Note: Descriptions are shown in the official language in which they were submitted.
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RADIAL FLOW ANNULAR HEAT EXCHANGERS
This invention relates to heat exchangers, and in particular, to oil coolers
of the so called "doughnut" type that can be used separately or in conjunction
with oil filters in automotive and other engine and transmission cooling
applications.
Oil coolers have been made in the past out of a plurality of stacked plate
pairs located in a housing or canister. The canister usually has inlet and
outlet
fittings for the flow of engine coolant into and out of the canister
circulating
around the plate pairs. The plate pairs themselves have inlet and outlet
openings
and these openings are usually aligned to form manifolds, so that the oil
passes
through all of the plate pairs simultaneously. These manifolds communicate
with
oil supply and return lines located externally of the canister. An example of
such
an oil cooler is shown in Japanese Utility Model Laid Open Publication No. 63-
23579 published February 16, 1988.
Where the oil cooler is used in conjunction with an oil filter, the plate
pairs are usually in the form of an annulus and a conduit passes through the
2o centre of the annulus delivering oil to or from the filter located above or
below
the oil cooler and connected to the conduit. The oil can pass through the
filter
and then the oil cooler, or vice-versa. Examples of such oil coolers are shown
in
United States patents Nos. 4,967,835 issued to Thomas E. Lefeber and No.
5,406,910 issued to Charles M. Wallin.
A di~culty with these prior art oil coolers, however, is that they are not
particularly efficient. They also often suffer from the disadvantage of high
pressure drop on the oil side of the cooler.
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The heat exchanger of the present invention is very efficient with
relatively low pressure drop. A first exchange fluid travels circumferentially
through ringlike plate pairs, and all of a second heat exchange fluid flows
between the plate pairs transversely relative to the first heat exchange
fluid.
According to one aspect of the invention, there is provided a heat
exchanger which comprises a plurality of stacked plate pairs consisting of
face-
to-face, mating ringlike plates. Each plate has an outer peripheral flange, an
annular inner boss having a portion thereof located in a common plane with the
peripheral flange, and an intermediate area located between the peripheral
flange
and the inner boss. The peripheral flanges and inner bosses in the mating
plates
are joined together. The intermediate areas have spaced-apart portions to form
an
inner flow passage between the plates. The plate intermediate areas have
spaced-apart intermediate bosses located between the outer peripheral flange
and
the inner boss that extend from the intermediate area in a direction opposite
to
the peripheral flange and inner boss. The intermediate bosses define inlet and
outlet openings and are arranged such that in back-to-back plate pairs, the
intermediate bosses are joined and the respective inlet and outlet openings
communicate to define inlet and outlet manifolds for the flow of a first
exchange
fluid circumferentially through the inner flow passages from the inlet
manifold to
the outlet manifold. The adjacent intermediate areas in back-to-back plate
pairs
define outer flow passages therebetween. Also, a header encloses one of the
inner bosses and outer peripheral flanges. The header includes a flow port for
the
flow of a second heat exchange fluid therethrough to force the second heat
exchange fluid to flow transversely through the outer flow passages.
According to another aspect of the invention, there is provided a method
of transferring heat energy between lubricating fluids and engine coolant. The
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method comprises the steps of providing a plurality of ringlike, closely
spaced-
apart, stacked plate pairs having inner flow passages therebetween and outer
flow passages between the plate pairs. All of one of the fluid and the coolant
is
passed circumferentially through the plate pairs, and all of the other of the
fluid
and the coolant is passed transversely between the plate pairs.
