Note: Descriptions are shown in the official language in which they were submitted.
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1
SELF-ENCLOSING HEAT EXCHANGER
WITH CRIMPED TURBULIZER
This invention relates to heat exchangers of the type formed of stacked
plates, wherein the plates have raised peripheral flanges that co-operate to
form
an enclosure for the passage of heat exchange fluids between the plates.
The most common kind of plate type heat exchangers produced in the past
have been made of spaced-apart stacked pairs of plates where the plate pairs
define internal flow passages therein. Expanded metal turbulizers are often
located in the internal flow passages to increase turbulence and heat transfer
efficiency. The plates normally have inlet and outlet openings that are
aligned in
the stacked plate pairs to allow for the flow of one heat exchange fluid
through
all of the plate pairs. A second heat exchange fluid passes between the plate
pairs, and often an enclosure or casing is used to contain the plate pairs and
cause the second heat exchange fluid to pass between the plate pairs.
In order to eliminate the enclosure or casing, it has been proposed to
provide the plates with peripheral flanges that not only close the peripheral
edges
of the plate pairs, but also close the peripheral spaces between the plate
pairs.
One method of doing this is to use plates that have a raised peripheral flange
on
one side of the plate and a raised peripheral ridge on the other side of the
plate.
Examples of this type of heat exchanger are shown in U.S. patent No. 3,240,268
issued to F.D. Armes and U.S. patent No. 4,327,802 issued to Richard P.
Beldam.
A difficulty with the self-enclosing plate-type heat exchangers produced
in the past, however, is that the peripheral flanges and ridges form inherent
peripheral flow channels that act as short-circuits inside and between the
plate
pairs, and this reduces the heat exchange efficiency of these types of heat
exchangers.
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In the present invention, portions of the expanded metal turbulizers are
crimped closed to act as barriers to reduce short-circuit flow and to improve
the
flow distribution between the plates and the overall heat exchange efficiency
of
the heat exchangers.
According to the invention, there is provided a plate type heat exchanger
comprising first and second plates, each plate including a planar central
portion,
a first pair of spaced-apart bosses extending from one side of the planar
central
portion, and a second pair of spaced-apart bosses extending from the opposite
side of the planar central portion. The bosses each have an inner peripheral
edge
portion and an outer peripheral edge portion defining a fluid port. A
continuous
ridge encircles the inner peripheral edge portions of at least the first pair
of
bosses and extends from the planar central portion in the same direction and
equidistantly with the outer peripheral edge portions of the second pair of
bosses. Each plate includes a raised peripheral flange extending from the
planar
central portion in the same direction and equidistantly with the outer
peripheral
edge portions of the first pair of bosses. The first and second plates are
juxtaposed so that one of: the continuous ridges are engaged and the plate
peripheral flanges are engaged; thereby defining a first flow chamber between
the engaged ridges or peripheral flanges, with the fluid ports in one of said
pairs
of spaced-apart bosses forming an inlet and outlet to the first flow chamber,
and
the chamber defining a flow path between the inlet and outlet. The fluid ports
in
the respective first and second pairs of spaced-apart bosses are in
registration.
Also, an expanded metal turbulizer is located between the first and second
plate
planar central portions. The turbulizer includes a crimped portion located in
the flow path to reduce short-circuit flow between the inlet and the outlet.
