HEAT EXCHANGER ASSEMBLY AND METHOD

Abstract

A heat exchanger assembly and method of servicing is described and illustrated, and in some embodiments includes a pair of core units in an end-to-end arrangement, and a fluid tank arranged between the core units. Each core unit includes air fins arranged in parallel with one another and spaced apart in a core stacking direction, and parallel arranged fluid conveying tubes located between and bonded to adjacent air fins. The fluid tank includes a first end sealingly attached to a header plate of one core unit and a second end sealingly attached to a header plate of the other core unit. The fluid tank can be crimped to adjacent core units, and can be located entirely within the core stacking direction outermost boundaries of at least one of the core units.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application No. 61/415,588, filed Nov. 19, 2010, the entire contents of which are incorporated by reference herein.

BACKGROUND

Heat exchangers of various kinds are commonly used to transfer thermal energy from a first, hotter fluid to a second, cooler fluid. As one example well-known in the art, an internal combustion engine in an automobile or truck is kept operating at a desirable temperature with the use of a liquid coolant loop that removes waste heat from the engine and transfers it to a lower temperature air stream in a heat exchanger (i.e. a radiator). Such radiators typically include a plurality of fluid conduits to convey the coolant through the radiator, with ambient air directed over the outer surfaces of the tubes to convectively transfer heat away from the outer surfaces of the fluid conduits.

It should be readily apparent that the rate of heat transfer required in the radiator in order to maintain such a desirable engine temperature (sometimes referred to as the thermal load) increases proportionally with the power output of the engine. Consequently, large power-intensive machinery (such as, for example, agricultural, construction and mining equipment) require large radiators in order to provide adequate heat rejection surface area for these thermal loads. Producing radiators of such a large size can be problematic.

Compact and highly efficient radiators for automobiles and trucks are often produced in a cost-effective manner by metallurgical joining of at least certain portions of the radiator in a furnace brazing operation. However, as the size of the radiator is increased the physical limitations of the furnace can be reached, and alternate construction methods that are less cost-effective and/or result in less compact and less efficient heat exchangers may be employed out of necessity. As an example, in some large equipment the radiator is constructed using a large number of individual finned heat exchange tubes inserted through grommet seals.

SUMMARY

According to some embodiments of the invention, a heat exchanger assembly includes a pair of core units in an end-to-end arrangement and a fluid tank arranged between the core units. Each core unit includes a plurality of air fins arranged in parallel with one another and spaced apart from one another in a core stacking direction. Each core unit additionally includes a plurality of parallel arranged fluid conveying tubes located between and bonded to adjacent ones of the plurality of air fins. First and second spaced apart header plates sealingly receive the first and second ends, respectively, of the tubes. First and second side plates are located adjacent outermost ones of the air fins to define an outermost boundary of the core unit in the core stacking direction. The fluid tank includes a first end and a second end opposite the first end, the first end being sealingly attached to one of the first and second header plates of one of the pair of core units and the second end being sealingly attached to one of the first and second header plates of the other of the pair of core units. The fluid tank is located entirely within the outermost boundary of at least one of the pair of core units in the core stacking direction.

In some embodiments the fluid tank is sealingly attached to at least one of the pair of core units by a crimp joint. In some embodiments a gasket is included between the fluid tank and a header plate of at least one of the core units.

A heat exchanger assembly according to some embodiments of the invention additionally includes at least one of an inlet tank and an outlet tank sealingly attached to the other of the first and second header plates of the one of the pair of core units.

In some embodiments the heat exchanger assembly includes a second pair of core units adjacent to the first pair in the core stacking direction of at least one core unit. Some such embodiments include a structural frame supporting the first and second pair of core units. In some embodiments the center tank and the fluid conveying tubes of the first pair of core units together define a first fluid flow path and the center tank and the fluid conveying tubes of the second pair of core units together define a second fluid flow path. The first and second fluid flow paths are arranged in parallel with one another with respect to a fluid passing therethrough.