Preferred embodiments of the invention will now be described, by way of
example, with reference to the accompanying drawings, in which:
Figure 1 is a diagrammatic vertical sectional view taken through a first
preferred embodiment of a combination heat exchanger and oil filter employing
a preferred embodiment of a heat exchanger according to the present invention;
Figure 2 is an enlarged perspective view, partly broken away, of the heat
exchanger employed in the embodiment shown in Figure 1;
Figure 3 is an enlarged perspective view similar to Figure 2, but showing
the underside of the heat exchanger of Figure 2;
Figure 4 is an enlarged perspective view showing the inside surface of
one of the plates used to form the plate pairs of the heat exchanger
embodiment
shown in Figures 2 and 3;
Figure 5 is a plan view of the plate shown in Figure 4;
Figure 6 is a further enlarged sectional view taken along lines 6-6 of
Figure 5 and showing additional plates stacked above and below the plate of
Figures 4 and 5;
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Figure 7 is a vertical sectional view similar to Figure 6 but showing
another embodiment where the plate header is formed on the outer periphery of
the plate pairs;
Figure 8 is an enlarged sectional view of the lower left comer of Figure 1
showing yet another embodiment of a heat exchanger according to the present
invention;
Figure 9 is a perspective view similar to Figure 4, but showing another
preferred embodiment of a plate used to make a heat exchanger according to the
present invention;
Figure 10 is a plan view of the plate shown in Figure 9;
Figure 11 is a diagrammatic vertical sectional view similar to Figure 1,
but showing another preferred embodiment of a combination heat exchanger and
oil filter employing another embodiment of a heat exchanger according to the
present invention therein;
Figure 12 is an enlarged perspective view, partly broken away, of the heat
exchanger employed in the embodiment shown in Figure 11;
Figure 13 is a perspective view simlar to Figure 4 but showing the plate
used to make the heat exchanger embodiment shown in Figure 12;
Figure 14 is a vertical sectional view taken along lines 14-14 of Figure 13
and showing additional plates stacked above and below the plate of Figure 13;
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Figure 15 is a plan view of another preferred embodiment of a ringlike
heat exchanger plate used to make a heat exchanger according to the present
invention;
Figure 16 is a plan view of a top or bottom plate used to make a heat
exchanger using the plates shown in Figure 15;
Figure 17 is a perspective view similar to Figures 4 and 9, but showing
another embodiment of a plate in combination with a turbulizer as used to make
1 o a heat exchanger according to the present invention;
Figure 18 is a diagrammatic vertical sectional view similar to Figures 1
and 11, but showing another preferred embodiment of a heat exchanger as used
with a conventional oil filter to make a combination heat exchanger and
filter;
Figure 19 is an enlarged perspective view, partly broken away, of the heat
exchanger shown in Figure 18;
Figure 20 is a plan view of another embodiment of a plate used to make a
heat exchanger according to the present invention;
Figure 21 is a plan view of an optional spacer that may be used with the
plates of Figure 20;
Figure 22 is a perspective view looking at the inside of another
embodiment of a plate used to make a heat exchanger according to the present
invention;
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Figure 23 is a plan view of the plate shown in Figure 14;
Figure 24 is a plan view of yet another embodiment of a plate used to
make a heat exchanger according to the present invention; and
Figure 25 is a plan view of yet another embodiment of a plate used to
make a heat exchanger according to the present invention.
Referring firstly to Figure 1, a preferred embodiment of a combination
heat exchanger and oil filter according to the present invention is generally
indicated by reference numeral 10. It will be appreciated, however, that any
fluid
could be used in this invention, not just oil, so the term "oil" shall-mean
any heat
exchange fluid for the purposes of this disclosure. Combination unit 10
includes
a housing 12 containing an oil filter 14 and a preferred embodiment of a heat
exchanger according to the present invention indicated by reference numeral
16.
Oil filter 14 is conventional and is not per se considered to be part of the
present
invention. Oil filter 14 is of the annular type and in Figure 1, oil flows
from
inside the housing inwardly through the filter walls to a central axial
chamber 15
and passes downwardly through a pipe or conduit 18 to exit from combination
2o unit 10. However, the oil flow direction could be reversed, so that oil
enters
through conduit 18 and passes radially outwardly through the filter into
housing
12. In the embodiment shown in Figure 1, oil preferably flows from the housing
inwardly through the filter and exits through conduit 18. Heat exchanger 18
will
be described in more detail below, but before leaving Figure 1, it will be
noted
that housing 12 has a bottom plate 19 containing openings 20 therein for the
passage of oil therethrough into heat exchanger 16 depending upon which way it
is desired to have the oil flow through filter 14. Conduits 22 and 24 are also
attached to bottom plate 19 for the entry and exit of coolant into and out of
heat
exchanger 16.
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Referring next to Figures 2 to 6, heat exchanger 16 is formed of a
plurality of stacked plate pairs 30 consisting of face-to-face mating, annular
or
ringlike plates 32. As seen best in Figures 4 to 6, each plate 32 has an outer
peripheral flange 34, an annular inner boss 36 having a portion 37 located in
a
common plane with outer peripheral flange 34, and an intermediate area 39
located between peripheral flange 34 and inner boss 36. A plurality of
alternating
ribs and grooves 38, 40 are formed in intermediate area 39 and extend between
the inner boss 36 and the peripheral flange 34. The ribs and grooves 38, 40
are
flow augmentation means and are angularly disposed and in the form of spiral
or
involute curves, so that the ribs and grooves in the respective plates that
make up
plate pairs 30 cross forming an undulating inner flow passage 42 between the
plates of each plate pair 30. Similarly, the ribs and grooves 38, 40 in
adjacent
back-to-back plate pairs cross forming undulating outer flow passages 44
between the plate pairs 30. Outer flanges 34 contain optional alignment
notches
45 to assist in the proper alignment of plates 32 during the assembly of heat
exchanger 16. Such alignment notches could be used in all of the embodiments
of the present invention, if desired.
