This invention related to heat exchangers, and in particular to stacked plate heat exchangers as used particularly in the automotive industry.
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.
One 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 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. Yet another common approach is to use a large area washer or reinforcing plate to space the plate pairs apart and to create the fluid communication between the fluid channels formed by the plate pairs. The additional surface area provided by the large area washer or reinforcing plate provides additional support to the typically unsupported area between plate pairs; however, these types of washers can be costly and therefore increase overall manufacturing 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.
In the present invention, a protrusion member is formed in the peripheral region of the plates of a stacked-plate heat exchanger in proximity to the manifold region to improve the overall ability of the manifold to withstand the high fluid pressures that are frequently encountered in these types of heat exchanger systems as well as to improve the overall efficiency of the heat exchanger by preventing undesirable bypass flow.
According to one embodiment of the invention, there is provided a heat exchanger comprising a plurality of stacked plates arranged in face-to-face plate pairs. Each of the plate pairs includes first and second plates, the first plate having a central planar portion, and a peripheral edge portion extending from the central planar portion to an outer edge. The second plate of each face-to-face plate pair having a central planar portion spaced apart from the central planar portion of the first plate, a peripheral edge portion extending from the central planar portion to an outer edge, the peripheral edge portion of the second plate mating with the peripheral edge portion of the first plate thereby defining a first set of fluid channels between the spaced-apart central planar portions for the flow of a first fluid therethrough. Opposed manifold members space apart one plate pair from an adjacent plate pair and establish fluid communication between the first set of fluid channels formed between the spaced-apart central planar portions in each of the plate pairs thereby forming respective inlet and outlet manifolds. The manifold members being inwardly disposed from respective ends of the first and second plates and further defining a second set of fluid channels between adjacent plate pairs for the flow of a second fluid through the heat exchanger, the second set of fluid channels being transverse to the first set of fluid channels. The first and second plates further including a protrusion member located proximal to each of the manifold members. The protrusion member being spaced-apart from the respective manifold member by a predetermined distance and having a mating surface so that the protrusion members on the second plate of one plate pair align and mate with the protrusion members of the first plate of the adjacent plate pair when said plate pairs are stacked together thereby supporting said plate pairs in their spaced-apart relationship.
Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Referring to the drawings, there is shown in
While the inlet and outlet fittings 28, 30 are shown as being mounted in the top plate 20, it will be understood that the inlet and outlet fittings 28, 30 could instead be mounted in the bottom plate pair 16 with the top plate 20 of the top plate pair 14 serving to close the heat exchanger. In another configuration, the top plate 20 and bottom plate 26 could be formed so that one fitting is mounted in the top plate 20 and the other fitting mounted in the bottom plate 26. Accordingly, various configurations of the heat exchanger 10 are contemplated and can be adjusted depending on the particular application or design requirements.
Referring now to
When the plate pairs 12 are stacked together, they are spaced-apart from each other by means of manifold members 37. The manifold members 37 are typically located at opposed ends of the heat exchanger plates 18, 19, and are inwardly disposed from the ends thereof. The manifold members 37 establish fluid communication between the first set of fluid channels 36 formed between the central planar portions 34 of the plates 18, 19 in each of the plate pairs 12, thereby forming respective inlet and outlet manifolds 42, 44 for the flow of the first fluid through the heat exchanger 10. The flow of the first fluid through the heat exchanger is diagrammatically represented in
As mentioned above, the manifold members 37 also space the plate pairs 12 apart when they are stacked together and thereby form a second set of flow channels 39 between the plate pairs 12 for the flow of a second fluid through the heat exchanger 10, the second set of flow channels 39 being transverse to the first set of flow channels 36. In the case where the heat exchanger 10 is used as an oil cooler, it will be understood that the first fluid would be engine or transmission oil, for example, while the second fluid would be water or any other suitable coolant such as ethylene glycol. It will also be understood that heat exchanger 10 may be used for applications other than as an oil cooler. Accordingly, the first and second fluids could be any of a number of fluids. For example, applications are contemplated wherein the first fluid is water or coolant, while the second fluid is air.
