US20070204982A1

US20070204982A1 - Manifolds and manifold connections for heat exchangers

Info

Publication number: US20070204982A1
Application number: US11/366,325
Authority: US
Inventors: Terry Barnes; Naveen Bhojraj; Cowley Phillips
Original assignee: R-SQUARED PUCKETT Inc
Current assignee: R-SQUARED PUCKETT Inc
Priority date: 2006-03-02
Filing date: 2006-03-02
Publication date: 2007-09-06

Abstract

Manifolds and manifold connections for heat exchangers are disclosed. One embodiment includes an elongate tubular body with a central cavity. The body has an elongate retainer formed therealong. An attachment member is received by the retainer and an insert is retained between the tubular body and the attachment. The insert is formed from a material having a melting temperature less than that of the tubular body and the attachment member. The manifold may be heated to a temperature greater than the melting temperature of the insert material and subsequently cooled so that the insert joins the attachment member to the body.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates to heat exchangers, more particularly to manifolds and manifold connections of heat exchangers.
2. Background Art
Heat exchangers generally are units wherein a first fluid is conveyed in close proximity to a second fluid of a different temperature, such that heat is exchanged from one fluid to another. Heat exchangers generally include condensers, evaporators, radiators, oil coolers and heater cores, which employ manifolds that are utilized for conveying a fluid therein. The manifolds are typically formed from a material that is both conductive and structurally adequate to retain the fluid therein for an exchange of heat to or from a fluid external of the manifold.
An aspect of the prior art is to form manifolds from clad sheets of aluminum that include a first layer of American National Standards Institute (ANSI) designation such as 3003, and a second layer with an ANSI designation such as 4047. The first layer provides the structural aluminum of the manifold and the second layer provides a filler material for brazing the first layer to another component. The second layer, the filler material, is often referred to as the clad sheet and generally forms a partial thickness of the first layer.
Clad sheets are relatively costly to fabricate requiring a billet of the clad layer placed upon a billet of the structural layer with multiple cold forming operations to result in the final clad sheet. The clad sheet is then shaped into a portion of the manifold and bonded to other components by heating the manifold until the clad sheet melts, thereby brazing the components to result in a sealed manifold and heat exchanger.

