Heat exchangers having high durability

A heat exchanger having a plurality of heat exchanger plate pairs. Each plate has a longitudinal central planar portion and a peripheral edge portion extending from it. The plate is provided with a first boss and a second boss having an inlet and outlet, respectively. A rib is also provided extending from the peripheral edge portion to the central planar portion, the rib having a mating surface, where the rib mating surface of a first plate in a first plate pair is in contact with a rib mating surface of a second plate in an adjacent plate pair.

FIELD

This specification relates to heat exchangers, and in particular to stacked plate heat exchangers, as used particularly in the automotive industry.

BACKGROUND

Stacked plate heat exchangers typically comprise a plurality of plate pairs stacked one on top of the other with each plate pair having opposed inlet and outlet openings such that when the plate pairs are stacked together, the inlet and outlet openings align to form inlet and outlet manifolds and thereby establish communication between fluid channels formed inside each plate pair. The plate pairs are usually joined together by brazing. However, as the plate pairs tend to be unsupported in the area of the manifolds, the heat exchanger in the area of the inlet and outlet openings tends to distort under the pressure of the fluid flowing therethrough and will often expand like an accordion or “bellows” in the manifold region. The distortion that occurs in the manifold regions of the heat exchanger tends to lead to premature failure or cracking and leaking in the heat exchanger.

Similarly, in in-tank oil coolers (ITOC) (cross-section of a portion of an ITOC is shown inFIG. 1), under internal oil pressure, the header expands primarily due to the force acting on the unsupported area of the bottom plate. Although turbulizers are present in the channel (though not shown inFIG. 1), the turbulizers end at the header bubble, and hence can only provide limited support to the header region. This expansion, similar to how a bellows would expand, leads to eventual failure in the core plate bubble under high pressure. This failure location is typically located either in the top or bottom channel due to the change in local stiffness because of the presence of the fitting and bottom reinforcement plate.

For applications that require higher durability, the core plate bubbles are replaced with washers (also referred to as spacers) as shownFIG. 2. The higher durability is achieved not only by the elimination of the bubbles but by extending the washer diameter such that it overlaps the area of the core plate to which the turbulizer brazes. This increases the vertical rigidity of the header region, making is less susceptible to vertical expansion under pressure. The drawback to such a design is that it makes it more complicated for assembly and increases the final cost of the part.

Another approach used to reinforce the inlet and outlet areas of a heat exchanger is to use exterior clamps or brackets that are brazed to the outside of the heat exchanger to keep it from expanding under pressure. Another further approach is to insert perforated or slotted tubes through all of the aligned inlet and outlet openings of each plate, the tubes being brazed to the peripheries of the respective inlet and outlet openings. However, such approaches as described above, can be costly and can increase overall manufacturing process and costs associated with the particular heat exchanger.

U.S. Pat. No. 5,794,691 (Evans et al.) discloses a heat exchanger made from a plurality of stacked plate pairs wherein the inlet and outlet openings that form the manifolds include opposed flange segments formed on the inner peripheral edges of the openings. The flange segments extend inwardly and are joined together when the plates are stacked together to prevent expansion of the manifolds when under pressure.

U.S. Pat. No. 8,678,076 B2 (Shore et al.) discloses a plate type heat exchanger having a plurality of stacked plate pairs. Each plate pair has opposed manifold members with respective inlet and outlet openings that are in registration to form respective inlet and outlet manifolds for the flow of a first fluid through a first set of fluid channels formed by the plate pairs. The manifold members spacing the plate pairs apart to form a second set of transverse flow channels for the flow of a second fluid. Each plate has a peripheral edge portion which seals the plates together to form the first set of fluid channels therebetween. A protrusion member is formed proximal to each of the manifold members, each protrusion member having a mating surface such that the protrusion members on the second plate of one plate pair align and abut with the protrusion members on the first plate of an adjacent plate pair thereby reinforcing and strengthening the manifold region of the heat exchanger to prevent the deformation or accordion of the manifold under pressure.

