Note: Descriptions are shown in the official language in which they were submitted.
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HEAT EXCHANGER WITH END PLATE PROVIDING
MOUNTING FLANGE
The present invention relates to plate-type heat exchangers, and,
more particular, to heat exchangers comprising a stack of dished plates.
Plate-type heat exchangers comprising a stack of heat exchanger
plates are well known for a variety of purposes, including heat exchange
between oil and a heat exchange fluid. One category of this type of heat
exchanger uses plates which have a generally planar plate bottom and a
sloped peripheral sidewall extending around the bottom and these plates
can be referred to as dished or tub shaped plates. The plates nest with
adjacent plates in the stack. During assembly, the sidewalls are sealingly
connected together, for example, by brazing, to form sealed flow passages
for heat exchange fluids.
A known way of mounting a stacked plate heat exchanger is to
mount a planar base plate at one end of the stack, for example, the
bottom end. The base plate can be brazed to the heat exchanger i.e. with
or without the use of a shim plate. In such designs where the base plate
is brazed to the heat exchanger core, the first channel peripheral sidewall
is the weakest location on the heat exchanger, as this sidewall is not
covered by another core plate sidewall outside of it. A known solution to
reinforce the first channel sidewall is to connect this bottom core plate to
the base plate by means of a belt connector extending about the periphery
of the core plate. The connecting belt can strengthen the weakest location
of the heat exchanger but it increases the amount of material required and
belts of this type can be difficult to manufacture and relatively costly.
Generally, the stamping angle to form these belts is higher than 90
degrees, requiring the belts to be stamped in two directions. Because such
belts are made from plates, the use of such belts results in high material
usage, with the center of each plate being removed and not used.
Another known solution to strengthen the first channel is to use a second
core plate between the base plate and the first core plate.
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There is a need for an improved heat exchanger of the
aforementioned type with an improved attachment arrangement.
According to one embodiment of the invention, a heat exchanger
comprises a heat exchanging core including a plurality of dish-type plates
arranged in a stack with fluid flow passages being provided between
adjacent plates in the stack. Each plate comprises a central main plate
section having a peripheral edge, an edge wall extending outwardly from
and around the peripheral edge at an acute angle to a plane defined by
the main plate section, and inlet and outlet holes provided through the
main plate section for passage of heat exchange fluids. The plates are in
nested, sealed arrangement with one another and the main plate sections
of adjacent plates are spaced from one another to form the fluid flow
passages. A base plate for supporting the heat exchanging core is rigidly
attached to one of the dish-type plates at one end of the stack. This base
plate is formed with an integral ridge extending snugly along and adjacent
to the edge wall of the one dish-type plate. At least one section of the
ridge is spaced from an adjacent edge of the base plate so as to provide at
least one mounting flange for the heat exchanger.
In an exemplary version of this heat exchanger, the integral ridge
has a U-shaped transverse cross-section and has inner and outer ridge
walls. The inner ridge wall extends parallel to an adjacent outer surface of
the edge wall and is attached directly thereto.
According to another embodiment of the invention, a heat
exchanger for heat exchange between two heat exchange liquids
comprises a heat exchanging core formed of a plurality of formed plates
arranged and connected to one another in a stack. The plates include first
end plate (also called top core plate) and second end plate (also called the
bottom core plate) and at least one intermediate plate arranged between
the end plates. Each of the formed plates has a central main plate section
= and the first end plate and the at least one intermediate plate each have
an edge wall extending outwardly from and around its respective main
plate section at an acute angle to a plane defined by the main plate
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section. The core also has inlet and outlet holes in the main plate sections
for passage of the heat exchange liquids into and out of the core. The
formed plates are in nested, sealed engagement with one another. The
main plate sections of at least the first end plate and the at least one
intermediate plate are spaced apart from respective adjacent main plate
sections to form liquid flow passages. The second end plate is formed with
an integral ridge extending snugly along and adjacent to the edge wall of
the adjacent intermediate plate. At least one section of the ridge is
spaced from an adjacent edge of the second end plate so as to provide at
least one mounting flange for the heat exchanger.
In an exemplary version of this heat exchanger, the second end
plate is made of substantially thicker metal plate than the rest of the
formed plates.