SUMMARY OF THE INVENTION

An aspect of the present invention is to provide a manifold for a heat exchanger. The manifold has an elongate tubular body with a central cavity formed therethrough. The tubular body has an elongate retainer formed at least partially upon the body. An attachment member has an end received by the retainer, and an insert is retained between the tubular body and the attachment member. The insert is formed from a material having a melting temperature that is less than that of the tubular body and the attachment member.
Another aspect of the present invention is to provide a method for manufacturing a manifold for a heat exchanger. The method includes extruding a tubular body with a retainer. A sheet is provided on the tubular body in cooperation with the retainer. The sheet has a melting temperature less than the tubular body. An aperture is formed through the tubular body and the sheet. A distal end of a second tubular body is inserted through the aperture. The manifold is heated to a temperature greater than the melting temperature of the sheet so that the sheet material seeps between the second tubular body and the first tubular body aperture. The manifold is cooled so that the insert joins the second tubular body to the first tubular body aperture.
The above aspects, and other aspects, embodiments, objects, features, and advantages of the present invention are readily apparent from the following detailed description of embodiments of the invention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a vapor-compression cycle utilizing heat exchangers in accordance with the present invention;
FIG. 2 is a schematic view of a parallel flow heat exchanger in accordance with the present invention;
FIG. 3 is an axial end view of a portion of a manifold of a heat exchanger in accordance with the present invention, illustrated with an insert therefore;
FIG. 4 is another axial end view of the portion of the manifold of FIG. 3, illustrated partially assembled;
FIG. 5 is yet another axial end view of the portion of the manifold of FIG. 3, illustrated during a manufacturing process in cooperation with a punch;
FIG. 6 is another axial end view of the portion of the manifold of FIG. 3, illustrated during the manufacturing process in cooperation with the punch of FIG. 5;
FIG. 7 is a partially exploded perspective view of the portion of the manifold of the heat exchanger of FIGS. 3-6, illustrated in cooperation with further manifold components;
FIG. 8 is a section view of the manifold of FIG. 7;
FIG. 9 is another cross-section view of a manifold of a heat exchanger in accordance with the present invention; and
FIG. 10 is an axial end view of another manifold of a heat exchanger in accordance with the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art to variously employ the present invention.
Referring now to FIG. 1, a simple vapor-compression cycle is illustrated and referenced generally by numeral 20. The cycle 20 includes a compressor 22, such as a pump, which pumps fluid through the cycle 20 in the direction of the arrows illustrated in the figure. The compressor 22 pumps the fluid to a first heat exchanger, illustrated by condenser 24. The fluid is condensed by the compressor 22 thereby exchanging heat from the fluid in the condenser 24 to a second fluid passing through the condenser 24. The fluid is subsequently conveyed to an expansion valve 26 whereby the pressure imparted by the compressor 22 is reduced. Next, the fluid is conveyed into another heat exchanger such as an evaporator 28. At the evaporator 28, the fluid within the cycle 20 is heated by an external fluid that causes the fluid within the cycle 20 to evaporate, thereby absorbing the heat from the external fluid of the evaporator 28. The fluid within the cycle 20 is subsequently compressed by the compressor 22 and the heat absorbed at the evaporator 28 is thereby released at the condenser 24.
The cycle 20 illustrated in FIG. 1 is a simple vapor-compression cycle for illustrating exemplary uses of heat exchangers such as the condenser 24 and the evaporator 28. The cycle 20 may be representative of a refrigeration cycle wherein the compressor 22 pressurizes refrigerant for releasing of heat at the condenser 24 to ambient air external of the refrigerator. The pressure of the refrigerant is released at the expansion valve 26 and the refrigerant evaporates within the evaporator 28 within the refrigerator for absorbing heat from the refrigerator and thereby conveying the heated refrigerant to the compressor 22.
Likewise, the cycle 20 may be representative of a cooling system for a vehicle whereby coolant is evaporated at the evaporator 28 or the engine of the vehicle. The pump or compressor 22 pressurizes the coolant in the condenser 24 or radiator such that the heat is transferred through the condenser or radiator 24 to air that passes through the radiator or is forced through the radiator. The pressure on the coolant is subsequently reduced in expansion valve 26 and the cycle 20 continues.
Although a vapor-compression cycle is illustrated and specific heat exchanger applications are described, the invention contemplates that the present invention may be utilized with various heat exchangers and various cycles that incorporate heat exchangers in accordance with the present invention.
Referring now to FIG. 2, a heat exchanger 30 is illustrated in accordance with the present invention. The heat exchanger 30 may be utilized for the condenser 24 and/or the evaporator 28 in the cycle 20 illustrated in FIG. 1. The heat exchanger 30 is illustrated schematically as a parallel flow heat exchanger, which conveys fluid, such as a heated fluid, through an inlet 32 of a first header tube 34. The first header tube 34 is a manifold, conveying the fluid from the header tube 34 through a series of parallel secondary tubes 36, such as baffles, or the like. As the heated fluid is conveyed through the secondary tubes 36, a second fluid, such as air, is conveyed through gaps between the secondary tubes 36 for exchanging heat from the heated fluid within the secondary tubes 36 to the air forced about the secondary tubes 36. The heated fluid, which is now cooled through the convection of the air about the secondary tubes 36, is collected in a second header tube 38 which also acts as a manifold, thereby collecting the pressurized fluid and conveying through outlet 40 to a subsequent stage in the cycle, such as to the expansion valve 26.
