US20080006390A1

US20080006390A1 - Thermal relief mechanism for combination-type heat exchangers

Info

Publication number: US20080006390A1
Application number: US11/483,785
Authority: US
Inventors: Ken Nakayama; David M. Scoville
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-07-10
Filing date: 2006-07-10
Publication date: 2008-01-10

Abstract

A multi-fluid heat exchanger (10) is provided for transferring heat between a common fluid and a first fluid in one core section (22), and between the common fluid and a second fluid in another core section (28) of the heat exchanger (10). The core sections (22,28) are located in a series arrangement with respect to the flow of the common fluid through the heat exchanger (10) by folding the heat exchanger (10), with the core sections (22,28) being connected by folded portions (20) of the header pipes (12,14) that direct the first and second fluid flows to the interiors of the core sections (22,28).

Description

FIELD OF THE INVENTION

This invention relates to heat exchangers and more particularly to combination-type heat exchangers wherein heat exchanger cores for two or more fluids share a common manifold or header, and in more particular applications, to such heat exchangers as used in vehicular systems, such as automobiles, buses, trucks, etc.

BACKGROUND OF THE INVENTION

It is known to form a so-called “combination” or “combo” type heat exchanger by including one or more baffles in each of the manifolds or headers of the heat exchanger to divide the interiors of each of the headers into at least a first section for a first working fluid and a second section for a second working fluid, with each of the working fluids being directed through the respective heat exchange tubes that are connected to the respective sections of the common manifolds. The resulting structure provides a “stacked” arrangement of heat exchanger cores. While such constructions may be suitable for their intended purposes, problems can arise when there are space limitations and one or both of the combined heat exchangers requires more capacity (i.e., more face area). Accordingly, there is a continued need for improvement in combo heat exchangers.