According to still another embodiment of the invention, an oil heat
exchanger for heat exchange between oil and a heat exchange liquid
comprises a heat exchange unit formed of a plurality of dished plates
= connected together in a sealing manner and arranged in a stack. The stack
includes first and second end plates and a plurality of intermediate plates.
Each of the dished plates has a substantially planar, main plate section
which is spaced apart from the or each adjacent main plate section of
another dished plate to form a respective liquid flow passage. The main
plate sections have inlet and outlet holes for separate passage of the oil
and the heat exchange liquid into and out of the liquid flow passages. The
second end plate is formed with an integral ridge extending snugly along
and around an edge wall of the dished plate adjacent thereto. Two or more
sections of the ridge are each spaced from an adjacent edge of the second
end plate so as to provide mounting flanges for the heat exchanger.
The invention will now be described by way of example only, with
reference to the accompanying drawings in which:
= Figure 1 is a perspective view showing a heat exchanger base plate
and core plate according to the prior art, without reinforcement;
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Figure 2 is an exploded view of a stacked heat exchanger according
to the prior art, without reinforcement;
Figure 3 is a cross-sectional side elevation schematically illustrating
a stack of dished heat exchanger plates rigidly attached to a base plate
with a belt reinforcement according to the prior art;
Figure 4 is a perspective view similar to Figure 1 but showing a base
plate and an attached core plate constructed according to one embodiment
of the invention;
Figure 5 is a cross-sectional view taken along the line V-V of Figure
4;
Figure 6 is a perspective view of the base plate and adjacent core
plate shown in Figure 4 with both plates shown cutaway so as to show
their transverse cross-sections;
Figure 7 is a perspective view similar to Figure 4 but showing an
alternate form of base plate only;
Figure 8 is a plan view of the base plate of Figure 7;
Figure 9 is a cross-sectional view similar to Figure 5 but showing an
alternate form of base plate which also functions as a core plate; and
Figure 10 is a vertical cross-section similar to Figure 3 but showing
another embodiment of dished plate heat exchanger with a base plate
formed with an integral ridge.
In the detailed description which follows, various exemplary
embodiments are described, particularly with reference to the appended
figures. However, the particularly disclosed embodiments are merely
illustrative of heat exchangers constructed according to the present
disclosure.
Referring now to Figure 1, a conventional heat exchanger plate 10,
according to the prior art, comprises a rectangular plate bottom 12
surrounded on all sides by an upwardly and outwardly sloping edge wall
14. The plate 10 is fixedly mounted on a substantially rectangular base
plate 11. The bottom 12 constitutes a central main section of the plate 10
having a peripheral edge 16. The edge wall 14 extends outwardly from
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and around this peripheral edge at an acute angle indicated at A to a plane
defined by the main plate section-and the base plate 11. A heat exchanger
plate of this type is commonly known as a "dished" plate. The illustrated
bottom 12 is provided with four holes 18, 20, 22, and 24 near its four
corners, each of these holes able to serve as an inlet hole or an outlet hole
for a heat exchange fluid as required by the particular application. Two
holes 18 and 24 are raised relative to the plate bottom 12 and are formed
in raised bosses having flat upper surfaces 26 and 28 and circumferential
sidewalls 30 and 32. As can be seen from Figure 1, the raised holes 18
and 22 are spaced from the edge wall 14. The other two holes 20 and 22
are co-planar with the bottom 12. As shown, the hold 24 can be
effectively closed by the base plate if no fluid passage is required at this
location. If desired or if required, the plate 10 can be attached by brazing
to the base plate by means of a flat shim plate 13 in a known manner.
The shim plate, which initially can be coated with a brazing material, can
be approximately the same in size and shape as the central main section
of the plate 10.
A plurality of plates of the type shown in Figure 1 can be stacked on
top of one another to form a stacked plate heat exchanger as shown in
Figure 2. It will be understood that a plurality of dished-type plates such
as the plates 10' can be arranged in a stack to form a heat exchanging
core with fluid flow passages being provided between adjacent plates in
the stack. As illustrated, the plates 10' are stacked with their edge walls
14' in nested, sealed engagement. The raised holes 18', 24' of plate 10'
align with the two flat holes and the flat upper surfaces 26, 28 of the
raised holes 18', 24' are sealed to the bottom of an adjacent of plate 10'
around the peripheries of the flat holes including hole 22'. A flow passage
for heat exchange fluid is formed between the plate bottoms 12' of plates
10'. In order to enhance heat exchange efficiency, a fin or turbulizer 27 of
known construction may be provided in this flow passage. Also shown in
Figure 2 are a suitable metal reinforcement plate 29, a lid plate 31 having
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no fluid flow holes and closing the top of the upper core plate 10', and a
flat shim plate 13' connecting the core to the base plate 11'.