According to some embodiments of the invention, a heat exchanger includes first and second core units. Each core unit has a set of substantially parallel tubes extending in a direction through the core unit. Each of the tubes has first and second ends opposite one another. A header is coupled to the first ends of the set of substantially parallel tubes to form a fluid-tight seal. A tank is located between the first and second core units and has opposite ends. A header of each of the first and second core units is crimped in fluid-tight engagement with a respective one of the opposite ends. The tank has at least one interior space in fluid communication with interior spaces of the substantially parallel tubes of the first and second core units.

According to another embodiment of the invention, a method of servicing a heat exchanger includes disconnecting a first pair of core units from a second pair of core units, the first and second pairs of core units being supported by a common frame. The method can include terminating fluid communication between tubes of the first pair of core units and tubes of the second pair of core units by disconnecting the first pair of core units from the second pair of core units. The method can further include removing the first pair of core units from the frame while keeping the second pair of core units in place in the frame.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a heat exchanger assembly according to an embodiment of the present invention.

FIG. 2 is a partial perspective view of select portions of the heat exchanger assembly of FIG. 1.

FIG. 3 is a partial perspective detail view of the portion III-III of FIG. 1.

FIG. 4 is a partial sectional view along the lines IV-IV of FIG. 3.

FIG. 5 is a perspective view of a tank for use in the heat exchanger assembly of FIG. 1.

FIG. 6 is a perspective view of a heat exchanger assembly according to another embodiment of the present invention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

A heat exchanger assembly 1 according to an embodiment of the present invention is shown in FIG. 1, and includes first and second core units 2 in an end-to-end arrangement. Although the exemplary embodiment of FIG. 1 shows two such core units, it should be understood that a heat exchanger assembly 1 might also include additional such core units. Additional core units 2 may similarly be arranged in end-to-end fashion with one another, or they may be arranged in end-to-end fashion with one of the first and second heat exchange core units 2 shown in FIG. 1, or both.

Each core unit 2 comprises a tube and fin matrix 3 (shown in greater detail in FIG. 2), first and second header plates 5, and first and second side plates 6. The tube and fin matrix 3 includes a plurality of air fins 10 and a plurality of fluid conveying tubes 11. The air fins 10 are arranged in parallel with one another, and are spaced apart from one another in a core stacking direction (indicated by the double-ended arrow A) so that the tubes 11 can be located between adjacent ones of the air fins 10 to create an interleaved matrix of tubes and air fins. The air fins 10 and tubes 11 can be bonded with one another at their contacting locations in order to effect a low resistance to the transfer of heat between a fluid passing through the tubes 11 and a flow of air passing over the surfaces of the air fins 10 during operation of the heat exchanger assembly 1. Such bonding may be accomplished by brazing, welding, soldering, gluing, or other methods known in the art of heat exchangers.

The air fins 10 or tubes 11 or both can be constructed from metallic materials, including but not limited to aluminum, copper, steel, and the like. Alternatively, the air fins 10 or tubes 11 or both can be constructed from nonmetallic materials such as, for example, plastic. Although not shown in the exemplary embodiment, in some embodiments the fluid conveying tubes 11 can include internal webbing, inserts, or other features to increase turbulence and thereby enhance heat transfer in order to satisfy specific requirements of the application for which the heat exchanger assembly 1 is intended.

The air fins 10 depicted in FIG. 2 are of a serpentine type, but it should be understood that alternate air fin types known in the art can be similarly employed. For example, in some embodiments the air fins 10 can have a square-wave shape. In still other embodiments, the air fins 10 can be plate fins. The air fins can include turbulating features, including but not limited to louvers, bumps, slits, lances, offsets, and combinations of the same.