Preferred embodiments of the invention will now be described, by way of
example, with reference to the accompanying drawings, in which:
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Figure 1 is an exploded perspective view of a first preferred embodiment
of a self-enclosing heat exchanger made in accordance with the present
invention;
Figure 2 is an enlarged elevational view of the assembled heat exchanger
of Figure 1;
Figure 3 is a plan view of the top two plates shown in Figure 1, the top
plate being broken away to show the plate beneath it;
Figure 4 is a vertical sectional view taken along lines 4-4 of Figure 3, but
showing both plates of Figure 3;
Figure 5 is an enlarged perspective view taken along lines 5-5 of Figure 1
showing one of the turbulizers used in the embodiment shown in Figure 1;
Figure 6 is an enlarged scrap view of the portion of Figure 5 indicated by
circle 6 in Figure 5;
Figure 7 is a plan view of the turbulizer shown in Figure 5;
Figure 8 is a perspective view similar to Figure 5, but showing another
embodiment of a turbulizer for use in the present invention;
Figure 9 is a perspective view of the turbulizer of Figure 8 but rotated 180
degrees about the longitudinal axis of the turbulizer;
Figure 10 is a plan view of the turbulizer as shown in Figure 8;
Figure 11 is a plan view of one side of one of the core plates used in the
heat exchanger of Figure 1;
Figure 12 is a plan view of the opposite side of the core plate shown in
Figure 11;
Figure 13 is a vertical sectional view taken along lines 13-13 of Figure
12;
Figure 14 is a vertical sectional view taken along lines 14-14 of Figure
12;
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Figure 15 is a perspective view of the unfolded plates of a plate pair used
to make yet another preferred embodiment of a heat exchanger according to the
present invention;
Figure 16 is a perspective view similar to Figure 15, but showing the
unfolded plates where they would be folded together face-to-face;
Figure 17 is a plan view of yet another preferred embodiment of a plate
used to make a self-enclosing heat exchanger according to the present
invention;
Figure 18 is a plan view of the opposite side of the plate shown in Figure
17;
Figure 19 is a vertical sectional view in along lines 19-19 of Figure 17,
but showing the assembled plates of Figures 17 and 18; and
Figure 20 is a vertical elevational view of the assembled plates of Figures
17 to 19.
Referring firstly to Figures 1 and 2, an exploded perspective view of a
preferred embodiment of a heat exchanger according to the present invention is
generally indicated by reference numeral 10. Heat exchanger 10 includes a top
or end plate 12, a turbulizer plate 14, core plates 16, 18, 20 and 22, another
turbulizer plate 24 and a bottom or end plate 26. Plates 12 through 26 are
shown
arranged vertically in Figure 1, but this is only for the purposes of
illustration.
Heat exchanger 10 can have any orientation desired.
Top end plate 12 is simply a flat plate formed of aluminum having a
thickness of about 1 mm. Plate 12 has openings 28, 30 adjacent to one end
thereof to form an inlet and an outlet for a first heat exchange fluid passing
through heat exchanger 10. The bottom end plate 26 is also a flat aluminum
plate, but plate 26 is thicker than plate 12 because it also acts as a
mounting plate
for heat exchanger 10. Extended corners 32 are provided in plate 26 and have
openings 34 therein to accommodate suitable fasteners (are shown) for the
mounting of heat exchanger 10 in a desired location. End plate 26 has a
thickness typically of about 4 to 6 mm. End plate 26 also has openings 36, 38
to
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form respective inlet and outlet openings for a second heat exchange fluid for
heat exchanger 10. Suitable inlet and outlet fittings or nipples (not shown)
are
attached to the plate inlets and outlets 36 and 38 (and also openings 28 and
30 in
end plate 12) for the supply and return of the heat exchange fluids to heat
5 exchanger 10.
Although it is normally not desirable to have short-circuit or bypass flow
inside the heat exchanger core plates, in some applications, it is desirable
to have
some bypass flow in the flow circuit that includes heat exchanger 10. This
bypass, for example, could be needed to reduce the pressure drop in heat
exchanger 10, or to provide some cold flow bypass between the supply and
return lines to heat exchanger 10. For this purpose, an optional controlled
bypass
groove 39 may be provided between openings 36, 38 to provide some deliberate
bypass flow between the respective inlet and outlet formed by openings 36, 38.
Referring next to Figures 1, 3 and 4, turbulizer plates 14 and 24 will be
described in further detail. Turbulizer plate 14 is identical to turbulizer
plate 24,
but in Figure 1, turbulizer plate 24 has been turned end-for-end or 180 with
respect to turbulizer plate 14, and turbulizer plate 24 has been turned upside
down with respect to turbulizer plate 14. The following description of
turbulizer
plate 14, therefore, also applies to turbulizer plate 24. Turbulizer plate 14
may be
referred to as a shim plate, and it has a central planar portion 40 and a
peripheral
edge portion 42. Undulating passageways 44 are formed in central planar
portion
40 and are located on one side only of central planar portion 40, as seen best
in
Figure 4. This provides turbulizer plate 14 with a flat top surface 45 to
engage
the underside of end plate 12. Openings 46, 48 are located at the respective
ends
of undulating passages 44 to allow fluid to flow longitudinally through the
undulating passageways 44 between top or end plate 12 and turbulizer 14. A
central longitudinal rib 49, which appears as a groove 50 in Figure 3, is
provided
to engage the core plate 16 below it as seen in Figure 1. Turbulizer plate 14
is
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also provided with dimples 52, which also extend downwardly to engage core
plate 16 below turbulizer 14. Openings 54 and 56 are also provided in
turbulizer
14 to register with openings 28,30 in end plate 12 to allow fluid to flow
transversely through turbulizer plate 14. Corner arcuate dimples 58 are also
provided in turbulizer plate 14 to help locate turbulizer plate 14 in the
assembly
of heat exchanger 10. If desired, arcuate dimples 58 could be provided at all
four
corners of turbulizer plate 14, but only two are shown in Figures 1 to 3.