There is a need in the art for heat exchanger plates that can help to form a rigid structure along the height of the heat exchanger that allows the bottom and top core plates to better withstand the pressure load of a fluid flowing therethrough. In addition, there is a need in the art for a heat exchanger plate that can to eliminate the need to use washers between core plates in the header region and to increase the burst strength of the heat exchanger. Further, there is a need in the art for a heat exchanger having such heat exchanger plates.

SUMMARY OF INVENTION

In one aspect, a reinforcing rib is formed in the header portion (inlet and outlet manifolds) of the heat exchanger plate. In particular, the reinforcing rib is positioned between a boss having the inlet (or outlet) and the peripheral edge of the heat exchanger plate. Preferably, the reinforcing rib extends from the central planar portion of the heat exchanger plate around the boss having the inlet (or outlet) to the peripheral edge portion of the heat exchanger plate, with the reinforcing rib being in contact with the peripheral edge portion.

In another aspect, a heat exchanger plate pair is disclosed having the reinforcing rib as described above.

In another further aspect, the heat exchanger plate pair is disclosed having the reinforced rib as described herein and a turbulizer positioned in a fluid channel defined by the plate pair. The turbulizer extending from one peripheral edge portion of the heat exchanger plate having the inlet (from the narrow edge of the longitudinal heat exchanger plate) to the opposing peripheral edge portion of the heat exchanger plate (to the other the narrow edge of the longitudinal plate) having the outlet. In a particular embodiment, the turbulizer has an aperture, with the edge of the aperture being generally aligned with the edge of the inlet (or outlet).

In still another aspect, the specification relates to a heat exchanger having a heat exchanger plate pair with the plate having the reinforcing rib as described above. The heat exchanger is also provided with a fitting that engages the inlet and outlet of the heat exchanger. Further, the peripheral edge portion of the fitting also engages the reinforcing rib of the top heat exchanger plate to help provide a more rigid structure along the height of the heat exchanger.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 3discloses a plan view of a heat exchanger plate2in accordance with an embodiment disclosed herein. The heat exchanger plate2has a central planar portion4. In the embodiment shown, the heat exchanger plate2is generally rectangular; however, other shapes are also possible depending upon design and application requirements. The heat exchanger plate2has a longitudinal central planar portion4, that has a first end6, a second end8, a third end10and fourth end12; which relate to the different sides of the heat exchanger plate2. Hence, the first end6and second end8are opposed to each other and are at the narrow edge of the heat exchanger plate2. Similarly, the third end10and fourth12are also opposed to each other, and extend from the first end6to the second8. The third end10and the fourth end12therefore define the longitudinal edge of the central planar portion4.

The heat exchanger plate2is also provided with a peripheral edge portion14that extends from the longitudinal central portion4on all sides of the heat exchanger plate2. Hence, the peripheral edge portion14extends from the first end6, the second end8, the third end10and the fourth end12of the longitudinal central planar portion4. As is described herein, the peripheral edge portions14of two plates come in contact to form a plate pair, when the plates2are positioned in a face-to-face relationship, and help define a fluid channel. To achieve this, the peripheral edge portion14is present in a different plane than the central planar portion4of the heat exchanger plate2. For instance, the peripheral edge portion14can be considered to be below the central planar portion4. For purposes of description, the central planar portion is present in first plane, while the peripheral edge portion14is present in a second plane.

The heat exchanger plate2has a first boss (or bubble)16near the first end6of the central planar portion4. The first boss16extends in a direction opposite to the peripheral edge portion14. In one embodiment, as shown in the figures, the first boss16has a generally flat surface, denoted herein as a first boss contact surface18, which lies in a different plane (third plane) than the central planar portion4and the peripheral edge portion14. When viewed from the side, in one view of the heat exchanger plate2, the central planar portion4(that lies in the first plane) is in between the peripheral edge portion14(that lies in the second plane) and the first boss contact surface18, which lies in the third plane. The first boss contact surface18has inlet opening20to permit fluid to enter into the heat exchanger22. As described herein, the first boss contact surface18engages the contact surface of a boss on an adjacent plate pair to form the inlet manifold.