The first and second header plates 5 of each heat exchange core 2 are spaced apart from one another in the tube-axial direction of the tubes 11 of said core unit 2. Each of the header plates 5 includes a plurality of tube slots 12 (FIG. 4) arranged along the stacking direction A in one-to-one correspondence with the plurality of tubes 11. A first end of each of the tubes 11 extends into, and is sealingly received by, a corresponding one of the tube slots 12 in a first header plate 5, and a second end of each of the tubes 11 extends into, and is sealingly received by, a corresponding one of the tube slots 12 in a second header plate 5. Sealing between the header plates 5 and the ends of the tubes 11 can be accomplished by brazing, welding, gluing, or other joining and sealing methods known in the art of heat exchangers. The header plates 5 can, in some embodiments, be stamped metallic parts. In other embodiments, the header plates 5 can be injection molded plastic parts. In still other embodiments, the header plates 5 can be constructed of other materials, or can be made by other methods, or both.

The first and second side pieces 6 of each core unit 2 are arranged adjacent outermost ones of the air fins 10 of the core unit 2 in order to bound the tube and fin matrix 3 in the core stacking direction A. In other words, the first and second side pieces 6 of a core unit 2 can define the outermost boundaries of the core unit 2 in the core stacking direction A. The side pieces 6 can be used during the joining of the tube and fin matrix 3 to apply a compressive load in the core stacking direction A in order to ensure that contact between adjacent ones of the air fins 10 and tubes 11 is maintained. In some embodiments, it can be advantageous for the side plates 6 to be joined to the outermost air fins 10. By way of example only, in some embodiments the air fins 10, fluid conveying tubes 11, header plates 5 and side pieces 6 can all be constructed of aluminum or an aluminum alloy, and can be joined together in one or more brazing operations to form a core unit 2.

The embodiment of FIG. 1 further includes first and second fluid tanks 7 connected to header plates 5 at opposite ends of the heat exchanger assembly 1. These tanks 7 can serve as inlet and outlet tanks for a fluid passing through the fluid conveying tubes 11 of the heat exchanger assembly 1. During operation of the heat exchanger assembly 1, a fluid can be received by one of the tanks 7 through a port 8 located on that tank 7, and can be distributed to the fluid conveying tubes 11 of the core unit 2 that includes the header plate 5 to which that tank 7 is connected. After passing through the tubes 11 of at least two of the core units 2, the fluid can be received into another one of the tanks 7, and can be removed from the heat exchanger assembly 1 through the port 8 located on that other tank 7.

In order to prevent undesirable leakage of fluid from the heat exchanger assembly during operation, a fluid-tight seal can be provided between the tanks 7 and the corresponding header plates 5. In the exemplary embodiment of FIG. 3 and FIG. 4, such a seal is provided by the use of a gasket 13 that extends along the entire outer perimeter of a corresponding header plate 5, and is compressed between that header plate 5 and the corresponding tank 7. The compressive load is maintained by tabs 14 arranged along the outer periphery of the header plate 5 and deformed to engage against a flange 16 along the outer periphery of the tank 7. During assembly of the tank 7 to the header plate 5, a load can be applied to the tank and header plate in order to compress the gasket 13, and the tabs 14 can be deformed to maintain the compressive load. FIG. 3 shows a plurality of such tabs 14 along the periphery of a header plate 5 prior to being so deformed, while FIG. 4 shows one of the tabs 14 in a subsequent, deformed condition. A joint of this nature is often referred to in the art as a crimp joint. Such a joint may be especially desirable when the tank 7 is constructed of a material that does not lend itself to traditional metallurgical joining methods such as welding, soldering or brazing (for example, when the tank 7 is constructed of plastic). Also, other joining methods may not be suitable for many applications. By way of example only, in many cases the use of bolts, screws, or other threaded fasteners is impractical, including but not limited to when access to the fasteners is not possible, when localized fastening points are not suitable for a sufficient or reliable compressive connection between parts, when space and packaging constraints eliminate the possibility of using fasteners and fastener holes, and/or when the use of compressed and crimped joints enables lower heat exchanger production and assembly costs.