These
arcuate dimples also strengthen the corners of heat exchanger 10.
Referring next to Figures 1 and 5 to 7, heat exchanger 10 includes
turbulizers 60 and 62 located between respective plates 16 and 18 and 18 and
20.
Turbulizers 60 and 62 are formed of expanded metal, namely, aluminum, either
by roll forming or a stamping operation. Staggered or offset transverse rows
of
convolutions 64 are provided in turbulizers 60, 62. The convolutions have flat
tops 66 to provide good bonds with core plates 14, 16 and 18, although they
could have round tops, or be in a sine wave configuration, if desired. Any
type
of turbulizer can be used in the present invention. As seen best in Figures 5
to 7,
part of one of the transverse rows of convolutions 64 is compressed or roll
formed or crimped together to form transverse crimped portions 68 and 69. For
the purposes of this disclosure, the term crimped is intended to include
crimping,
stamping or roll forming, or any other method of closing up the convolutions
in
the turbulizers. Crimped portions 68, 69 reduces short-circuit flow inside the
core plates, as will be discussed further below. It will be noted that only
turbulizers 62 have crimped portions 68,. Turbulizers 60 do not have such
crimped portions.
As seen best in Figure 1, turbulizers 60 are orientated so that the
transverse rows of convolutions 64 are arranged transversely to the
longitudinal
direction of core plates 16 and 18. This is referred to as a high pressure
drop
arrangement. In contrast, in the case of turbulizer 62, the transverse rows of
convolutions 64 are located in the same direction as the longitudinal
direction of
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core plates 18 and 20. This is referred to as the low pressure drop direction
for
turbulizer 62, because there is less flow resistance for fluid to flow through
the
convolutions in the same direction as row 64, as there is for the flow to try
to
flow through the row 64, as is the case with turbulizers 60.
Referring next to Figures 8 to 10, a modified turbulizer 63 is shown
where, in addition to crimped portions 68, 69, the distal ends or short edges
71,
73 are also crimped to help reduce short-circuit flow around the ends of the
turbulizers, as will be described further below.
Referring next to Figures 1 and 11 to 14, core plates 16, 18, 20 and 22
will now be described in detail. All of these core plates are identical, but
in the
assembly of heat exchanger 10, alternating core plates are turned upside down.
Figure 11 is a plan view of core plates 16 and 20, and Figure 12 is a plan
view of
core plates 18 and 22. Actually, Figure 12 shows the back or underside of the
plate of Figure 11. Where heat exchanger 10 is used to cool oil using coolant
such as water, for example, Figure 11 would be referred to as the water side
of
the core plate and Figure 12 would be referred to as the oil side of the core
plate.
Core plates 16 through 22 each have a planar central portion 70 and a first
pair of spaced-apart bosses 72, 74 extending from one side of the planar
central
portion 70, namely the water side as seen in Figure 11. A second pair of
spaced-
apart bosses 76, 78 extends from the opposite side of planar central portion
70,
namely the oil side as seen in Figure 12. The bosses 72 through 78 each have
an
inner peripheral edge portion 80, and an outer peripheral edge portion 82. The
inner and outer peripheral edge portions 80, 82 define openings or fluid ports
84,
85, 86 and 87. A continuous peripheral ridge 88 (see Figure 12) encircles the
inner peripheral edge portions 80 of at least the first pair of bosses 72, 74,
but
usually continuous ridge 88 encircles all four bosses 72,74, 76 and 78 as
shown
in Figure 12. Continuous ridge 88 extends from planar central portion 70 in
the
same direction and equidistantly with the outer peripheral edge portions 82 of
the second pair of bosses 76, 78.
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Each of the core plate 16 to 22 also includes a raised peripheral flange 90
which extends from planar central portion 70 in the same direction and
equidistantly with the outer peripheral edge portions 82 of the first pair of
bosses
72, 74.