Plates 32 have spaced-apart intermediate bosses 46 located between the
outer peripheral flange 34 and the inner boss 36 and extending in a direction
from the intermediate area 39 in a direction opposite to peripheral flange 34
and
inner boss 36. . Intermediate bosses 46 define inlet and outlet openings 48,
50.
The intermediate bosses 46 are arranged such that in back-to-back plate pairs,
the respective inlet and outlet openings 48, 50 are joined around their
peripheries
to communicate and define inlet and outlet manifolds 52, 54 (see Figure 3) for
the flow of a first heat exchange fluid, such as engine coolant,
circumferentially
inside or through the inner flow passages of the plate pairs from inlet
manifold
52 to outlet manifold 54. The adjacent intermediate areas 39 in back-to-back
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plate pairs 30 define outer flow passages 44 therebetween. Heat exchanger 16
has top and bottom closure plates 56, 58. Bottom closure plate 58 has openings
62, 64 which register with respective inlet and outlet manifolds 52, 54.
Conduits
22, 24 (see Figure 1) pass through housing bottom plate 19 to communicate with
openings 62, 64.
Ribs 38 and grooves 40 have a predetermined height and intermediate
bosses 46 have a height, or depth as seen in Figure 4, that is at least as
high as
ribs 38, and preferably the same height as ribs 38, so that when the plate
pairs
are placed back-to-back as seen best in Figure 6, the ribs 38 on adjacent
plates
touch as do the outer surfaces of intermediate bosses 46. However, as seen
best
in Figure 6, the height of inner annular bosses 36 and outer peripheral
flanges 34
is greater than the height of the ribs and grooves, so that the adjacent ribs
38 on
the inside of plate pairs 30 are slightly spaced apart. This reduces the water-
side
pressure drop for the coolant flowing through plate pairs 30.
Since intermediate bosses 46 are located adjacent to one another, a radial
rib 66 (see Figures 4 and 5) extends between the intermediate bosses 46 from
the
inner boss 36 to the outer peripheral flange 34. Radial rib 66 is in the same
plane
as or has the same height as inner boss 36 and outer peripheral flange 34, so
that
when two plates are put together to form a plate pair 30, the respective
radial ribs
66 engage one another to prevent by-pass flow from inlet opening 48 to outlet
opening 50. Radial ribs 66 also form radial grooves on the outside or oil side
of
the plate pairs. These radial grooves improve the radial or transverse flow
between the plate pairs near and around intermediate bosses 46.
Inner peripheral flanges 68 are formed on annular inner bosses 36 and
have mating flange portions 69 located in a common plane with the intermediate
bosses 46, so that the inner peripheral flanges 68 on back-to-back plate pairs
are
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joined together to form, with the inner bosses 36, a header 70 (see Figure 6)
to
cause all of the coolant entering inlet opeW ngs ~i flow transversely or
radially
through the outer flow passages 44 between the back-to-back plate pairs 30.
Inner boss 3b includes a plurality of apertures 72 spaced around inner
boss 36. When plate pairs 30 are stacked together, apertures ?2 are aligned or
in
registration to form flow ports for supplying fluid to header 70.
Referring nexl; to Figure 7, which is a view similar to Figure 6, but which
shows another embodiment of a heat exchanger ~ 9 according to the present
invention having stacked plate pairs that are similar to the embodiment of
Figures 1 to 6, but where the inner header 70 of Figure 6 has been eliminated.
Primed reference numerals are used in Figures 7 to 25 to indicate modified
components of the embodiment shown in Figures 1 to 6. Inner bosses 36' have
been truncated leaving annular slots 80 for the flow of fluid into or out of
the
outer flow passages 44. between the plate pairs. In this embodiment, outer
distal
flanges 74 form a header enclosing outer peripheral flanges 34' to cause all
of the
respective heat exchange fluid to pass transversely or radially between the
plate
pairs. In this embodiment also, the inner annular boss 36' and outer
peripheral
flange 34' have a height that is equal to the height of the ribs and grooves,
so that
the adjacent ribs 38 in inner flow passages 42' are not spaced-apart as in the
embodiment shown in Figures 1 and 6. However, the adjacent ribs 38 in the
inner flow passages 42' could be spaced-apart as in Figure 6, or the Figure 6
embodiment could be made like Figure 7 with ribs 38 not spaced-apart, if
desired.