SUMMARY OF THE INVENTION

In accordance with one feature of the invention a multi-fluid heat exchanger is provided for transferring heat between a common fluid and a first fluid in one part of the heat exchanger and between the common fluid and a second fluid in another part of the heat exchanger. The heat exchanger includes a pair of spaced, elongated header pipes to direct the first and second fluids to and from the heat exchanger, each of the header pipes including a first fluid manifold for the first fluid and a second fluid manifold for the second fluid with the first and second fluid manifolds connected by a folded portion of the elongate header pipe. The heat exchanger further includes a first core section to transfer heat between the common fluid and the first fluid as the common and first fluids pass through the first core section, the first core section extending between the header pipes and connected at opposite sides to the first fluid manifold in each header to transfer the first fluid between the header pipes and the first core section, and a second core section to transfer heat between the common fluid and the second fluid as the common and second fluids pass through the second core section, the second core section extending between the header pipes and connected at opposite sides to the second fluid manifold in each header to transfer the second fluid between the header pipes and the second core section. The second core section is positioned downstream from the first core section with respect to a flow direction of the common fluid through the first and second core sections to receive the common fluid after it has passed through the first core section.
In one feature, the multi-fluid heat exchanger further includes a structural support on one of the header pipes and connected to both the first and second fluid manifolds at a location spaced from the folded portion.
According to one feature, the first and second manifolds of each header pipe are separated from each other by a cut located adjacent the folded portion.
As one feature, each of the header pipes is a cylindrical tube having a plurality of tube receiving openings spaced along a length of the header pipe to receive ends of heat exchange tubes from the first and second cores.
In one feature, each of the first and second cores includes a plurality of parallel, spaced, flattened tubes, each of the tubes having a first end and a second end, with the first end received in one of the header pipes and the second end received in the other header pipe to direct the corresponding one of the first and second fluids between the first and second header pipes through an interior of the tube. In a further feature, each of the first and second cores further includes corrugated fins extending between adjacent pairs of said tubes.
In accordance with one feature of the invention, a multi-fluid heat exchanger is provided for transferring heat between a first fluid and a common fluid in one part of the heat exchanger and between a second fluid and the common fluid in a second part of the heat exchanger. The heat exchanger includes a first core section, a second core section, and a first elongated header pipe having a plurality tube receiving openings spaced along a length of the first header pipe, a second elongate header pipe having a plurality of tube receiving openings spaced along a length of the second header pipe. The first core section includes a plurality of parallel, spaced tubes, each of the tubes having a first end and a second end, with the first end received in a corresponding one of the tube receiving openings of the first header pipe and the second end received in a corresponding one of the tube receiving openings of the second header pipe to direct the first fluid between the first and second header pipes through an interior of the tube. The second core section includes a plurality of parallel, spaced tubes, each of the tubes having a first end and a second end, with the first end received in a corresponding one of the tube receiving openings of the first header pipe and the second end received in a corresponding one of the tube receiving openings of the second header pipe to direct the second fluid between the first and second header pipes through an interior of the tube. Each of the header pipes has a folded portion at a location between the first and second cores to locate the second core downstream from the first core with respect to a flow path of the common fluid through the first and second cores.
As one feature, each of the header pipes includes a cut adjacent the folded portion between the first and second manifolds.
In one feature, each of the header pipes includes a cylindrical tube having the tube receiving holes formed therein.
According to one feature, the tubes of at least one of the cores are flattened tubes and the at least one of the cores further comprises corrugated fins extending between each adjacent pair of flattened tubes.
As one feature, the multi-fluid heat exchanger further includes a structural support on one of the header pipes and connected to both the first and second fluid manifolds at a location spaced from the folded portion.
In one feature, the multi-fluid heat exchanger further includes a third core section to transfer heat between the common fluid and a third fluid as the common and third fluids pass through the third core section. The third core section extends between the header pipes and is connected at opposite sides to a third fluid manifold in each header to transfer the third fluid between the header pipes and the third core section. The third fluid manifold is connected to one of the first and second fluid manifolds by another folded portion of the elongate header pipe. The third core section is positioned relative to at least one of the first and second core sections so that the common fluid passes through the third core section and the at least one of the first and second core sections in series fashion.
In accordance with one feature of the invention, a method is provided for making a multi-fluid heat exchanger for transferring heat between a first fluid and a common fluid in one part of the heat exchanger and between a second fluid and the common fluid in a second part of the heat exchanger. The method includes the steps of:
a) providing a heat exchanger with first and second core sections extending between a pair of elongated header pipes, with each of the header pipes having a first fluid manifold for the first core section and a second fluid manifold for the second core section;
b) providing a cut portion in each of the header pipes at a location between the first and second fluid manifolds, the cut portion leaving at least part of the header pipe connecting the first and second fluid manifolds of the header; and
c) folding the heat exchanger at the cut portion so that the at least part of the header pipe is deformed and the first and second core portions are located in series with respect to a flow path for the common fluid through the first and second core portions.
In one feature, the method further includes the step of connecting the first and second manifolds of at least one of the header pipes to each other at a location spaced from the cut portion after step c).
According to one feature, the method further includes the step of brazing the first and second core sections and the pair of elongated header pipes as an assembly prior to step c).
As one feature, the method further includes the step of brazing the first and second core sections and the pair of elongated header pipes as an assembly prior to step b).
In one feature, the method further includes the steps of:
d) providing the heat exchanger with a third core section extending between the pair of elongate header pipes, with each of the header pipes having a third fluid manifold for the third core section;
e) providing an additional cut portion in each of the header pipes at a location between the third fluid manifold and one of the first and second fluid manifolds, the additional cut portion leaving at least part of the header pipe connecting the third fluid manifold and the one of the first and second fluid manifolds of the header; and
f) folding the heat exchanger at the additional cut portion so that the at least part of the header pipe connecting the third fluid manifold and the one of the first and second fluid manifolds is deformed and the third core section is located in series with at least one of the first and second core sections with respect to a flow path for the common fluid through the third core section and the at least one of the first and second core sections.
In accordance with one feature of the invention, a method is provided for making a pair of heat exchangers for transferring heat between a first fluid and a common fluid in one of the heat exchangers and between a second fluid and the common fluid in the other of the heat exchangers. The method includes the steps of:
a) providing a heat exchanger with first and second core sections extending between a pair of elongated header pipes, with each of the pipes having a first fluid manifold for the first core section and a second fluid manifold for the second core section; and
b) completely severing each of the header pipes at a location between the first and second fluid manifolds to form the pair of heat exchangers, with one heat exchanger including the first fluid manifolds and the first core section, and the other heat exchanger including the second fluid manifolds and the second core section.
In one feature, the method further includes the step of securing the pair of heat exchangers to each other so that the first and second core portions are located in series with respect to a flow path for the common fluid through the pair of heat exchangers after step b).
Other advantages, features, and objects of the invention will be realized by a detailed review of the entire specification, including the appended claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are somewhat diagrammatic front elevations of a multi-fluid heat exchanger embodying the present invention, with FIG. 1A showing the heat exchanger before it is has been folded, and FIG. 1B showing the heat exchanger in its final, folded form;