In the subject embodiment, the manifold members 37 are in the form of spaced-apart end bosses 38 which are integrally formed in the central planar portions 34 of each of the plates 18, 19. As shown, the end bosses 38 are raised out of the plane of the corresponding central planar portion 34 and have openings 40 formed therein for providing fluid access to the fluid channels 36 formed between the spaced-apart central planar portions 34 of the plates 18, 19. Therefore, when the plate pairs 12 are stacked together to form the heat exchanger 10, the end bosses 38 and their openings 40 align and are in fluid communication with each other thereby forming the inlet and outlet manifolds 42, 44. While manifold members 37 in the form of end bosses 38 are discussed in connection with the subject embodiment, it will be understood that many different forms of manifold members 37 may be used in connection with the subject invention. For instance, manifold members 37 in the form of washers, tubular members, spacing plates, etc. may be used. Some of these structures will be further described below in connection with additional example embodiments of the present invention.
As shown in
Cooling fins (not shown) could be located in the second set of flow channels 39 formed between adjacent plate pairs 12. The cooling fins that are typically used are corrugated cooling fins having transverse undulations or louvres formed therein to increase heat transfer. However, any type of cooling fin could be used in the present invention or even no cooling fin at all, if desired.
The structure of the first and second plates 18, 19 that make up plate pairs 12 of the subject embodiment will now be described in further detail. As shown more clearly in
As shown more clearly in
In the embodiment shown in
The half-dimple 57 has a generally flat mating surface 58 which, in this embodiment, lies in the same plane as the raised end bosses 38 of the plates 18, 19. Accordingly, when the plates 18, 19 are stacked in their face-to-face relationship, the half-dimples 57 on each plate 18, 19 align in such a way that they project in opposite directions. Therefore, when the plate pairs 12 are stacked together to form the heat exchanger 10, the mating surface 58 of the half-dimple 57 on the second plate 19 of a first plate pair 12 comes into surface-to-surface contact with the mating surface 58 of the half-dimple 57 on the first plate 18 of the adjacent plate pair 12 (see
When the stacked plate pairs 12 are joined together by brazing, for example, the mating half-dimples 57 or protrusion members 56 provide an additional area of surface contact between the adjacent plate pairs 12 in the unsupported area of the stacked plate pairs 12. The additional surface contact between the plate pairs 12 provides an additional brazing surface between the plate pairs 12 proximal to the manifold regions (i.e. the inlet and outlet manifolds 42, 44). The added surface area for brazing located proximate to the manifolds 42, 44 provides additional support to the end portions 48 of the plate pairs 12 which strengthens the structure of the heat exchanger 10 in a region that is typically prone to failure or cracking. As well, the external position of the protrusion members 56 allows for a visual check or inspection during the manufacturing process to ensure that a proper joint between protrusion members 56 has been achieved between the plate pairs 12 after brazing. Therefore, any flaws or defects with the connection between the protrusion members 56 can be easily detected as the additional brazing surface is located on the outside of the heat exchanger 10, thereby increasing the overall quality control associated with the manufacture of the heat exchanger 10.
While the half-dimple 57 type of protrusion member 56 has been described as having a generally flat mating surface, it has been found that initially forming the half-dimple 57 in the plates 18, 19 with a slightly rounded or dome-shaped mating surface 58 tends to facilitate the brazing process as the mating surfaces 58 will deform or compress under loading and collapse to a flat surface during the brazing process. Therefore, it will be understood that reference to the generally flat mating surfaces 58, is intended to encompass an initially rounded surface that deforms or collapses to flat during the manufacturing process.
Referring now to
Once again, the ribs 66 are spaced the predetermined distance D from the outer edge of the corresponding manifold member 37 or end boss 38 so as to ensure the optimal relationship between providing adequate support to the manifold region of the heat exchanger while ensuring that a sufficient amount of peripheral edge portion 54 is provided to form a proper seal between the plates 18, 19.
As in the embodiments described above, the plate 68 has peripheral edge portion 32 and central planar portion 34 which, for this plate, projects below the plane of the peripheral edge portion 32. As in the previously described embodiments, the manifold members 37 that space the plate pairs 12 apart and establish fluid communication between the fluid channels 36 formed therein are in the form of spaced-apart end bosses 38 (only one shown) formed at either end of the central planar portion 34 of the plate 68 and extend out of the plane thereof. The end bosses 38 have openings 40 formed therein for providing fluid access to the first set of fluid channels 36. In this embodiment, the peripheral edge portions 32 have protrusion members 56 in the form of stepped-flange extensions 70 extending from the outer edge 50 of the peripheral edge portion 32. The stepped-flange extensions 70 have a vertical portion 72 extending from the edge of the peripheral edge portion 54, and an outwardly extending flange portion 74 which is generally perpendicular to the vertical portion 72 and lies generally in the same plane as the manifold members 37 or end bosses 38. As
While the outwardly extending flange portion 74 of the stepped-flange extension 70 has been described as being generally perpendicular to the vertical portion 72, it has been found that forming the stepped-flange extensions 70 so that the flange portion 74 is slightly angled with respect to the vertical portion 72 so that they contact each other at their outer periphery when the plates 67, 68 are initially stacked together to form the plate pairs 12. The slightly angled flange portion 74, which is sometimes referred to as a sprung flange, will deform to a flat or perpendicular condition with respect to the vertical portion 72 under loading, which tends to increase the likelihood of forming a proper joint between the stacked plate pairs 12 when the plate pairs 12 are joined together.