Figure 8 shows another embodiment of a heat exchanger s o ~ where a
header 82 is formed by the annular space defined by top and bottom closure
plates 56, 58 and conduit 18 sealingly engaged therein. Neither the inner
bosses
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36' nor the outer peripheral flanges 34 have additional flanges formed thereon
to
form headers. Bottom closure plate 58 includes a flow port 84 for the flow of
fluid into or out of header 82.
Referring next to Figures 9 and 10, another embodiment of a ringlike
plate 85 is shown which is similar to plate 32 of Figures 4 and 5, but which
has a
plurality of spaced-apart dimples 87 and 89 formed in the intermediate area 39
as
the flow augmentation means instead of ribs 38 and grooves 40. Dimples 87
extend into the outer flow passages 44 and dimples 89 extend into the inner
flow
passages 42. Dimples 87, 89 have a predetermined height which, in the case of
dimples 87, is preferably equal to the height of intenmediate bosses 46.
However,
some or all of the dimples 87 could have a height that is less than
intermediate
bosses 46.
If desired, plates 85 could be formed with outer distal flanges like flanges
74 in the embodiment shown in Figure 7 to define headers 76 at the outer
periphery of the plates, either in addition to or instead of the inner
peripheral
flanges 68 and headers 70 as shown in Figure 6.
Dimples 87 and 89 are shown arranged in respective circumferential rows
and generally equi-spaced, but they could be mixed in orientation and spaced
apart differently to achieve specific flow effects inside and between the
plate
pans.
Figure 11 shows another preferred embodiment of a combination heat
exchanger and filter 91 which is similar to combination unit 10 of Figure l,
but
which employs a heat exchanger 28 as shown in detail in Figures 12 to 14. Top
plate 56' in heat exchanger 28 is the bottom wall of housing 12' that contains
filter 14, and a removable lid 93 allows for the replacement of filter 14.
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Referring in particular to Figures 12 to 14, heat exchanger 28 could be
considered to be a modification to heat exchanger 16 of Figures 2 to 6. In
heat
exchanger 28, the plates 32' have outer peripheral flanges 34' that have been
extended radially, and an outer distal flange 74 is formed on outer peripheral
flange 34' having mating flange portions 75. Mating flange portions 75 are
located in a common plane with the intermediate bosses 46, so that the distal
flanges 74 on back-to-back plate pairs 30' are joined to form, with the outer
peripheral flanges 34', a header 76. Apertures 77 are fonmed in outer
peripheral
flanges 34' and are aligned in the stacked plate pairs to form flow ports to
receive
fluid flowing between the back-to-back plate pairs. However, it will be
appreciated that the flow direction could be reversed, so that header 76
supplies
fluid to flow radially inwardly toward the centre of heat exchanger 28, if
desired.
As seen best in Figure 12, top closure plate 56' is formed with a plurality
of openings 78 that communicate with apertures 77 and form part of headers 76
and also communicate with the inside of housing 12'. It will also be
appreciated
that heat exchanger 28 has two headers 70 and 76 with aligned apertures
forming
flow ports for these headers.
Figure 15 shows a plate 95 that is a modification of plate 32' such that
plate 95 is rectangular in shape or plan view. Outer peripheral flange 34" is
rectangular as well, and although inner boss 36 is shown to be circular or
annular, inner boss 36 could be rectangular as well, if desired. For the
purposes
of the present specification, plate 95 is still considered to come within the
term
annular or ringlike, the flow from inlet opening 48 to outlet opening 50 is
still
considered to be circumferential, and the flow from inner apertures 72 to
outer
apertures 77 is still considered to be radial or transverse with respect to
the
circumferential flow inside the plate pairs.
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Figure 16 shows a modified top plate 56' for use with plates 95. Top plate
56' has peripheral openings 97 that vary in size to obtain uniform flow
distribution in the radial or transverse direction. It will be noted that the
corner
openings 97 are particularly large to increase the flow to the corners of a
heat
exchanger made with these plates. Alternatively, uniformly sized openings 97
spaced closer or further apart could be used to give a desired flow
distribution
instead of differently sized apertures 97. These aperture size or shape
differences
could also be employed in connection with apertures 77 in the core plates 95
of
Figure 15, if desired.
to
Figure 17 shows yet another embodiment of a plate 99 used to form a heat
exchanger according to the present invention which, like the plate 85 shown in
Figures 9 and 10, has another type of flow augmentation instead of ribs and
grooves as shown in Figures 1 to 6 or dimples as shown in Figures 9 and 10. In
the Figure 17 embodiment, an expanded metal turbulizer 101 is used as the flow
augmentation means. Of course, turbulizer 101 could be formed of other
materials than expanded metal, such as plastic mesh. Figure 17 is a view of
plate
99 looking at the oil side or outside of a plate pair. The intermediate areas
39 are
located under turbulizer 101 and are still spaced-apart to form inner flow
passages inside the plate pairs. Turbulizer 101 could be any type of
turbulizer,
and if it has a flow resistance that varies in a particular direction,
apertures 72
and 77 could be arranged differently or varied in size to suit the turbulizer
and
maintain uniform radial or transverse flow between the plate pairs.