The heat exchanger assembly 1 further includes an intermediate fluid tank 4 located between the first and second core units 2. One embodiment of such an intermediate tank 4 is shown in greater detail in FIG. 5. The intermediate tank 4 has a first open face 15 located at a first end of the tank 4, and a second open face 15 located at a second end of the tank 4 opposite the first end. During operation, a fluid is allowed to flow into the intermediate tank 4 through the first open face 15 from a core unit 2 located upstream (with respect to the fluid flow) of the intermediate tank 4, and to allow the fluid to flow out of the intermediate tank 4 through the second open face 15 into a core unit 2 located downstream (with respect to the fluid flow) of the intermediate tank 4.

Ribs 17 can be included within the intermediate tank 4. These ribs 17 can be used to strengthen the intermediate tank 4 with respect to loads exerted by fluid pressure acting on the tank walls, and can also provide structural support for the heat exchanger assembly 1 (e.g., against forces tending to rotate or tilt one core unit 2 with respect to another). Additionally or alternatively, the ribs 17 can be used to prevent at least some re-mixing of the fluid within the intermediate tank 4. The ribs 17 shown in FIG. 5 are arranged so that one rib 17 is located between each pair of adjacent tubes 11. In other embodiments of the invention, fewer ribs 17 are used, and in some embodiments the ribs 17 are eliminated entirely.

The exemplary intermediate tank 4 of the illustrated embodiment includes first and second flanges 16 extending around each of the two open faces 15, similar to the flange 16 of the tank 7 in FIG. 4. At least one of the flanges 16 of the intermediate tank 4 can be used, in conjunction with a gasket 13, to create a fluid-tight seal between said intermediate tank 4 and the header plate 5 arranged alongside the adjacent open face 15 by creating a crimp joint as was previously described with reference to FIG. 4. Again, such a joint can be especially desirable when the intermediate tank 4 is constructed of plastic, and also finds particular use in a variety of applications where other joining methods are not possible or are unsuitable.

In so joining the intermediate tank 4 to a core unit 2, the intermediate tank 4 can be advantageously located within the previously described core stacking direction outermost boundaries of the core unit 2. By having the intermediate tank 4 so located, multiple heat exchanger assemblies 1 can be placed immediately adjacent one another in the core stacking direction A. Also, the use of crimp joints between the intermediate tank 4 and the adjacent core units 2 (as described above) enables a maintenance-free compressed joint requiring no screws, bolts, or other separate fasteners, in one embodiment, while still providing a strong and stable connection between the core units 2.

In an alternative embodiment 101 of a heat exchanger assembly according to the present invention (shown in FIG. 6), a plurality of pairs of core units 2 are arranged immediately adjacent one another in the core stacking direction A. Each of said pairs of core units 2 includes an intermediate tank (such as the intermediate tank 4 of FIG. 5) joined to the core units 2 as previously described, as well as an inlet tank and an outlet tank (such as the tanks 7 shown in the embodiment of FIG. 1) joined to opposing ends of said pair. A structural frame 107 comprising first and second end channels 102 and first and second side channels 103 is used to secure the pairs of core units 2 within the heat exchanger assembly 102.

The illustrated structural frame 107 includes a center rail 104 spanning between the side channels 103 to strengthen the heat exchanger assembly 101. Also with reference to the illustrated embodiment by way of example, fasteners 106 are used to secure the center rail 104 to the side rails 103, as well as to secure the intermediate tanks to the center rail 104 and to secure the inlet tanks and the outlet tanks to the end channels 102. The fasteners 106 used in the exemplary embodiment of FIG. 6 are threaded bolts, but it should be understood that a variety of fasteners such as, for example, screws, rivets and the like, can be equally suitable. Mounting holes 9 in the intermediate tanks 4 and the inlet and outlet tanks (shown in detail FIG. 1 and FIG. 5) are used to receive the fasteners 106. In some embodiments, the fasteners 106 extend entirely through the mounting holes 9 and are secured at the opposing face of the heat exchanger assembly 1, whereas in other embodiments the fasteners 106 are secured directly to the mounting holes 9. The structural frame 107 can optionally include cross bars 105 to further strengthen the heat exchanger assembly 101.