In addition to the above, the heat exchanger plate2also has a second boss (or bubble)24near the second end8of the central planar portion4. Like the first boss16, the second boss24extends in a direction opposite to the peripheral edge portion14(and in the same direction as the first boss16). Similar to the first boss16, the second boss24has a generally flat surface, denoted herein as a second boss contact surface26, which also lies the third plane (same as the first boss contact surface18). The second boss contact surface26has outlet opening28to permit fluid to exit from the heat exchanger22. As described herein, the second boss contact surface26engages the contact surface of a boss on an adjacent plate pair to form the outlet manifold.

In accordance with an embodiment disclosed inFIG. 3, the heat exchanger plate2is provided with a first reinforcing rib30at the first end of the central planar portion4(denoted herein as the first end first reinforcing rib). The first reinforcing rib30extends from the central planar portion4at the first end6in the same direction as the first boss16, and is coupled to the peripheral edge portion14. In other words, the first end first reinforcing rib30extends from the peripheral edge portion14at the first end6to the central planar portion4. In one embodiment, as disclosed herein, the entire reinforcing rib30is in contact with the peripheral edge portion14, while in other embodiments, only a portion of the reinforcing rib30is in contact with the peripheral edge portion14.

The first end first reinforcing rib30is also provided with a first end first rib mating surface32. The first end first rib mating surface32also lies in the third plane, with the first boss contact surface18and the second boss contact surface26. When the heat exchanger22is assembled, the rib30on one plate engages a rib30on another plate in an adjacent plate pair. This can help to reinforce the header section of the heat exchanger22.

Also provided (as shown inFIG. 3) a second end first reinforcing rib34at the second end8of the central planar portion4(denoted herein as the second end first reinforcing rib). The second end first reinforcing rib34extends from the central planar portion4at the second end8in the same direction as the second boss24, and is coupled to the peripheral edge portion14. In other words, the second end first reinforcing rib34extends from the peripheral edge portion14at the second end8to the central planar portion4. The second end first reinforcing rib34is also provided with a second end first rib mating surface36. The second end first rib mating surface36also lies in the third plane, with the first boss contact surface18and the second boss contact surface26. Analogous to the first end first reinforcing rib30, when the heat exchanger22is assembled, the second end rib34on one plate engages a second end rib34on another plate in an adjacent plate pair.

FIG. 4shows a cross-sectional perspective view of a header portion of a heat exchanger plate pair in accordance with the specification. As shown, the plate pair is formed by a first plate38and a second plate40that are positioned in a face-to-face relationship. The peripheral edge portions14of the two plates (first plate38and second plate40) come in contact to define a first fluid flow channel42that permits a fluid entering the inlet20to flow through the plate pair. Typically, as should be known to a person of ordinary skill in the art, the first plate38is identical to the second plate40, although in some embodiments they may be different.

In a particular embodiment, as shown inFIG. 4, the heat exchanger plate2is provided with dimples44that can help to provide further structural support to the heat exchanger plate2. The number, position and size of the dimple44is not particularly limited and can vary depending upon design and application requirements. In one embodiment, for example as shown inFIG. 4, the dimple44is positioned close to the boss (first boss16or second boss24). In another embodiment, as described herein, multiple dimples44are provided.

FIGS. 5 and 6show cross-sectional views of a header portion of further embodiments of heat exchangers22in accordance with the specification. The heat exchanger22is provided with a plurality of heat exchanger plates2. Each plate2of the plate pair is present in a face-to-face relationship, with the plate pairs together defining the first fluid flow channel42. Adjacent plate pairs are spaced apart from one another and define a second fluid flow channel46for flow of a second fluid, with which heat exchange takes place.