Alternatively, the heat exchanger 30 may be utilized for conveying a coolant through the inlet of the first header tube 34. The coolant is conveyed through the secondary tubes 36, whereby a heated fluid is forced about the secondary tubes 36 for heating the coolant within the secondary tubes 36 until the heated coolant evaporates. The heated and evaporated coolant is conveyed into the second header tube 38 and subsequently through the outlet 40 through the cycle, such as cycle 20 to the compressor 22.
Although an evaporator and condenser are described with parallel flow, the invention contemplates that the manifold of the present invention may be utilized with any heat exchanger regardless of direction of flow, such as heater cores, radiators, air conditioner units, and the like.
By utilizing multiple secondary tubes 36, convection or conduction is improved between the fluid passing through the secondary tubes 36 and the fluid flowing about the secondary tubes 36 due to the enlarged surface area derived by the multiple secondary tubes 36. Additionally, the secondary tubes 36 may include heat fins 41 for conduction from the secondary tubes 36 to the heat fins 41 thereby improving convection or conduction from the fluids forced about the heat fins 41 and secondary tubes 36.
The prior art has found that various conductive alloys may be utilized for heat exchangers for optimizing both the structural integrity of the heat exchanger and conduction and convection through the heat exchanger. One such conductive material is an aluminum alloy. In order to bond aluminum alloy manifolds, such as an aluminum alloy header tube 34, 38 to aluminum alloy secondary tubes 36, prior art header tubes 34, 38 have been developed from clad sheets for providing the filler material for brazing secondary tubes 36 to header tubes 34, 38. Due to the cost and complexities associated with developing clad sheets and forming the clad sheets in the header tubes, considerable cost, manufacturing time, and resources are utilized for developing prior art heat exchangers.
Referring now to FIG. 3, a portion of a manifold for a heat exchanger is illustrated in accordance with the present invention. A portion of the manifold includes an elongate tubular body, such as a header tube 42 of the heat exchanger. Although header tube 42 is described, the invention contemplates that any tubular body within a heat exchanger manifold may be utilized in accordance with the present invention.
The header tube 42 may be formed with a continuous profile, with a central cavity 44 formed therethrough for conveying fluid within the heat exchanger. The tubular body of the header tube 42 is illustrated forming a generally D-shaped profile with an arcuate region 46 spaced apart from a mounting region 48 by a pair of sidewalls 50, 52. The header tube 42 may include a pair of gibs 54, 56 extending inboard from distal ends of the sidewalls 50, 52 and extending over the mounting region 48. The gibs 54, 56 are formed lengthwise along the header tube 42 for providing an elongate slot along the header tube 42 for retaining other manifold components.
The header tube 42 may be formed from an extrusion process for providing uniform profile tubular members, thereby providing modularity for tubing and manifolds within heat exchangers.
A sheet 58 of filler metal may be provided separately from the header tube 42. The sheet 58 may disposed between the gibs 54, 56 in the mounting region 48 of the header tube 42, as illustrated in FIG. 4. The sheet 58 has a melting temperature less than that of the header tube 42 for brazing ancillary components to the header tube 42. Unlike the prior art, the sheet 58 is applied only to regions that will receive an attachment such as a secondary tube, fitting, bracket, or the like. Therefore, much less filler metal is required than filler metal that is clad to entire interior or exterior surfaces of prior art header tubes. Additionally, extruded header tubes require less manufacturing time, resources and costs in comparison to clad sheets that are cold formed, rolled and subsequently seam welded for brazing the header tubes along their lengths. By extruding the header tube, instead of forming it from a sheet material that is subsequently brazed together along a seam, the burst pressure of the central cavity 44 is increased for a given wall thickness.
The header tube 42 may be formed from an aluminum alloy having an ANSI designation such as 3003 and the insert sheet 58 may be formed from an aluminum alloy having an ANSI designation such as 4047. Accordingly, the melting temperature of the sheet 58 is approximately 1080 degrees Fahrenheit, which is less than the melting temperature of the header tube 44, which is 1150-1200 degrees Fahrenheit. Thus, after an ancillary component is attached to the header tube 42, the manifold is heated to a temperature greater than 1080 degrees Fahrenheit, such that the insert sheet 58 melts and flows between the connection thereby brazing the components together at a manifold joint. Of course, the insert 58 may be utilized to solder or otherwise join an ancillary component to the manifold.
The insert sheet 58 may be formed of any contour that is adequate for the prescribed application. For example, the sheet 58 may be provided with an arcuate contour to match the profile between the gibs 54, 56 and the mounting region 48. The mounting region 48 may include a pair of recesses 60, 62, each displaced beneath one of the gibs 54, 56 for facilitating the flow of filler of the insert 58 as it melts. Additionally, the recesses 60, 62 may also facilitate drainage of environmental solutions that may collect upon the header tube 42, such as precipitation and road salts. Since road salts act as an insulator upon the header tube 42, the recesses 60, 62 assist in the flow of road salts and precipitation along and from the header tube 42. Alternatively, the mounting region 48 may have a central projection for facilitating the flow of filler.
With reference now to FIG. 5, the gibs 54, 56 may be deformed towards the corresponding recesses 60, 62 to mechanically clinch the insert to the mounting region 48. The deformation may be provided by a subsequent extrusion process, stamping process, rolling process, or the like. The deformation ensures the location of the inserts 58 prior to subsequent manufacturing operations. Once the gibs 54, 56 are flattened to the recesses 60, 62 of the mounting region, a uniform wall thickness is provided without seams, which are common in prior art manifolds.
Alternatively, the filler sheet 58 may have a width greater than the slot provided between gibs 54, 56 to provide an interference fit. Thus, one sheet 58 or multiple sheets 58 may be inserted between the gibs 54, 56 and temporarily retained at the desired location due to the interference fit.