Figure 3 illustrates schematically a known method for mounting a
stacked plate heat exchanger. The heat exchanger 40 comprises a heat
exchanging core formed of a plurality of dish-type or dished plates 42
arranged in a stack with fluid flow passages 44 being provided between
adjacent plates in the stack. As in the embodiment illustrated in Figure 1,
each plate 42 comprises a main plate section or bottom 12 and an edge
wall 14 extending outwardly from and around the peripheral edge of the
bottom. For ease of illustration, the inlet and outlet holes provided through
the bottoms of the plates are not shown in Figure 3. In this heat
exchanger, the heat exchanging core is supported by a base plate 46
which is rigidly attached to one of the dish-type plates 42 located at one
end of the stack (as shown in Figure 3, this is the bottom plate 42').
Strengthening the connection between the adjacent or bottom core plate
and the base plate is a so-called belt 48 which extends about the
periphery of the adjacent plate 42'. Instead of a belt connection to attach
the core to the base plate, it is also possible to use a shim plate as shown
in Figures 1 and 2 or a_clouble core plate. A "double core plate" is a
construction wherein the end of the heat exchanger core is made of two
core plates arranged immediately next to each other both along their
central main sections and along their edgewalls and rigidly connected
together. The use of the belt or a double core plate (not shown)
strengthens the weakest location of this type of heat exchanger. In other
words, the weakest location of this type of heat exchanger is generally the
connection to the first or bottom core plate 42' when this particular core
plate does not have a double thickness relative to the other core plates 42.
However, a difficulty with a double core plate or a belt is that it increases
the amount of material used in the construction of the heat exchanger
compared, for example, to the use of a shim plate. Also, belts such as the
belt 48 can be difficult to manufacture and relative costly as the stamping
angle is greater than 90 degrees, which means that these belts need to be
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stamped in two directions. It will also be appreciated that these belts are
generally made from a single, flat metal plate with the center portion of
the plate being removed and not used. Thus, the amount of metal required
to make the belt is quite high.
As also shown in Figure 3, the known base plate 46 is generally
relatively thick, particularly when compared to the thickness of the core
plates 42. The base plate has been made thick in order to increase the
rigidity of this plate, which increases the strength of the connection
between the plate and the core. However, the use of a thick base plate
increases the overall weight of the heat exchanger and, of course,
increases the amount of material used in the construction of the heat
exchanger.
Figures 4 to 6 illustrate the construction of a bottom section of a
heat exchanger constructed in accordance with the present invention. This
bottom section includes a bottom end plate 43' which is at one end of a
heat exchanging core formed of a plurality of the dish-type plates 43
arranged in a stack with the fluid flow passages 44 being provided
between adjacent plates in the stack. Only the end plate 43' and the
adjacent plate 43 are shown for ease of illustration. The core is of known
construction. Each dished plate has a bottom or main plate section 12
having a peripheral edge 16 and an edge wall 14 extending outwardly
from and around the peripheral edge at an acute angle to the plane
defined by the bottom or main plate section. The inlet and outlet holes 18,
20, 22, 24 can be provided through the main plate sections of the plates
for passage of heat exchange fluids. If, for example, the heat exchanger
10 is intended as an oil heat exchanger, one of the heat exchange fluids
can be oil or a similar liquid while a second heat exchange fluid can be an
standard, known liquid used for cooling (or heating) oil. The plates 43, 43'
are in a nested seal engagement with one another and the main plate
sections of adjacent plates are spaced from one another to form the fluid
flow passages 44.