FIGS. 2A and 2B are enlarged diagrammatic representations taken from line 2-2 in FIGS. 1A and 1B;

FIG. 3 is a view taken from line 3-3 in FIG. 1A showing more details of one preferred form of the heat exchanger of FIGS. 1A-2B;

FIG. 4 is a view similar to FIG. 2B but illustrating another embodiment of the invention; and

FIGS. 5 and 6 are views similar to FIG. 2A showing alternate embodiments of a multi-fluid heat exchanger embodying the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIGS. 1A-2B, a multi-fluid heat exchanger 10 is shown for transferring heat between a common fluid (shown schematically by arrows A in FIG. 2B) and a first fluid (shown schematically by arrows B in FIGS. 1A and 1B) in one part of the heat exchanger and between the common fluid and a second fluid (shown schematically by arrows C in FIGS. 1A and 1B) in another part of the heat exchanger 10. The heat exchanger 10 includes a pair of spaced, elongated header pipes 12 and 14 to direct the first and second fluids to and from the heat exchanger. Each of the header pipes 12,14 includes a first fluid manifold 16 for the first fluid and a second fluid manifold 18 for the second fluid, with the first and second fluid manifolds 16 and 18 being connected by a folded portion 20 of the elongate header pipe, best seen in FIG. 2B. The heat exchanger 10 further includes a first core section 22 to transfer heat between the common fluid and the first fluid as the common and first fluids pass through the first core section 22. The first core section 22 extends between the header pipes 12,14 and is connected at opposite sides 24 and 26 to the first fluid manifold 16 in each header pipe 12,14 to transfer the first fluid between the header pipes 12,14 and the first core section 22. The heat exchanger also includes a second core section 28 to transfer heat between the common fluid and the second fluid as the common and second fluids pass through the second core section 28. The second core section 28 extends between the header pipes 12,14 and is connected at the opposite sides 24 and 26 to the second fluid manifold 18 in each header pipe 12,14 to transfer the second fluid between the header pipes 12 and 14 and the second core section 28. As best seen in FIG. 2B, the second core section 28 is positioned downstream from the first core section 22 with respect to the flow direction A of the common fluid through the first and second core sections 22 and 28 to receive the common fluid after it has passed through the first core section 22.
While the common fluid, first fluid, and second fluid can be any fluids that require the exchange of heat in a system, in one preferred embodiment for automotive or truck-type applications, the common fluid is air and one of the first and second fluids is refrigerant with one of the core sections 22,28 being a condenser, and the other of the first and second fluids is oil, such as transmission oil, and the other core section 22,28 being an oil cooler.
As best seen in FIG. 3, each of the first and second cores 22 and 28 includes a plurality of parallel, spaced, flattened tubes 30 and 32, respectively, with each of the tubes 30 and 32 having one end received in one of the header pipes 12,14 and an opposite end received in the other header pipe 12,14 to direct the corresponding one of the first and second fluids between the first and second header pipes 12 and 14 through an interior of the tube 30,32. Each of the first and second cores 22 and 28 further includes corrugated or serpentine fins 34 and 36, respectively, extending between adjacent pairs of said tubes 30 and the tubes 32, respectively, to act as surface enhancements for the flow of the common fluid over the exterior of the tubes 30,32 and the fins 34 and 36. As also seen in FIG. 3 each of the header pipes 12,14 is preferably provided in the form of a cylindrical tube that has pierced tube slots or openings 40 to receive the ends of the tubes 30 and 32, with the end being sealingly bonded in the openings 40 using any suitable technique, such as by brazing. Each of the header pipes 12,14 further includes a pair of end baffles 42 and 44 to close the open ends of the headers pipe 12, 14 adjacent the folded portion 20. Preferably, the baffles 42 and 44 are inserted through cut baffle slots 46 and 48, respectively, and bonded in place, preferably during a common brazing operation that brazes all of the tubes 30 and 32, fins 34 and 36, and header pipes 12 and 14 together.
As best seen in FIGS. 2A, 2B, and 3, a cut 50 (typically made by a saw or grinder) is preferably created in each of the header pipes 12,14 between the first and second manifolds 16 and 18. The cut 50 only partially severs the header pipe 12,14, thereby leaving the folded portion 20, which is a tab 51 of the common material that forms the header pipe 12,14 which is left after the cut 50 has been formed. The cut 50 is preferably created after the remainder of the heat exchanger 10 has been assembled and brazed together, but may be created at any point during manufacture and assembly, including prior to assembly of all of the components of the heat exchanger 10 and/or prior to the brazing operation.