As seen in Figure 1, core plates 16 and 18 are juxtaposed so that
continuous ridges 88 are engaged to define a first fluid chamber between the
respective plate planar central portions 70 bounded by the engaged continuous
ridges 88. In other words, plates 16, 18 are positioned back-to-back with the
oil
sides of the respective plates facing each other for the flow of a first
fluid, such
as oil, between the plates. In this configuration, the outer peripheral edge
portions 82 of the second pair of spaced-apart bosses 76,78 are engaged, with
the
respective fluid ports 85,84 and 84,85 in communication. Similarly, core
plates
18 and 20 are juxtaposed so that their respective peripheral flanges 90 are
engaged also to define a first fluid chamber between the planar central
portions
of the plates and their respective engaged peripheral flanges 90. In this
configuration, the outer peripheral edge portions 82 of the first pair of
spaced-
apart bosses 72,74 are engaged, with the respective fluid ports 87,86 and
86,87
being in communication. For the purposes of this disclosure, when two core
plates are put together to form a plate pair defining a first fluid chamber
therebetween, and a third plate is placed in juxtaposition with this plate
pair,
then the third plate defines a second fluid chamber between the third plate
and
the adjacent plate pair. In either case, the fluid ports 84 and 85 or 86 and
87
become inlets and outlets for the flow of fluid in a U-shaped flow path inside
the
first and second fluid chambers.
Referring in particular to Figure 11, a T-shaped rib 92 is formed in the
planar central portion 70. The height of rib 92 is equal to the height of
peripheral
flange 90. The head 94 of the T is located adjacent to the peripheral edge of
the
plate running behind bosses 76 and 78, and the stem 96 of the T extends
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longitudinally or inwardly between the second pair of spaced-apart bosses 76,
78. This T-shaped rib 92 engages the mating rib 92 on the adjacent plate and
forms a barrier to prevent short-circuit flow between the inner peripheral
edges
80 of the respective bosses 76 and 78. It will be appreciated that the
continuous
peripheral ridge 88 as seen in Figure 12 also produces a continuous peripheral
groove 98 as seen in Figure 11. The T-shaped rib 92 prevents fluid from
flowing
from fluid ports 84 and 85 directly into the continuous groove 98 causing a
short-circuit. It will be appreciated that the T-shaped rib 92 as seen in
Figure 11
also forms a complimentary T-shaped groove 100 as seen in Figure 12. The T-
shaped groove 100 is located between and around the outer peripheral edge
portions 82 of bosses 76, 78, and this promotes the flow of fluid between and
around the backside of these bosses, thus improving the heat exchange
performance of heat exchanger 10.
In Figure 12, the location of turbulizers 60 is indicated by chain dotted
lines 102. In Figure 11, the chain dotted lines 104 represent turbulizer 62.
Turbulizer 62 could be formed of two side-by-side turbulizer portions or
segments, rather than the single turbulizer as indicated in Figures 1 and 5 to
7. In
Figure 11, the turbulizer crimped portions 68 and 69 are indicated by the
chain-
dotted lines 105. These crimped portions 68 and 69 are located adjacent to the
stem 96 of T-shaped rib 92 and also the inner edge portions 80 of bosses 76
and
78, to reduce short-circuit flow between bosses 76 and 78 around rib 96.
Instead of using turbulizers 62 as indicated in Figures 1 and 11, the
turbulizers 63 of Figure 8 to 10 could be used in heat exchanger 10. In this
case,
the crimped end portions 71, 73 would be a barrier and would block fluid flow
from the turbulizer area to peripheral groove 98, again to reduce the bypass
flow
around peripheral groove 98. The crimped portions 68, 69 of turbulizer 62 and
the crimped portions 71, 73 of turbulizer 63 are located in the flow paths
inside
the fluid chambers inside the plate pairs to prevent or reduce short-circuit
flow
from the inlets and outlets defmed by fluid ports 84, 85 and 86, 87. It will
be
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appreciated that the locations in the turbulizers of the crimped portions 68,
69
and 71, 73 can be varied to suit any particular heat exchanger configuration
or to
control the flow path inside the plate pairs.
Core plates 16 to 22 also have another barrier located between the first
5 pair of spaced-apart bosses 72 and 74. This barrier is formed by a rib 106
as seen
in Figure 12 and a complimentary groove 108 as seen in Figure 11. Rib 106
prevents short-circuit flow between fluid ports 86 and 87 and again, the
complimentary groove 108 on the water side of the core plates promotes flow
between, around and behind the raised bosses 72 and 74 as seen in Figure 11.