By utilizing a heat exchanger assembly 1, 101 as described above (having at least two core units 2 joined in end-to-end fashion via one or more intermediate tanks 4 as also described above), the overall heat exchanger assembly 1, 101 can be modular in nature. In particular, a user in some embodiments can partially disassemble the system to remove, service, repair, and/or replace one or more of the pairs of core units 2 and intermediate tank 4 as desired. In some embodiments, this action can be performed without disassembly or removal of the other core units 2 in the system.

With continued reference to the heat exchanger assembly 101 of FIG. 6, the fluid or center tank and the fluid conveying tubes of a first pair of core units 2 can together at least partially define a first fluid flow path, and the center tank and fluid conveying tubes of a second pair of core units 2 can together at least partially define a second fluid flow path. Similarly, the center tank and fluid conveying tubes of a third pair of core units 2 can together at least partially define a third fluid flow path. The inlet tanks of at least two of the pairs of core units 2 can be plumbed together so that their respective fluid flow paths are in parallel with one another. In some embodiments, at least one of the fluid flow paths is in series with at least one other of the fluid flow paths.

A heat exchanger assembly as described above can find utility as an engine coolant radiator for use in large machinery, such as construction, agricultural, and mining equipment, among others. In some embodiments, such a radiator is used to reject heat from a flow of coolant passing through the tubes of the core units to an air flow directed over the air fins and the outer surfaces of the tubes. It should be understood, however, that a heat exchanger assembly according to the present invention can find utility in other applications as well.

Several advantages can be realized through the use of a heat exchanger assembly as described. As one example, a highly effective brazed tube and fin core construction can be used to create a heat exchanger assembly that is larger in face area than can be accommodated within an available brazing furnace. The heat exchanger assembly can thus be constructed of compact core units that are compactly packaged together with minimal air blockage or bypass. As another example, individual core sections of the heat exchanger assembly can be replaced when damaged without needing to replace the entire heat exchanger assembly, thus decreasing the repair and replacement cost.

Various alternatives to certain features and elements of the present invention are described herein with reference to specific embodiments of the present invention. With the exception of features, elements, and manners of operation that are mutually exclusive of or are inconsistent with each embodiment described above, it should be noted that the alternative features, elements, and manners of operation described with reference to one particular embodiment are applicable to the other embodiments.

The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention.

Various features and advantages of the invention are set forth in the following claims.

Claims

1. A heat exchanger assembly comprising:

a fluid tank; and

a pair of core units in an end-to-end arrangement, with the fluid tank positioned between and having an interior in fluid communication with the pair of core units, each of the core units including, a plurality of air fins parallel to and spaced apart from one another in a core stacking direction, a plurality of parallel fluid conveying tubes located between and coupled to adjacent ones of the plurality of air fins, first and second spaced apart header plates sealingly receiving first and second ends, respectively, of the plurality of parallel fluid conveying tubes, and first and second side plates located adjacent outermost ones of the plurality of air fins to define an outermost boundary of each core unit in the core stacking direction;

wherein the fluid tank includes a first end and a second end opposite the first end, the first end being sealingly attached to one of the first and second header plates of one of the pair of core units, and the second end being sealingly attached to one of the first and second header plates of the other of the pair of core units, the fluid tank being located entirely within the outermost boundary of at least one of the pair of core units in the core stacking direction.

2. The heat exchanger assembly of claim 1, wherein the fluid tank is sealingly attached to at least one of the pair of core units by a crimp joint.

3. The heat exchanger of claim 1, further comprising at least one of an inlet tank and an outlet tank sealingly attached to the other of the first and second header plates of the one of the pair of core units.

4. The heat exchanger of claim 3, further comprising the other of an inlet tank and an outlet tank sealingly attached to the other of the first and second header plates of the other of the pair of core units.

