, and the half dimple 110 projects out of the page. Plates 96A, 96B are
mated together as shown in Figure 15 with locating dimples aligned and
nested as shown in Figure 16.
Figure 17 shows yet another possible plate pair configuration for plate
pair 94. In the embodiment of Figure 17, the upper fin plate portion 100
extends only from one plate 96A of the plate pair, and the lower fin plate
portion 100 extends only from the other plate 96B of the plate pair 94. In the
embodiment of Figure 17, the edge portions 128 and 130 of opposed plates
96A, 96B are joined to form plate pair 128. In each plate 96A,96B, the fin
plate portion 100 extends peripherally from the edge portion 130, and in
particular is joined to the edge portion 130 by a locating wall 132 that is
perpendicular to the edge portion 130 and fin plate portion 100. The locating
wall 132 and edge portion 130 of one plate 96A, 96B form a notch for
receiving the edge portion 128 of the other plate of the plate pair 128, and
vice versa.
In some embodiments, ribs (not shown) that extend only partially into
fluid passage 104 may be provided on central portions 102 in order to
augment fluid flow through fluid passage 104.
Figures 18, 19 and 20 show another possible plate pair configuration,
indicated generally by reference 130, for use in heat exchanger 10. The plate
pair 130 is substantially similar to plate pair 12, with one notable
difference
being that dimples 132,134 (rather than ribs) are formed in the spaced apart
central planar portions 34, 44 of plates 30, 32 to augment flow through fluid
passage 62. In the illustrated embodiment a central row of dimples 132
extend inward into the fluid passage 62, with the inner ends of opposing
dimples 132 joining together. Two parallel rows of outwardly (i.e. air-side)
extending dimples 134 are provided along the fluid passage 62. Preferably,
the extending dimples 134 from one plate pair 130 will contact the extending
dimples 134 from an adjacent plate pair, thus providing rigidity to the core
stack as well as providing flow augmentation means for breaking the
boundary layer of air flowing between the plate pairs. As with plate pair 12,
13
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
the plate pair 130 is configured such that the fluid passage defined between
central planar portions 34, 44 is angled relative to the rectangular fin
portion
38 of the plate pair.
Figures 21 to 23 show another possible plate pair configuration,
indicated generally by 150, for use in heat exchanger 10. The plate pair 150
is
substantially similar in construction to plate pairs 12 and 130, but for
differences that will be apparent from the Figures and the present
description.
In plate pair 150, delta shaped winglets 152 are formed along leading upper
and trailing lower parts of the air side fin plate portion 38 of the plate 30
to
provide enhanced air-side heat transfer by inducing swirl and boundary layer
separation and recreation along the length of the fin plate portion. In some
embodiments, winglets 152 are selectively located only near the leading end
of the heat exchanger; and in some embodiments winglets 152 are selectively
located only near the trailing end of the heat exchanger, depending on the
desired heat exchanger performance. The presence of winglets 152 causes
air swirl to be induced in the air flow downstream therefrom, resulting in
downwash air flow impacting on the fin plate portion that can improve local
air
side heat transfer. In one example winglet configuration as shown in Figure
22, a leading winglet 152 (relative to the direction of air flow as indicated
by
arrow 154 in Figure 22) located on an upper portion of fin plate portion 38 is
followed by two spaced apart pairs of trailing winglets 152. In each winglet
pair, the trailing winglet is closely placed to the leading winglet and at a
relative angle to the leading winglet, such that the two winglets act in
complimentary fashion for inducing air-side swirl. The delta (triangular)
shaped winglets 152 are, in the example embodiment, lanced along two side
edges from the fin plate portion 38 and folded out from the plate. In an
example embodiment, as best seen in Figure 23, each winglet 152 has an
aspect ratio of I/h=2; an angle of attack of a=45 to oncoming air flow (in
the
X-Y plane as shown in Figures 21-23); and is folded out from the fin plate
portion 38 at X =90 (in the x-z plane) to project a maximum surface area into
the oncoming air flow. Within each winglet pair, the winglet spacing is equal
to
h. Other winglet configurations and shapes are used in various embodiments.
14
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
In the illustrated embodiment of Figures 21-23, the central planar
portions of the plates of heat exchanger plate pair 150 have dimples 156, 158
formed therein. Dimples 156 protrude outward from the plates, such that the
dimples 156 from back-to-back plates of adjacent plate pairs contact each
other on the air-side passages between adjacent plate pairs. The dimples 158
extend inward into the internal flow channels 62 defined within the plate
pair,
turbulizing fluid flow therein and providing structural strength. In plate
pair
150, the flow channel 62 is wider near the inlet and outlet openings 58, 60,
and narrower in the region between the openings, to increase the relative
velocity of fluid through the flow channel 62.
Figure 24 shows a further heat exchanger 160 according to yet another
example embodiment, and Figure 25 shows a plate pair of heat exchanger
160. Heat exchanger 160 is substantially similar in construction to heat
exchanger 10, but for the differences that will be apparent from the Figures
and the present description. In heat exchanger 160, external fin plates 166,
which in the illustrated embodiment are corrugated fin plates, are located in
the air passages 168 between back-to-back plates 30, 32 of adjacent plate
pairs 162. In plate pairs 162, the central planar portions 34, 44 of plates
30,
32, respectively, are formed with spaced apart dimples 158 that extend inward
into the fluid passage 62. The fin plates 166 are secured between the central
planar portions 34, 44 of the plates 30, 32 of adjacent plate pairs 162 and
the
central planar portion 44. Dashed line 166 in Figure 25 illustrates the
location
of a fin plate 166 relative to the flow passage 62. In an example embodiment,
the fin plate 166 is sized to correspond in height and length substantially to
the size of central planar portions 34, 44 (and hence flow passage 62). Fin
plate 166 can provide air-side heat exchanger surface area and structural
rigidity to the heat exchanger 160. The extended fin plate portion 38 provides
protection for the fin plate 166 from debris. Fin plate 166 can be replaced
with other turbulizing structures, including, for example, an expanded metal
turbulizer plate.
In heat exchanger 160, a flow circuiting insert 164 is provided to divide
the manifold at the leading end of the heat exchanger 160 into two halves,
CA 02485987 2004-11-15
WO 03/102482 PCT/CA03/00839
with inlet and outlet fittings 26, 28. both being located at a leading end of
the
heat exchanger. Brackets 16 and 18 seal off the openings 60 at the trailing
end in the plates 30 and 32 at the outer sides of the heat exchanger 160.
It will be apparent to those skilled in the art that in light of the foregoing
disclosure, many alterations and modifications are possible in the practice of
this invention without departing from the spirit or scope thereof.
Accordingly,
the scope of the invention is to be construed in accordance with the
substance defined in the following claims.
16