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In order to mount the heat exchanger 50, there is provided a metal
base plate 54. In an exemplary version of the heat exchanger, the plate
54 is substantially thicker than core plates 43, 43'. The normal range of
base plate thickness is between 1.5 and 4mm (0.060" to 0.160"). The
base plate 54 is rigidly attached to the dish-type plate 43' which is at one
end of the stack. The base plate is formed with an integral ridge 56
extending snugly along and adjacent the edge wall of the dish-type plate
43'. Sections of the ridge 56 or the entire ridge are spaced from adjacent
edges 58, 58' of the base plate so as to provide mounting flanges 60, 60'
for the heat exchanger. The base plate 54 can be made by a stamping
process.
The ridge 56 in an exemplary embodiment can have a U-shaped
transverse cross-section as shown in Figures 5 and 6. When the plate 54 is
formed by stamping, there is a minimum bending radius for the plate. For
aluminum, this minimum bending radius is usually lx thickness of the
plate. The ridge includes inner ridge wall 62 and outer ridge wall 64, with
these two walls in the illustrated exemplary version extending at an acute
angle to each other and to the vertical as seen in Figure 5. The inner ridge
wall 62 extends parallel to an adjacent outer surface 66 of the edge wall of
the adjacent core plate 43' and is attached directly thereto by brazing.
The illustrated exemplary ridge 56 is a continuous ridge that
extends around the perimeter of the end core plate 43', this continuous
ridge being shown in Figure 4. Thus the ridge has two parallel, opposite
sections 68 and 70, and two further parallel and opposite sections 72, 74.
However, instead of the continuous ridge as shown, the heat exchanger
can be formed with simply two ridge sections, for example, located on
opposite sides of the end core plate 43'. It is also possible to construct the
base plate with several, separate ridge sections which are not joined to
one another, for example, one section on each corner of the end core plate
43'. For some applications, the ridge may extend along only one side of
the heat exchanger, providing only one mounting flange located on one
side of the heat exchanger. =
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Figures 4 and 6 also illustrate fastener holes 80 formed in the
mounting flange or flanges. Bolts or rivets can extend through these holes
for the purpose of mounting the heat exchanger to an adjacent support
structure (not shown). Two such bolts 82 can be seen in Figure 4. It will
be appreciated that such holes can be provided in all four corners of the
base plate in an exemplary embodiment. Depending on packaging issues
and depending on the sealing requirements of the base plate 54, the
mounting-flanges can be displaced from the corners of the plate. In most
cases there are 3 to 5 holes 80 around the perimeter of the base.
Threaded fasteners in the form of screws can also be used instead of bolts
and nuts.
It will be appreciated that a very strong, permanent connection can
be formed between the base plate 54 and the adjacent core plate,
particularly by means of brazing, a technique for connecting stacked plates
well known in the heat exchanger art. The brazed connection is formed not
only along the inner ridge walls and the adjacent edge walls of the core
plate but also between the central main plate section 84 of the base plate
and the central main plate section of the end core plate.
An exemplary base plate 54 is made of 3003-aluminum. Other
possible aluminum materials for the base plate are 3000 series, 5000
series and 6000 series, such as 6061. When the base plate 54 is formed
by a stamping process, the process only requires stamping in one
direction. With the present mounting, the base plate can be a relatively
thin plate if desired (see Figure 9). When the base plate is made of a
thinner material, both the weight of the base plate itself is reduced and
the weight of the complete heat exchanger. The formation of the
continuous ridge on the base plate increases the rigidity of the base plate.
Figures 7 and 8 illustrate another embodiment of a base plate for a
stacked plate heat exchanger with an exchanger core formed of a plurality
of dished plates 43, 43' such as those shown in Figures 4 to 6. The base
plate 94 which has an integral ridge 56 formed thereon similar to the base
plate 54 of Figure 4. In addition, formed along two side edges of the base
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plate is a peripheral lip or rib 96 which provides additional rigidity to the
base plate. It will be understood that this lip can extend about the entire
periphery of the base plate, if desired or it can be provided on one or three
side edges if this will provide the necessary rigidity. The peripheral lip 96
as shown extends substantially perpendicular to the plane defined by the
planar central section of the base plate. However, it is possible for the
peripheral lip to extend at a different angle from that shown. For example
the lip can extend at an acute angle to the adjacent flange section of the
base plate. Instead of using a lip 96, the base plate can also be
strengthened by using an additional U-shaped ridge similar to the ridge 56
or a V-shaped ridge (see Figure 9 for example). Figures 7 and 8 also
illustrate the provision of fluid flow holes 95, 97 and 99 in the central
section of the base plate which can be inlet and outlet holes for the heat
exchange liquids (i.e. oil, coolant). Note that four holes are required in
the overall heat exchange for the inlet and outlet for the first liquid (for
example, oil) and for the inlet and outlet for the second liquid (for
example, coolant). Each of these holes can be either in the base plate or
the top plate, depending on the packaging. In the case of an engine oil
heat exchanger, the oil or coolant sometimes comes from galleries inside
the engine directly to the base plate. In other cases, the oil and/or
coolant flows through hoses to a fitting located on the top plate or
sometimes the base plate.