As well, the stepped-flange extensions 70 on the first and second plates 67, 68 have been shown in
Incorporating protrusion members 56 in the form of stepped-flange extensions 70 is favourable not only for the advantage of providing additional support to the previously unsupported areas of the plate pairs, but this type of protrusion member 56 also tends to facilitate manufacturing processes and material requirements for producing heat exchanger plates incorporating the manifold strengthening protrusion.
In yet another embodiment of the present invention, the protrusion members 56, whether they be in the form of half-dimples 57, ribs 66 or flange extensions 70, can be formed with corresponding locating features to facilitate the proper alignment of the plate pairs 12 when they are stacked together to form the heat exchanger 10. More specifically, as shown in
While the above-described embodiments of the present invention have been described in connection with heat exchangers formed mainly of stacked, flanged plates, the present invention can also be incorporated into heat exchangers having what is commonly referred to as a pan and cover design, as will be described in further detail below.
Referring now to
First plate 104 has a central planar portion 108 and a peripheral edge portion 110 extending around the periphery of the plate 104 from the central planar portion 108 to an outer edge 111 of the plate 104. In this embodiment, the peripheral edge portion 110 is downwardly depending with respect to the central planar portion 108 of the plate 104 and is substantially perpendicular thereto. Second plate 106 is similar in structure to the first plate 104 and, therefore, also has a central planar portion 108 and a peripheral edge portion 110 extending from the central planar portion 108 to the outer edge 111 of the plate 106. However, as second plate 106 is positioned upside down with respect to the first plate 104, the peripheral edge portion 110 projects upwardly with respect to the central planar portion 108 of the plate 106, as shown. Second plate 106 is formed so as to be slightly smaller in size than first plate 104. Therefore, when the plates 104, 106 are stacked together in their face-to-face relationship, the peripheral edge portion 110 of the first plate 104 fits over and overlaps the peripheral edge portion 110 of the second plate 106. Accordingly, the second plate 106 acts as the “pan” while the first plate 104 acts as the “cover” which gives rise to the heat exchanger configuration commonly referred to as a “pan and cover” style heat exchanger.
The surface contact between the peripheral edge portions 110 of the first and second plates 104, 106 creates a seal between the plates 104, 106 when they are joined or brazed together, thereby forming the first set of fluid channels 36 therebetween. As described in connection with the previous embodiments, a turbulizer 46 may be positioned inside the plate pairs 102 in fluid channels 36.
As with the embodiments described above, each plate 104, 106 is formed with manifold members 37 in the form of end bosses 112 located at the respective ends 110 of the first and second plates 104, 106. The end bosses 112 are raised out of the plane of the central planar portion 108 of the corresponding plate 104, 106 so that when the plate pairs 102 are stacked together the end bosses 112 space the adjacent plate pairs 102 apart forming the second set of flow channels 39 therebetween. Each end boss 112 has an opening 114 formed therein; therefore, when the plate pairs 102 are stacked together, the end bosses 112 and openings 114 align so as to define respective inlet and outlet manifolds. While the subject embodiment of the heat exchanger 100 has been shown having circular end bosses 112 with circular inlet/outlet openings 114, it will be understood that any shape of end boss or opening may be used, as desired.
Although not shown in the drawings, heat transfer enhancing devices such as cooling fins or turbulizers, for example, may be positioned in the second set of flow channels 39 between the plate pairs 102, as described above in connection with the previous embodiments.
The end bosses 112 are formed in the respective end portions 118, shown by the encircled area in
A protrusion member 56 is formed in the end section 124 of the central planar portion 108 that extends around the end boss 112, the protrusion member 56 being appropriately spaced-apart from the end boss 112 by distance D. In the embodiment shown, the protrusion member 56 is in the form of a curvilinear rib 128 that projects out of the plane of the central planar portion 108, 124 and, generally corresponds to the shape of the end boss 112. When the plate pairs 102 are stacked together, the protrusion member 56 or rib 128 on the second plate 106 of a first plate pair 102 aligns with and comes into surface-to-surface contact with the protrusion member 56 or rib 128 on the first plate 104 of the adjacent plate pair 102. As with the embodiments discussed above, the mating of the protrusion members 56 or ribs 128 provide an additional area of surface contact between the adjacent plate pairs 102 proximate to the manifold regions, which area would otherwise be unsupported leaving the manifold regions susceptible to deformation (i.e. accordion or bellows-like deformation) when subjected to high pressure cycles.