While a preferred embodiment of the heat exchanger 10 has been described above in some detail, it should be appreciated that there are many suitable forms for the various components of the heat exchanger 10. For example, while flattened tubes 30,32 have been shown, circular tubes or tubes of another cross sectional shape may prove desirable in some applications. By way of further example, while serpentine fins 34,36 have been shown, other fins, such as plate fins may be desirable in some applications. As yet a further example, while the header pipes 12 and 14 have been shown in the form of generally cylindrical tubes, with the baffles 42 and 44 inserted through baffle slots 46 and 48, other known header constructions and/or baffle constructions may be used, such as for example two piece header pipe designs utilizing a header plate and tank, and/or baffles that are inserted either through open ends of the header pipes or between header and tank pieces of a header pipe. As one last example, while each of the heat exchanger cores 22 and 28 have been shown as single pass cores, it may be desirable to provide multi-passing in one or both of the cores 22 and 28, such as by using baffles in one or both of the header pipes 12 and 14 to direct the corresponding fluid flow in multiple passes through the tubes, or by using serpentine tubes.
During assembly of the heat exchanger 10, the cores 22 and 28 are preferably first assembled together in a fixture with the tubes 30 and fins 34 interleaved and the tubes 32 and fins 36 interleaved, and a spacer in the form of a blank bar or tube 52 positioned at the interface between the cores 22 and 28 with no braze or braze coating so that the spacer 52 does not bond or braze to the adjacent fins 34 and 36. The cores are then compressed between sideplates 54 and 56, as is known, and the header pipes 12 and 14 are assembled to the cores with the ends of the tubes 30,32 received in the openings 40. The spacer 52 allows for the cores 22 and 28 to be compressed together. The assembled heat exchanger 10 is then brazed using a suitable braze operation. If the cuts 50 have not yet been made in the header pipes 12 and 14, the cuts 50 are next made using a suitable machining technique, such as by sawing or by grinding, and the heat exchanger is folded at the location of the cuts 50 so that the cores 22 and 28 are positioned in a series relationship with respect to the flow direction A of the common flow through the cores 22,28, with one of the cores 22 and 28 being positioned downstream from the other core 22,28 with respect to the common flow and connected by the folded portions 20 of the header pipes 12 and 14, as seen in FIGS. 1B and 2B. It should be noted that during or before folding, the spacer 52 can be removed because it should not have bonded or brazed to the adjacent fins 34 and 36. After the folding operation, a structural support 60, such as a clip in bracket 62, seen in FIG. 2B, is preferably attached to one of the header pipes 12 and 14 connected to both the first and second manifolds 16 and 18 at a location spaced from the folded portion 20. If desired, another structural support 60 can be provided on the other header pipes 12,14.
FIG. 4 shows an alternative embodiment of the heat exchanger 10 wherein the cuts 50 completely severe each of the headers pipes 12 and 14 so that the cores 22 and 28 are completely separated. The cores 22 and 28 are than connected in the series relationship described above using any suitable structural bracket or frame.
FIGS. 5 and 6 show yet further alternate embodiments of the heat exchanger 10 wherein there is an additional core section 70, additional fluid manifold 72, and an additional set of cuts 50 and folded portions 20, with the embodiment of FIG. 5 having the core section 70 placed in series relationship with the core section 22, and FIG. 6 showing the core section 70 being in series relationship with both the core sections 22 and 28, with respect to the direction of the common flow A through the heat exchanger 10.
It should be appreciated that the heat exchanger 10 enjoys the process cost savings associated with assembling and brazing a combination-type, multi-fluid heat exchanger utilizing common header pipes 12,14, while accommodating the available space requirements for a particular application by allowing the core sections 22 and 28 to be placed in a series relationship with respect to the direction of the common flow A through the heat exchanger 10.