A further embodiment of heat exchanger formed from a stack of
dished plates is illustrated in Figure 9. This heat exchanger 100 is similar
to the heat exchangers desired above in connection with Figures 4 to 6
except for the differences explained hereinafter. The main portion of its
core 92 is formed of a series of similar or identical dished plates 43. The
base plate 102 is formed from thicker metal plate which can, in an
exemplary embodiment, be aluminum alloy. In this embodiment, the plate
102 also provides a first core plate for the heat exchanger. Thus, there is a
fluid flow passage 44 formed between the plate 102 and the adjacent core
plate 43. With this embodiment, there is still a saving of material since the
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base plate also provides the-first core plate. An integral ridge 110 similar
to that in the embodiments of Figures 4 and 6 is provided on the base
plate and it can be brazed to the edge wall of the adjacent plate 43.
However, the ridge 110 has a V-shaped cross-section throughout its length
as shown. The V-shape is inverted when the base plate is positioned at =
the bottom of the heat exchanger as shown. If desired and, in order to
strengthen the connection between the base plate and the adjacent plate
43, the height of the inner ridge wall 111 can be increased so as to extend
the entire height of the adjacent edge wall.
Figure 10 illustrates yet another embodiment of a heat exchanger
constructed in accordance with the present disclosure. This heat
exchanger 120 is also formed of a stack of dished plates 43 and has a
base portion similar to that illustrated in Figures 4 to 6 except for the
differences noted hereinafter. Its base plate 122 is formed from a
relatively thin metal plate which can, for example, be similar in thickness
to the dished plates. One exemplary material for the base plate 122 is
3003-aluminum. The bottom end plate 43' which is at one end of the heat
exchanging core is rigidly attached such as by brazing to the base plate.
In this embodiment, the base plate is formed with an integral V-shaped
ridge 124 which extends along and is immediately adjacent to the edge
wall of the dish-type plate 43'. Again sections of the ridge or the entire
ridge are spaced from adjacent edges 124, 126 of the base plate so as to
provide mounting flanges for the heat exchanger. In a particular
exemplary embodiment (and as better shown in Figures 4 and 6) the
mounting flanges are provided at the corners of the base plate.
Although the core plates 43, 43' are shown with substantially flat,
central main plate sections, it will be understood by those skilled in the
heat exchanger art that the main plate sections can be provided with ribs,
corrugations, dimples or other protrusions to enhance heat exchange
efficiency by forcing the heat exchange fluid to flow a tortuous path
through the fluid flow passages 44.
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It will also be understood that it is possible to construct the heat
exchangers of the present invention by means of a single brazing step
after the core plates are stacked together with the base plate. Thus, these
heat exchangers can be manufactured in an efficient manner and at a
reasonable cost.
The heat exchanger construction described herein can also be used
for stainless steel heat exchangers, whether copper or nickel brazed. In
such heat exchangers, the base plate can be made of stainless steel or
steel. One form of stainless steel that can be used is 304 SS.
While the present invention has been illustrated and described as
embodied in several exemplary embodiments, i.e. embodiments having
particular utility in heat exchanger applications, it is to be understood that
the present invention is not limited to the details shown herein, since it
will
be understood that various omissions, modifications, substitutions and
changes in the forms and details of the disclosed heat exchangers and
their operation may be made by those skilled in the art without departing
in any way from the scope of the present invention. For example, those of
ordinary skill in the art will readily adapt the present disclosure for
various
other applications without departing from the scope of the present
invention.