As described herein, particularly with respect toFIGS. 3 and 4, the heat exchanger22is provided with heat exchanger plates pairs2having a first plate, where the peripheral edge portion14of the first plate engages with the peripheral edge portion of the second plate in the plate pair. The heat exchanger plates2are also provided with reinforcing ribs30that can help to provide strength and rigidity in the header portion of the heat exchanger22. The reinforcing ribs30have a reinforcing rib mating surface32, where the reinforcing rib mating surface32of a first plate engages with the reinforcing rib mating surface32of a second plate of an adjacent plate pair (as shown inFIGS. 5 and 6).

As more clearly shown inFIG. 5, dimples44are also provided on the central planar portion4. Similar to the reinforcing rib mating surface32, the dimples44of a first plate engage with dimples44of a second plate of an adjacent plate pair.

In one embodiment, as shown inFIG. 5, the heat exchanger plate pairs are provided with a turbulizer48. Although,FIGS. 5 and 6only show a turbulizer48present in the top plate pair, as should be recognized a person of ordinary skill in the art, a plurality of plate pairs can be provided with the turbulizer48or a all the plate pairs can be provided with the turbulizer48. In accordance with an embodiment disclosed herein, the design of the heat exchanger plate2and the presence of the reinforcing ribs30, allows the turbulizer48to extend all the way to the first end6(or second end8) of the heat exchanger plate pair. This allows the turbulizer48to be present in between the space defined by the reinforcing ribs30in a plate pair, and also contact the internal surface of the heat exchanger plate pair that extends to form the peripheral edge portion14.

The heat exchanger22also has a fitting50that couples to a top heat exchanger plate2. In one embodiment, the top plate and/or the bottom plate of the heat exchanger is a flat plate. In other words, a plate lacking the reinforcing ribs disclosed herein. Alternatively, in another embodiment, the top plate and/or the bottom plate of the heat exchanger can have the reinforcing ribs as disclosed herein. The fitting50has an orifice54that is in fluid communication with the inlet20(or outlet28) of the top heat exchanger plate2. In one embodiment, as shown inFIGS. 5 and 6, the fitting50has a peripheral edge portion that engages the reinforcing rib30of the top heat exchanger plate2. Alternatively, the fitting50of the heat exchanger22is designed to allow the reinforcing ribs30to be within the perimeter of the fitting50; which can help with further reinforcement of the heat exchanger22. In one embodiment, as shown inFIGS. 5 and 6, the peripheral edge portion52of the fitting50overlays the reinforcing ribs30on the first end of heat exchanger plates (with or without the flat heat exchanger plate in between). In another embodiment, the peripheral edge portion52of the fitting50overlays the reinforcing ribs30on the first end, the third end and the fourth end of heat exchanger plates (with or without the flat heat exchanger plate in between).

FIG. 7shows cross-sectional top perspective view of a header portion of a heat exchanger without the top plate in accordance with an embodiment disclosed herein. As can be seen, the turbulizer48extends all the way to the first end6of the central planar portion4of the heat exchanger plate2. Moreover, turbulizer48also extends to the second end8, third end10and fourth end12of the central planar portion4; and can be near or in contact with the inner wall of the heat exchanger plate pairs that extend to form the peripheral edge portion14. In a particular embodiment, as shown inFIG. 7, the turbulizer48has an aperture56, where the edge of the aperture56is generally aligned with the edge of the first boss defining the inlet20(or outlet) of the heat exchanger plate2; thus allowing fluid to flow through the inlet20.