5. The heat exchanger of claim 1, further comprising a gasket positioned between the fluid tank and one of the first and second header plates of one of the pair of core units.

6. The heat exchanger of claim 1, wherein each core unit is a brazed aluminum core unit.

7. The heat exchanger of claim 1, wherein the fluid tank is made of plastic.

8. The heat exchanger assembly of claim 1, wherein the pair of core units is a first pair of core units, and further comprising a second pair of core units adjacent the first pair of core units in the core stacking direction.

9. The heat exchanger of claim 8, further comprising a structural frame supporting the first and second pair of core units.

10. The heat exchanger assembly of claim 8, wherein the fluid tank is a first fluid tank, the heat exchanger assembly further comprising a second fluid tank, wherein the first fluid tank and the plurality of parallel fluid conveying tubes of the first pair of core units together at least partially define a first fluid flow path, and wherein the second fluid tank and the plurality of parallel fluid conveying tubes of the second pair of core units together at least partially define a second fluid flow path.

11. The heat exchanger assembly of claim 10, wherein the first and second fluid flow paths are arranged in parallel with one another with respect to a fluid passing therethrough.

12. The heat exchanger assembly of claim 10, wherein the first and second fluid flow paths are arranged in series with one another with respect to a fluid passing therethrough.

13. A heat exchanger comprising:

first and second core units, each core unit having a set of substantially parallel tubes extending in a direction through the core unit, each tube having first and second ends opposite one another, and a header coupled to and forming a fluid-tight seal with the first ends of the set of substantially parallel tubes; and

a tank located between the first and second core units and having opposite ends, the header of each of the first and second core units crimped in fluid-tight engagement with a respective one of the opposite ends, the tank having at least one interior space in fluid communication with interior spaces of the plurality of substantially parallel tubes of the first and second core units.

14. The heat exchanger of claim 13, wherein the headers of the first and second core units are deformed to define crimped joints with the opposite ends of the tank.

15. The heat exchanger of claim 13, further comprising a gasket compressed between each opposite end of the tank and the corresponding header of the first and second core units.

16. The heat exchanger of claim 13, wherein the first and second core units are a first pair of core units, and further comprising a second pair of core units adjacent the first pair of core units, wherein the set of substantially parallel tubes of the first pair of core units extend in substantially the same direction as the set of substantially parallel tubes of the second pair of core units.

17. The heat exchanger of claim 16, further comprising a second tank extending across and coupling adjacent ends of the first core units in the first and second pairs of core units.

18. The heat exchanger of claim 17, wherein the second tank has an interior establishing fluid communication between the set of substantially parallel tubes of the first core units of the first and second pairs of core units.

19. The heat exchanger of claim 13, further comprising first and second side plates located adjacent outermost ones of the set of substantially parallel tubes of each of the first and second core units.

20. The heat exchanger of claim 19, wherein the tank and the first and second core units have respective widths extending transverse to the set of substantially parallel tubes of the first and second core units, and wherein a width of the tank is no greater than the widths of the first and second core units.

21. A method of servicing a heat exchanger, the method comprising:

disconnecting a first pair of core units from a second pair of core units, the first and second pairs of core units supported by a common frame, each of the first and second pair of core units including, a first core unit and a second core unit; a set of substantially parallel tubes extending in a direction through one of the first and second core units, each tube having a first end and a second end opposite one another; a header coupled to and forming a fluid-tight seal with the first ends of the set of substantially parallel tubes; and a tank located between the first core unit and the second core unit, the tank having opposite ends each secured in fluid-tight engagement with a corresponding header of the first and second core units, the tank having at least one interior space in fluid communication with interior spaces of the plurality of substantially parallel tubes;

terminating fluid communication between the set of substantially parallel tubes of the first pair of core units and the set of substantially parallel tubes of the second pair of core units by disconnecting the first pair of core units from the second pair of core units; and

removing the first pair of core units from the frame while keeping the second pair of core units in place in the frame.