It
10 will be appreciated that the height of rib 106 is equal to the height of
continuous
ridge 88 and also the outer peripheral edge portions 82 of bosses 76 and 78.
Similarly the height of the T-shaped rib or barrier 92 is equal to the height
of
peripheral flange 90 and the outer peripheral edge portions 82 of bosses 72
and
74. Accordingly, when the respective plates are placed in juxtaposition, U-
shaped flow passages or chambers are formed between the plates. On the water
side of the core plates (Figure 11), this U-shaped flow passage is bounded by
T-
shaped rib 92, crimped portions 68 and 69 of turbulizer 62, and peripheral
flange
90. On the oil side of the core plates (Figure 12), this U-shaped flow passage
is
bounded by rib 106 and continuous peripheral ridge 88.
Referring once again to Figure 1, heat exchanger 10 is assembled by
placing turbulizer plate 24 on top of end plate 26. The flat side of
turbulizer plate
24 goes against end plate 26, and thus undulating passageways 44 extend above
central planar portion 40 allowing fluid to flow on both sides of plate 24
through
undulating passageways 44 only. Core plate 22 is placed overtop turbulizer
plate
24. As seen in Figure 1, the water side (Figure 11) of core plate 22 faces
downwardly, so that bosses 72, 74 project downwardly as well, into engagement
with the peripheral edges of openings 54 and 56. As a result, fluid flowing
through openings 36 and 38 of end plate 26 pass through turbulizer openings
54,
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56 and bosses 72, 74 to the upper or oil side of core plate 22. Fluid flowing
through fluid ports 84 and 85 of core plate 22 would flow downwardly and
through the undulating passageways 44 of turbulizer plate 24. This flow would
be in a U-shaped direction, because rib 48 in turbulizer plate 24 covers or
blocks
longitudinal groove 108 in core plate 22, and also because the outer
peripheral
edge portions of bosses 72, 74 are sealed against the peripheral edges of
turbulizer openings 54 and 56, so the flow has to go around or past bosses
72,74.
Further core plates are stacked on top of core plate 22, first back-to-back as
is
the case with core plate 20 and then face-to-face as is the case with core
plate 18
and so on. Only four core plates are shown in Figure 1, but of course, any
number of core plates could be used in heat exchanger 10, as desired.
At the top of heat exchanger 10, the flat side of turbulizer plate 14 bears
against the underside of end plate 12. The water side of core plate 16 bears
against turbulizer plate 14. The peripheral edge portion 42 of turbulizer
plate 14
is coterminous with peripheral flange 90 of core plate 14 and the peripheral
edges of end plate 12, so fluid flowing through openings 28,30 has to pass
transversely through openings 54,56 of turbulizer plate 14 to the water side
of
core plate 16. Rib 48 of turbulizer plate 14 covers or blocks groove 108 in
core
plate 14. From this, it will be apparent that fluid, such as water, entering
opening 28 of end plate 12 would travel between turbulizer plate 14 and core
plate 16 in a U-shaped fashion through the undulating passageways 44 of
turbulizer plate 14, to pass up through opening 30 in end plate 12. Fluid
flowing
into opening 28 also passes downwardly through fluid ports 84 and 85 of
respective core plates 16,18 to the U-shaped fluid chamber between core plates
18 and 20. The fluid then flows upwardly through fluid ports 84 and 85 of
respective core plates 18 and 16, because the respective bosses defining ports
84
and 85 are engaged back-to-back. This upward flow then joins the fluid flowing
through opening 56 to emerge from opening 30 in end plate 12. From this it
will
be seen that one fluid, such as coolant or water, passing through the openings
28
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12
or 30 in end plate 12 travels through every other water side U-shaped flow
passage or chamber between the stacked plates. The other fluid, such as oil,
passing through openings 36 and 38 of end plate 26 flows through every other
oil side U-shaped passage in the stacked plates that does not have the first
fluid
passing through it.
Figure 1 also illustrates that in addition to having the turbulizers 60 and
62 orientated differently, the turbulizers can be eliminated altogether, as
indicated between core plates 20 and 22. Turbulizer plates 14 and 24 are
actually
shim plates. Turbulizer plates 14, 24 could be replaced with turbulizers 60 or
62,
but the height or thickness of such turbulizers would have to be half that of
turbulizers 60 and 62 because the spacing between the central planar portions
70
and the adjacent end plates 12 or 26 is half as high the spacing between
central
planar portions 70 of the juxtaposed core plates 16 to 22.