While the above-described embodiments of the present invention have been described in connection with heat exchangers formed mainly of stacked plate pairs 12, 12′, 102 with manifold members 37 in the form of end bosses 38, 112 integrally formed in the plates, the present invention can also be incorporated into heat exchangers wherein the manifold members 37 are in the form of thin washers or tubular members, as will be described in detail below in connection with
Referring now to
When the plate pairs 201 are stacked together to form the heat exchanger 200, they are spaced-apart from each other by manifold members 37 in the form of tubular members 214. The tubular members 214 space-apart the plate pairs 201 thereby forming a second set of fluid channels 215 between the adjacent plate pairs 201, the second set of fluid channels 215 being transverse to the first set of fluid channels 212 formed by plate pairs 201. The tubular members 214 are positioned at opposed ends of the plates 202, 204. Each tubular member 214 has first and second open ends 216, 218 having flanged end edges 220, 222, respectively (see
As best seen in
As with the previously described embodiments, first and second plates 202, 204 are identical to each other with the second plate 204 being inverted and, in some embodiments, rotated 180 degrees with respect to the first plate 202. In the embodiment shown in
While the subject embodiment has been shown as having only one inlet/outlet opening 214 formed with a raised lip portion 226 and as employing tubular members 214 having a second end 218 adapted to cooperate with the raised lip portion 226, it will be understood that if both the inlet and outlet openings 224 are formed with raised lip portions 226, the tubular member 214 could be formed with identical first and second ends 216, 218, and the second plate 204 would simply be turned upside down with respect to the first plate 202 rather than having to also be rotated 180 degrees with respect thereto.
Referring again to
While the protrusion member 56 in the subject embodiment has been described as being in the form of a stepped-flange extension, it will be understood that any of protrusion members 56 described in connection with the previous embodiments may be incorporated into the subject design. More specifically, the protrusion member 56 may be in form of a half-dimple, a rib, a stepped-flange or flange extension, etc. and may have either flat or rounded mating surfaces.
Furthermore, it will be understood that cooling fins (not shown) could be located in the second set of flow channels 215 formed between the plate pairs 201. As with the previous embodiments, any type of cooling fin could be used, as desired. As well, the turbulizer 46 located in the first set of fluid channels 212 is shown as extending the entire length of the fluid channels 212, the turbulizer 46 could instead have a length corresponding to the distance provided between the openings 224 formed in the plates 202, 204 so as to prevent any pressure drop that may be associated with the first fluid entering the first set of fluid channels 212.
In a typical application, the components of heat exchanger 10, 100, 200 are made of brazing clad aluminum (except for the peripheral components such as fittings 28, 30). In general, the brazing clad aluminum that is typically used for heat exchanger plates have a metal thickness between in the range of about 0.012 inches (0.030 cm) and about 0.040 inches (0.102 cm). While it is desirable to use as thin a gauge material as possible since thinner gauge material tends to braze better and decreases the overall weight of the device, thinner gauge material has less mechanical strength than thicker materials, especially after brazing. Therefore, the use of thinner gauge material is limited by the specific strength requirements of the heat exchanger plates.
In heat exchanger 10, 100, 200 however, it has been found that the additional brazing surface provided by the protrusion members 56 increases the overall strength of the heat exchanger 10, 100, 200 so that thinner gauge material may be used to form the heat exchanger plates without compromising their inherent strength. More specifically, it has been found that plates manufactured out of thinner gauge material, such as 0.020 inches (0.051 cm), offer the equivalent or even better mechanical durability than plates that are made out of a thicker gauge material, i.e. 0.029 inches (0.074 cm). Accordingly, the heat exchanger 10, 100, 200 of the present invention can be made of thinner gauge material, thereby increasing the likelihood of achieving a good braze and reducing the overall weight of the heat exchanger 10, 100, 200 without compromising the overall strength and durability of the device. Plate thickness, therefore, tends to be in the range of about 0.012 inches (0.030 cm) to about 0.039 inches (0.099 cm), although plates having a thickness in the range of about 0.016 inches (0.041 cm) to about 0.020 inches (0.051 cm) are preferred.