FIG. 8shows cross-sectional side views of header portions of an embodiment of a (a) heat exchanger in accordance with the specification, and (b) a heat exchanger having washers in between plate pairs. The heat exchanger22(FIG. 8a) is similar to the heat exchanger22shown inFIG. 5. As seen in theFIGS. 8aand 8b, a turbulizer48is present in all plate pairs forming the heat exchanger22. Further, in the embodiment shown inFIG. 8b, a washer58is provided between plate pairs to further enhance the strength of the header section of the heat exchanger22. The heat exchanger22shown inFIG. 8acan help to prevent deformation of the header portion analogous to the heat exchanger (FIG. 8b) having the washer. However, as shown inFIG. 8, the presence of the reinforcing ribs16can significantly help to reduce the pressure sensed at the peripheral edges of the plate pairs near the inlet and outlet. As fluid enters through the fitting inlet, the highest pressure is sensed by the upper plate pairs, with the pressure sensed by the plate pairs diminishing as the fluid flows down in the fluid inlet manifold. With the lowest plate pair being noted as zero pressure, for purposes of reference, as shown inFIG. 8a, the pressure sensed by the top plate pair of the heat exchanger having reinforcing ribs16has a magnitude of 0.5752. In contrast, the pressure sensed by the top plate pair of the heat exchanger having washers (FIG. 8b) ranges from 0 to 1.06. Hence, the presence of the reinforcing ribs16can significantly reduce the pressure on the plate pairs and help to avoid deformation of the plate pairs near the inlet manifold.

FIG. 9shows top plan views of a portion of a heat exchanger plate showing different embodiments of reinforcing ribs30in accordance with the specification. In one embodiment, as shown inFIGS. 9a-9d, the reinforcing ribs30have a generally U-shaped structure. In such embodiments, the reinforcing rib30is also in contact with the third end10and fourth end12of the heat exchanger plate2. Hence, in one embodiment, the first end first reinforcing rib30also extends from the peripheral edge portion14at the third end to the central planar portion4.

In an alternate embodiment, as shown inFIG. 9e, the reinforcing rib30can be formed along the length of the first end6of the central planar portion4, from the third end10to the fourth end12. Alternatively, the reinforcing rib30can have an arcuate profile as shown inFIG. 9f, with the rib30extending from the peripheral edge portion14inwards in the on the central planar portion4. In the embodiment shown ifFIG. 9f, the concave face of the rib30is towards the peripheral edge portion14, however, as should be recognized, this can be reversed with the concave face towards the first boss.

The reinforcing rib30can be formed as a single rib as shown inFIGS. 9a-9cand 9e. Alternatively, the reinforcing rib is formed by a plurality of rib portions as shown inFIGS. 9dand 9f, which together function to provide the reinforcement. Furthermore, a reinforcing rib30can also be provided at the second end8of the central planar portion4. The reinforcing ribs30on the first end6can be the same or different from the reinforcing ribs30at the second end8.

The heat exchanger disclosed herein helps to increase the vertical rigidity of the header region, making is less susceptible to vertical expansion under pressure; while also helping to avoid use of washers.

In addition, the extended turbulizer can help to increase the oil side stiffness of the channels. The rib can help to increase the coolant side stiffness with the additional braze contact around the perimeter of the core plate under the fitting, eliminating the forcing moment that is applied to the core plate bubble as the bottom plate is pushed downwards by the oil pressure. The reaction force from the downward force of the oil is now transmitted up through the header to the fitting, and the overall effect is to reduce the deformation in the heat exchanger (as shown inFIG. 8) and lowering the stress.

Another benefit of this design is that it can help to reduce the oil side pressure drop. With the additional support provided by the rib, the internal diameter (ID) of the header bubble can be reduced as well. Having this diameter match the fitting diameter eliminates the pressure loss associated with sudden changes in cross sectional area of the flow path. Therefore, such heat exchangers22can also have a lower oil side pressure drop than conventional designs for the same turbulizer design.

PARTS LIST

No.Description2Heat exchanger plate4central planar portion6first end of central planar portion8second end of 410a third end of 412fourth end of 414peripheral edge portion16first boss18first boss contact surface20inlet opening22Heat exchanger24Second boss26Second boss contact surface28Outlet opening30Rib32first end first rib mating surface34second end first reinforcing rib362ndend first rib mating surface38first plate40second plate42first fluid flow channel44Dimple46Second fluid flow channel48Turbulizer50Fitting52Fitting peripheral edge portion54Orifice56Aperture58Washer