Referring again to Figures 11 and 12, planar central portions 70 are also
formed with further barriers 110 having ribs 112 on the water side of planar
central portions 70 and complimentary grooves 114 on the other or oil side of
central planar portions 70. The ribs 112 help to reduce bypass flow by helping
to
prevent fluid from passing into the continuous peripheral grooves 98, and the
grooves 114 promote flow on the oil side of the plates by encouraging the
fluid
to flow into the corners of the plates. Ribs 112 also perform a strengthening
function by being joined to mating ribs on the adjacent or juxtaposed plate.
Dimples 116 are also provided in planar central portions 70 to engage mating
dimples on juxtaposed plates for strengthening purposes.
Referring next to Figures 15 and 16, some further plates are shown for
producing yet another preferred embodiment of a self-enclosing heat exchanger
according to the present invention. In this embodiment, the plates 150, 152,
154
and 156 are circular and they are identical in plan view. Figure 15 shows the
oil
side of a pair of plates 150, 152 that have been unfolded along a chain-dotted
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fold line 158. Figure 16 shows the water side of a pair of plates 154, 156
that
have been unfolded along a chain-dotted fold line 160. Again, core plates 150
to
156 are quite similar to the core plates shown in Figures 1 to 14, so the same
reference numerals are used in Figures 15 and 16 to indicate components or
portions of the plates that are functionally the same as the embodiment of
Figures 1 to 14.
In the embodiment of Figures 15 and 16, the bosses of the first pair of
spaced-apart bosses 72, 74 are diametrically opposed and located adjacent to
the
continuous peripheral ridge 88. The bosses of the second pair of spaced-apart
bosses 76, 78 are respectively located adjacent to the bosses 74, 72 of the
first
pair of spaced-apart bosses. Bosses 72 and 78 form a pair of associated input
and
output bosses, and the bosses 74 and 76 form a pair of associated input and
output bosses. Oil side barriers in the form of ribs 158 and 160 reduce the
likelihood of short circuit oil flow between fluid ports 86 and 87. As seen
best in
Figure 15, ribs 158, 160 run tangentially from respective bosses 76, 78 into
continuous ridge 88, and the heights of bosses 76, 78, ribs 158, 160 and
continuous ridge 88 are all the same. The ribs or barriers 158, 160 are
located
between the respective pairs of associated input and output bosses 74, 76 and
72,
78. Actually, barriers or ribs 158, 160 can be considered to be spaced-apart
barrier segments located adjacent to the respective associated input and
output
bosses. Also, the barrier ribs 158, 160 extend from the plate central planar
portions in the same direction and equidistantly with the continuous ridge 88
and
the outer peripheral edge portions 82 of the second pair of spaced-apart
bosses
76, 78.
A plurality of spaced-apart dimples 162 and 164 are formed in the plate
planar central portions 70 and extend equidistantly with continuous ridge 88
on
the oil side of the plates and raised peripheral flange 90 on the water side
of the
plates. The dimples 162, 164 are located to be in registration in juxtaposed
first
and second plates, and are thus joined together to strengthen the plate pairs,
but
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14
dimples 162 also function to create flow augmentation between the plates on
the
oil side (Figure 15) of the plate pairs. It will be noted that most of the
dimples
162, 164 are located between the barrier segments or ribs 158, 160 and the
continuous ridge 88. This permits a turbulizer, such as turbulizer 60 of the
Figure 1 embodiment, to inserted between the plates as indicated by the chain-
dotted line 166 in Figure 15. Also, a turbulizer with crimped portions, like
the
crimped end portions 71, 73 of turbulizers 63 could be used to help reduce
bypass flow around the periphery of the plates.
On the water side of plates 154, 156 as seen in Figure 16, a barrier rib
168 is located in the centre of the plates and is of the same height as the
first pair
of spaced-apart bosses 72, 74. Barrier rib 168 reduces short circuit flow
between
fluid ports 84 and 85. The ribs 168 are also joined together in the mating
plates
to perform a strengthening function. Alternatively, a turbulizer like
turbulizer 62
of Figure 1 could be used where the central crimped portions 68, 69 would take
the place of barrier rib 168, the latter would then not be formed in plates
150,
152.