Claims

1. A multi-fluid heat exchanger for transferring heat between a common fluid and a first fluid in one part of the heat exchanger and between the common fluid and a second fluid in another part of the heat exchanger, the heat exchanger comprising:

a pair of spaced, elongated header pipes to direct the first and second fluids to and from the heat exchanger, each of the header pipes including a first fluid manifold for the first fluid and a second fluid manifold for the second fluid with the first and second fluid manifolds connected by a folded portion of the elongate header pipe;

a first core section to transfer heat between the common fluid and the first fluid as the common and first fluids pass through the first core section, the first core section extending between the header pipes and connected at opposite sides to the first fluid manifold in each header to transfer the first fluid between the header pipes and the first core section; and

a second core section to transfer heat between the common fluid and the second fluid as the common and second fluids pass through the second core section, the second core section extending between the header pipes and connected at opposite sides to the second fluid manifold in each header to transfer the second fluid between the header pipes and the second core section, the second core section positioned downstream from the first core section with respect to a flow direction of the common fluid through the first and second core sections to receive the common fluid after it has passed through the first core section.

2. The multi-fluid heat exchanger of claim 1 further comprising a structural support on one of said header pipes and connected to both the first and second fluid manifolds at a location spaced from said folded portion.

3. The multi-fluid heat exchanger of claim 1 wherein the first and second manifolds of each header pipe are separated from each other by a cut portion located adjacent the folded portion.

4. The multi-fluid heat exchanger of claim 1 wherein each of the header pipes comprises a cylindrical tube having a plurality of tube receiving openings spaced along a length of the header pipe to receive ends of heat exchange tubes from the first and second cores.

5. The multi-fluid heat exchanger of claim 4 wherein each of the first and second cores comprises a plurality of parallel, spaced, flattened tubes, each of the tubes having a first end and a second end, with the first end received in one of the header pipes and the second end received in the other header pipe to direct the corresponding one of the first and second fluids between the first and second header pipes through an interior of the tube.

6. The multi-fluid heat exchanger of claim 5 wherein each of the first and second cores further comprises corrugated fins extending between adjacent pairs of said tubes.

7. The multi-fluid heat exchanger of claim 1 further comprising a third core section to transfer heat between the common fluid and a third fluid as the common and third fluids pass through the third core section, the third core section extending between the header pipes and connected at opposite sides to a third fluid manifold in each header to transfer the third fluid between the header pipes and the third core section, the third fluid manifold connected to one of the first and second fluid manifolds by another folded portion of the elongate header pipe, the third core section positioned relative to at least one of the first and second core sections so that the common fluid passes through the third core section and the at least one of the first and second core sections in series fashion.

8. A multi-fluid heat exchanger for transferring heat between a first fluid and a common fluid in one part of the heat exchanger and between a second fluid and the common fluid in a second part of the heat exchanger, the heat exchanger comprising:

a first elongated header pipe having a plurality tube receiving openings spaced along a length of the first header pipe;

a second elongate header pipe having a plurality of tube receiving openings spaced along a length of the second header pipe;

a first core section comprising a plurality of parallel, spaced tubes, each of the tubes having a first end and a second end, with the first end received in a corresponding one of the tube receiving openings of the first header pipe and the second end received in a corresponding one of the tube receiving openings of the second header pipe to direct the first fluid between the first and second header pipes through an interior of the tube;

a second core section comprising a plurality of parallel, spaced tubes, each of the tubes having a first end and a second end, with the first end received in a corresponding one of the tube receiving openings of the first header pipe and the second end received in a corresponding one of the tube receiving openings of the second header pipe to direct the second fluid between the first and second header pipes through an interior of the tube; and

each of the header pipes having a folded portion at a location between the first and second cores to locate the second core downstream from the first core with respect to a flow path of the common fluid through the first and second cores.