Turbulizers
101 could be employed inside the plate pairs in the inner flow passages as
well
as, or instead of, the turbulizers 101 used in the outer flow passages as
shown in
Figure 17.
Figures 18 and 19 show a heat exchanger 28' that is a modification to the
heat exchanger 28 shown in Figures 11 and 12. In heat exchanger 28' an annular
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filter seat 103 is mounted on top of top closure plate 56 to accommodate a
conventional spin-on oil filter 107 that screws onto conduit 18. Filter seat
103
has inner openings 105 to allow fluid emerging from headers 76 or openings 78
to be delivered to filter inlet openings 109.
Figure 20 shows the inside or water side surface of a plate 32' where the
inner annular boss 3f and the outer peripheral flange 34' are the same height
with respect to both the intermediate bosses 46 and inner peripheral flange 68
as
the height of the ribs and grooves 38, 40. If it is desired to reduce the
pressure
drop inside the plate pairs in this embodiment, a spacer 86 as shown in Figure
21
can be used between the plates of the plate pairs. Spacer 86 has an outer
annular
portion 88 which is located between outer peripheral flanges 34' and an inner
annular portion 90 which is located between inner annular bosses 3f. Inner
annular portion 90 has a plurality of apertures 92 therein to correspond with
apertures 72 in inner boss 3f. Rotation of spacer 86 relative to plates 32'
causes
apertures 92 to act as valves to obtain a predetermined setting or adjustment
of
the flow through apertures 72 during manufacture of heat exchangers using this
type of plate.
Figures 22 and 23 show a plate 94 that is similar to plate 32' of Figure 20,
but which has a peripheral by-pass groove 96 located inside the plate pairs
adjacent to the outer peripheral flange 34'. By-pass groove 96 has a first end
portion 98 located adjacent to and communicating with one of the intermediate
bosses 46 and extends just over half way around the perimeter of plate 94 to a
second end portion 100, so that when two plates 94 are arranged face-to-face,
end portions 100 overlap and by-pass groove 96 forms a half height groove
extending all the way around the periphery of the plate pair from one
intermediate boss 46 to the other. By-pass groove 96 is used to reduce
internal
pressure drop inside the plate pairs, if desired.
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Figure 24 shows a plate 102 similar to plate 94 of Figure 23, but having at
least one by-pass groove 104 extending between intermediate bosses 46.
Actually, because the grooves between intermediate bosses 46 overlap and cross
each other, several half height by-pass channels extend between intermediate
bosses 46. Again, these by-pass channels are provided to reduce pressure drop
inside the plate pairs. If desired, the by-pass grooves 104 can be used
instead of
peripheral by-pass groove 96.
Figure 25 shows a plate 102' that is a modification of plate 102 of Figure
l0 24. In plate 102' the by-pass grooves 104 are formed with flow limiting
indentations 106 to control or set a predetermined amount of by-pass flow
between intermediate bosses 46.
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 intermediate bosses containing the inlet and outlet
openings could be made smaller, so that inner annular bosses 36 could be the
same width all around their circumference allowing apertures 72 to extend
around the full circumference of these bosses. The various heat exchangers can
be made using any number of plate pairs and the various plate pair embodiments
could be mixed and matched to achieve a particular desired performance. The
top and bottom closure plates could be eliminated in certain applications
where
other means are used to close the various flow manifolds formed by openings in
the plates. For example, end plates could be used that are similar to plates
used
to make the plate pairs, in which case, the various inlet and outlet openings
and
apertures in these end plates would not be punched out. Other configurations
for
the ribs and grooves and dimples and turbulizers could also be employed in the
plates, if desired.
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It will also be appreciated that although the preferred embodiments have
been described for use as oil coolers, the heat exchangers of the present
invention can be used for cooling or heating other engine fluids, such as,
fuel,
transmission fluid, hydraulic steering fluid, refrigerant and even engine
coolant
itself. Either fluid can pass between the plate pairs or through the plate
pairs, and
the heat exchangers of the present invention can be used to heat fluids as
well as
cool them. Further, the heat exchangers of the present invention can be used
in
applications other than in the automotive industry.
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.
20