Barrier ribs 158, 160 have complimentary grooves 170, 172 on the
opposite or water sides of the plates, and these grooves 170, 172 promote flow
to
and from the peripheral edges of the plates to improve the flow distribution
on
the water side of the plates. Similarly, central rib 168 has a complimentary
groove 174 on the oil side of the plates to encourage fluid to flow toward the
periphery of the plates.
Referring next to Figures 17 to 20, yet another embodiment of a self-
enclosing heat exchanger will now be described. In this embodiment, a
plurality
of elongate flow directing ribs are formed in the plate planar central
portions to
prevent short-circuit flow between the respective ports in the pairs of spaced-
apart bosses. In Figures 17 to 20, the same reference numerals are used to
indicate parts and components that are functionally equivalent to the
embodiments described above.
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Figure 17 shows a core plate 212 that is similar to core plates 16, 20 of
Figure 1, and Figure 18 shows a core plate 214 that is similar to core plates
18,
22 of Figure 1. In core plate 212, the barrier rib between the second pair of
spaced-apart bosses 76, 78 is more like a U-shaped rib 216 that encircles
bosses
5 76, 78, but it does have a central portion or branch 218 that extends
between the
second pair of spaced-apart bosses 76, 78. The U-shaped portion of rib 216 has
distal branches 220 and 222 that have respective spaced-apart rib segments
224,
226 and 228, 230 and 232. The distal branches 220 and 222, including their
respective rib segments 224, 226 and 228, 230 and 232 extend along and
10 adjacent to the continuous peripheral groove 98. Central branch or portion
218
includes a bifurcated extension formed of spaced-apart segments 234, 236, 238
and 240. It will be noted that all of the rib segments 224 through 240 are
asymmetrically positioned or staggered in the plates, so that in juxtaposed
plates
having the respective raised peripheral flanges 90 engaged, the rib segments
15 form half-height overlapping ribs to reduce bypass or short-circuit flow
into the
continuous peripheral groove 98 or the central longitudinal groove 108. It
will
also be noted that there is a space 241 between rib segment 234 and branch
218.
This space 241 allows some flow therethrough to prevent stagnation which
otherwise may occur at this location. As in the case of the previously
embodiments, the U-shaped rib 216 forms a complimentary groove 242 on the
oil side of the plates as seen in Figure 18. This groove 242 promotes the flow
of
fluid between, around and behind bosses 76, 78 to improve the efficiency of
the
heat exchanger formed by plates 212, 214.
The oil side of the plates can also be provided with turbulizers as
indicated by chain-dotted lines 244, 246 in Figure 18. These turbulizers
preferably will be the same as turbulizers 60 in the embodiment of Figure 1.
However, turbulizers like turbulizer 63 could also be used, in which case the
crimped portions would run in the longitudinal direction of plates 212, 214.
The
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16
crimped end portions 71, 73 of such turbulizers 63 could be crimped
intermittently to produce the same result as rib segments 224 to 232, as could
the
central crimped portions 68, 69 to give the same effect as rib segments 234 to
240. Of course, where crimped turbulizers are used, the various rib segments
would not be used.
It is also possible to make the bifurcated extension of central branch 218
so that the forks consisting of respective rib segments 234, 236 and 238, 240
diverge. This would be a way to adjust the flow distribution or flow
velocities
across the plates and achieve uniform velocity distribution inside the plates.
In the above description, for the purposes of clarification, the terms oil
side and water side have been used to describe the respective sides of the
various
core plates. It will be understood that the heat exchangers of the present
invention are not limited to the use of fluids such as oil or water. Any
fluids can
be used in the heat exchangers of the present invention. Also, the
configuration
or direction of flow inside the plate pairs can be chosen in any way desired
simply by choosing which of the fluid flow ports 84 to 87 will be inlet or
input
ports and which will be outlet or output ports.
Having described preferred embodiments of the invention, it will be
appreciated that various modifications may be made to the structures described
above. For example, the heat exchangers can be made in any shape desired.
Although the heat exchangers have been described from the point of view of
handling two heat transfer fluids, it will be appreciated that more than two
fluids
can be accommodated simply by nesting or expanding around the described
structures using principles similar to those described above. Further, some of
the
features of the individual embodiments described above can be mixed and
matched and used in the other embodiments as will be appreciated by those
skilled in the art.
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As will be apparent to those skilled in the art in the 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 by the following claims.
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