9. The multi-fluid heat exchanger of claim 8 wherein each of the header pipes comprises a cut adjacent the folded portion between the first and second manifolds.

10. The multi-fluid heat exchanger of claim 8 wherein each of the header pipes comprises a cylindrical tube having the tube receiving holes formed therein.

11. The multi-fluid heat exchanger of claim 8 further comprising a structural support on one of said header pipes and connected to both the first and second fluid manifolds at a location spaced from said folded portion.

12. The multi-fluid heat exchanger of claim 8 wherein the tubes of at least one of the cores are flattened tubes and the at least one of the cores further comprises corrugated fins extending between each adjacent pair of flattened tubes.

13. The multi-fluid heat exchanger of claim 7 further comprising a third core section to transfer heat between the common fluid and a third fluid as the common and third fluids pass through the third core section, the third core section extending between the header pipes and connected at opposite sides to a third fluid manifold in each header to transfer the third fluid between the header pipes and the third core section, the third fluid manifold connected to one of the first and second fluid manifolds by another folded portion of the elongate header pipe, the third core section positioned relative to at least one of the first and second core sections so that the common fluid passes through the third core section and the at least one of the first and second core sections.

14. A method of making a multi-fluid heat exchanger for transferring heat between a first fluid and a common fluid in one part of the heat exchanger and between a second fluid and the common fluid in a second part of the heat exchanger, the method comprising the steps of:

a) providing a heat exchanger with first and second core sections extending between a pair of elongated header pipes, with each of the header pipes having a first fluid manifold for the first core section and a second fluid manifold for the second core section;

b) providing a cut portion in each of the header pipes at a location between the first and second fluid manifolds, the cut portion leaving at least part of the header pipe connecting the first and second fluid manifolds of the header; and

c) folding the heat exchanger at the cut portion so that the at least part of the header pipe is deformed and the first and second core portions are located in series with respect to a flow path for the common fluid through the first and second core portions.

15. The method of claim 14 further comprising the step of connecting the first and second manifolds of at least one of the header pipes to each other at a location spaced from the cut portion after step c).

16. The method of claim 14 further comprising the step of brazing the first and second core sections and the pair of elongated header pipes as an assembly prior to step c).

17. The method of claim 14 further comprising the step of brazing the first and second core sections and the pair of elongated header pipes as an assembly prior to step b).

18. The method of claim 14 further comprising the steps of:

d) providing the heat exchanger with a third core section extending between the pair of elongate header pipes, with each of the header pipes having a third fluid manifold for the third core section;

e) providing an additional cut portion in each of the header pipes at a location between the third fluid manifold and one of the first and second fluid manifolds, the additional cut portion leaving at least part of the header pipe connecting the third fluid manifold and the one of the first and second fluid manifolds of the header; and

f) folding the heat exchanger at the additional cut portion so that the at least part of the header pipe connecting the third fluid manifold and the one of the first and second fluid manifolds is deformed and the third core section is located in series with at least one of the first and second core sections with respect to a flow path for the common fluid through the third core section and the at least one of the first and second core sections.

19. A method of making a pair of heat exchangers for transferring heat between a first fluid and a common fluid in one of the heat exchangers and between a second fluid and the common fluid in the other of the heat exchangers, the method comprising the steps of:

a) providing a heat exchanger with first and second core sections extending between a pair of elongated header pipes, with each of the pipes having a first fluid manifold for the first core section and a second fluid manifold for the second core section; and

b) completely severing each of the header pipes at a location between the first and second fluid manifolds to form the pair of heat exchangers, with one heat exchanger comprising the first fluid manifolds and the first core section, and the other heat exchanger comprising the second fluid manifolds and the second core section.

20. The method of claim 19 further comprising the step of securing the pair of heat exchangers to each other so that the first and second core portions are located in series with respect to a flow path for the common fluid through the pair of heat exchangers after step b).