The insert sheets 58 may be provided as solid sheets, and an aperture may be subsequently formed therethrough, if necessary, when an aperture is formed through the mounting region 48 of the header tube 42. For example, if a secondary tube or fitting were to be inserted through the mounting region 48, a corresponding aperture may be formed concurrently through the insert sheet 58 and the mounting region 48 of the header tube 42. Accordingly, a punch 64 may be provided as illustrated in FIG. 5, for punching apertures concurrently through the header tube mounting region 48 and the insert sheet 58. The punch 64 may be provided with a cutting edge 66 for translation to a second position that is illustrated in FIG. 6 for punching an aperture 70 through the mounting region 48 and an aperture 72 through the insert sheet 58. Depending on the size of the apertures, the punch 64 may also punch the mounting region aperture 70 through the gibs 54, 56.
Alternatively, the insert sheet 58 may be formed with an aperture therethrough, which is subsequently aligned with the corresponding aperture to the mounting region 48 of the header tube 42.
Referring now to FIG. 7, a portion of a manifold 68 is illustrated partially exploded with the header tube 42 and a series of insert sheets 58. The aperture 70 formed through the mounting region 48 of the header tube 42 defines a port for fluid communication out of the central cavity 44 of the header tube 42. Likewise, the aperture 72 formed through the insert sheet 58 provides access to the aperture 70 of the mounting region 48.
As illustrated in FIG. 7, inserts 58 may be provided along the header tube 42 where required for subsequent installation of attachment members, such as secondary tubes 74. Although two secondary tubes 74 are illustrated, the invention contemplates any number of attachment members such as the secondary tubes 74, fittings, brackets, or the like. For example, an entire series of secondary tubes 74 may be attached to the header tube for a parallel flow heat exchanger such as that schematically illustrated in FIG. 2. Although a linear extension is illustrated as the header tube 42, the invention contemplates any elongate contour, including non-linear and any manufacturing process for formation, such as rolling.
Referring now to FIG. 8, a cross-section view of the manifold 68 is illustrated with the secondary tube 74 extending partially into the central cavity 44 of the header tube 42. The clearance between the aperture 70 of the mounting region 48 and the secondary tube 74 may be generally associated with a slip-fit cooperation, which is generally 0.01 inches or less. The cross-section of FIG. 8 illustrates the cooperation of the header tube 42, secondary tube 74, and filler sheet 58 prior to the brazing process.
Once assembled, the manifold 68 is placed within a furnace, kiln, or the like for heating the manifold 68 to a predefined temperature. In one embodiment, the insert sheet 58 is formed from a raw aluminum alloy with an ANSI designation of 4047, which has a melting temperature of approximately 1080 degrees Fahrenheit. Accordingly, the manifold 68 is heated to a temperature of approximately 1140 degrees Fahrenheit, which is greater than the melting temperature of the insert 58 but less than the melting temperature of the secondary tube 74 and the header tube 42. Thus, the insert 58 melts and flows between the joint of the aperture 70 and the mounting region 48 and the secondary tube 74. The brazed joint joins the secondary tube 74 to the header tube 42 and seals the joint therebetween for sealed fluid communication of fluid through the header tube central cavity 42 and the secondary tube 74.
Although secondary tubes 74 are illustrated, the invention contemplates utilization of various attachment members in accordance with the present invention. For example, various tubular members may be employed such as baffles, or non-linear tubing. Due to the modularity of the coextruded header tube 42 and gibs 54, 56, various exchanger manifold 68 applications and configurations are contemplated within the spirit and scope of the present invention.
Referring now to FIG. 9, the manifold 68 is illustrated in cooperation with another tubular member, namely a fitting 76. The aperture 70 in the mounting region 48 is sized to receive an end of the fitting 76. Likewise, the aperture 72 in the insert sheet 58 is also sized to receive the fitting 76. Since fittings, such as fitting 76, typically have a cylindrical body, the insert sheet 58 may be in the shape of an insert ring.
Similar to the prior embodiment, the fitting 76 has a melting temperature greater than that of the insert sheet 58. Once the manifold 68 is assembled, as illustrated in FIG. 9, the manifold 68 is heated to a temperature greater than the melting temperature of the insert 58 so that it adheres to the fitting 76 and the mounting region 48 of the header tube 42 and seeps between the interconnection of the fitting 76 and the mounting region aperture 70 through capillary action. Once the manifold 68 is cooled, the filler sheet material brazes the fitting 76 to the header tube 42 for fluid communication through the fitting 76 and the header tube 42 that is sealed at the joint.
Referring now to FIG. 10, the manifold 68 of the present invention is illustrated in cooperation with a bracket 78. The bracket 78 may be utilized for fastening the manifold 68 to another component, for example for mounting a radiator or heater core to a vehicle chassis, or for mounting a condenser or evaporator to an appliance, or the like. The bracket 78 may be stamped, extruded, cold formed, or formed from any suitable manufacturing process. The bracket 78 includes a mounting flange 80, which is sized to be received between the gibs 54, 56 and the mounting region 48 of the header tube 42. The bracket 78 may be inserted at an axial end of the header tube 42 and translated to a corresponding mounting position. Likewise, an insert sheet 82 may be inserted beneath the flange 80 of the bracket 78. The insert sheet 82 has a melting temperature that is less than that of the bracket 78 and the header tube 42.
Once assembled, the manifold 68 is placed within a kiln so that the insert sheet 82 melts thereby brazing or soldering the bracket 78 to the mounting region 48 of the header tube 42. The insert sheet 82 may comprise filler material that flows into the recesses 60, 62 thereby joining the flange 80 of the bracket 78 to the mounting region 48.
In summary, simplified and modular manifolds and manifold connections are disclosed for heat exchangers, which are less costly than prior art manifold components and reduce the manufacturing time and resources required for fabrication.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.