In one application, heat exchanger 10, 100, 200 is used as an in-tank engine or transmission oil cooler. Typically, in-tank oil coolers are mounted inside the cold tank of the radiator of the vehicle. Engine or transmission oil flows through the closed circuit of fluid channels 36, 212 through the heat exchanger 10, 100, 200 as the first fluid, while the water or coolant, which flows through the radiator, flows around and through the second set of flow channels 39, 215 formed between the plate pairs 12, 12′, 60, 61, 102, 201 as the second fluid through heat exchanger 10, 100, 200. A difficulty that is sometimes encountered with in-tank oil coolers is that the liquid flowing around the heat exchanger 10, 100, 200 does not always flow through the flow channels 39, 215 between the plate pairs (i.e. through the core of the heat exchanger 10) but tends to by-pass the core and flow around the end portions 48, 118 of the heat exchanger 10, 100, 200 thereby decreasing the overall performance of the heat exchanger 10, 100, 200. The inclusion of the protrusion members 56 in the periphery of the plate pairs 12, 12′, 60, 61, 102, 201, however, tends to decrease this type of by-pass flow by helping to block the flow of fluid around the periphery of the plate pairs 12, 12′, 60, 61, 102, 201 and encouraging the fluid to through the flow channels 39, 215 between the individual plate pairs 12, 12′, 60, 61, 102, 201.
Having described the preferred embodiments of the invention, it will be appreciated that various modifications may be made to the structures described without departing from the spirit or scope of the invention described herein. For instance, while the plates 18, 19, 67, 68, 104, 106, 202, 204 have been shown as having flat central planar portions 34, 108, 208 with a fin or turbulizer 46 located therebetween, the central planar portions may instead be formed with inwardly disposed surface protrusions (not shown), such as dimples or ribs for example, which are spaced uniformly over the surface thereof. The inwardly disposed surface protrusions not only provide additional support to the central planar portions 34 which helps to prevent the central planar portions from sagging when the plates are heated to brazing temperatures, the inwardly disposed surface protrusions also create turbulence in the fluid flowing through the fluid channels formed inside the plate pairs 12.
As well, rather than having inwardly disposed surface protrusions formed in the central planar portions 34, 108, 208 of the plates, the plates may instead be formed with outwardly disposed surface protrusions 130 (in the form of dimples or ribs for example) which are spaced uniformly over the surface thereof, as shown in
Furthermore, while the heat exchanger 10, 100, 200 has been described as being made of aluminum, heat exchanger 10, 100, 200 can be made from other materials such as stainless steel, brass, or even a non-metallic material. In the case of stainless steel, a brazing cladding layer or copper could be used to ensure a proper seal is created between the stacked plates. As well, the length of the heat exchanger plates can be made to any length suitable for a desired application, and any number of plate pairs 12, 60, 61, 102, 201 may be used to create a heat exchanger 10, 100, 200 of the desired dimensions.
This application is a continuation of U.S. application Ser. No. 11/941,353 filed Nov. 16, 2007 entitled HEAT EXCHANGER WITH MANIFOLD STRENGTHENING PROTRUSION.
Number | Name | Date | Kind |
---|---|---|---|
4987955 | Bergqvist et al. | Jan 1991 | A |
5036911 | So et al. | Aug 1991 | A |
5184673 | Hedman et al. | Feb 1993 | A |
5369883 | So et al. | Dec 1994 | A |
5538077 | So et al. | Jul 1996 | A |
5634518 | Burgers | Jun 1997 | A |
5638900 | Lowenstein et al. | Jun 1997 | A |
5794691 | Evans et al. | Aug 1998 | A |
6170567 | Nakada et al. | Jan 2001 | B1 |
6478080 | Pinto | Nov 2002 | B2 |
6497274 | Cheadle | Dec 2002 | B2 |
6837305 | Zurawel et al. | Jan 2005 | B2 |
6889758 | Burgers et al. | May 2005 | B2 |
20020050347 | Hanley et al. | May 2002 | A1 |
20050082049 | Brost | Apr 2005 | A1 |
20060032621 | Martin et al. | Feb 2006 | A1 |
20060048917 | Persson | Mar 2006 | A1 |
Number | Date | Country |
---|---|---|
859837 | Jan 1961 | GB |
2000018872 | Jan 2000 | JP |
2006083446 | Aug 2006 | WO |
Number | Date | Country | |
---|---|---|---|
20120061062 A1 | Mar 2012 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 11941353 | Nov 2007 | US |
Child | 13300724 | US |