Claims

1. A manifold for a heat exchanger comprising:

an elongate tubular body with a central cavity formed therethrough, the tubular body having an elongate retainer formed at least partially therealong;

an attachment member having an end received by the retainer; and

an insert retained between the tubular body and the attachment member, the insert being formed from a material having a melting temperature less than that of the tubular body and the attachment member.

2. The manifold of claim 1 wherein the manifold is heated to a temperature greater than the melting temperature of the insert material and subsequently cooled so that the insert joins the attachment member to the tubular body.

3. The manifold of claim 1 wherein the tubular body has at least one port formed therethrough, the insert has an aperture sized relative to the port and generally aligned with the port, and the attachment member further comprises a second tubular body having a distal end disposed through the insert aperture and the port for fluid communication with the tubular body central cavity.

4. The manifold of claim 1 wherein the tubular body has at least one port formed therethrough, the insert has an aperture sized relative to the port and generally aligned with the port, and the attachment member further comprises a fitting having a distal end disposed through the insert aperture and the port for fluid communication with the tubular body central cavity.

5. The manifold of claim 1 wherein the attachment member further comprises a bracket for fastening the manifold to another component.

6. The manifold of claim 1 wherein the tubular body and the retainer are coextruded.

7. The manifold of claim 1 wherein the retainer is formed along the length of the tubular body.

8. The manifold of claim 1 wherein the insert has a contour formed along the length of the insert that is sized to match a contour of the tubular body.

9. The manifold of claim 1 wherein the tubular body is formed from an aluminum alloy having an American National Standards Institute (ANSI) designation of 3003 and the insert is formed from an aluminum alloy having an ANSI designation of 4047.

10. The manifold of claim 1 wherein the retainer further comprises a pair of gibs in spaced opposition.

11. The manifold of claim 10 wherein the insert is at least partially displaced beneath the pair of gibs.

12. The manifold of claim 10 wherein the tubular body has a pair of recesses formed along its length, each displaced beneath the pair of gibs for facilitating flow of insert material after the insert has reached the melting temperature.

13. The manifold of claim 10 wherein the gibs are deformed to retain the insert.

14. The manifold of claim 10 wherein the insert has an interference fit between the gibs and the tubular body.

15. A manifold for a heat exchanger comprising:

an elongate tubular body with a central cavity formed therethrough and at least one port formed transversely through the tubular body;

an elongate retainer formed at least partially along the tubular body adjacent to the at least one port;

an insert formed from a material having a melting temperature less than that of the tubular body, the insert having an aperture formed therethrough sized relative to the port, the insert being retained by the retainer so that the insert aperture and the port are generally aligned; and

a second tubular body having a distal end disposed through the insert aperture and the port for fluid communication with the tubular body central cavity, the second tubular body being formed from a material having a melting temperature greater than that of the insert, wherein the second tubular body is attached to the first tubular body for sealed fluid communication through the port by heating the manifold to a temperature greater than the melting temperature of the insert material and cooling the manifold such that the insert brazes the second tubular body to the first tubular body.

16. The manifold of claim 15 wherein a series of ports are formed through the tubular body;

wherein the insert further comprises a series of inserts each retained to the tubular body by the retainer and each having an aperture generally aligned with one of the series of ports; and

wherein the second tubular body further comprises a series of tubular bodies, each having a distal end disposed through one of the insert apertures and the corresponding port for fluid communication with the tubular body central cavity.

17. The manifold of claim 15 wherein another port is formed through the tubular body, and the manifold further comprises:

a fitting having a distal end disposed through the insert aperture and the port for fluid communication with the tubular body central cavity, the fitting being formed from a material having a melting temperature greater than that of the insert, wherein the fitting is attached to the first tubular body for sealed fluid communication through the port by heating the manifold to a temperature greater than the melting temperature of the insert material and cooling the manifold such that the insert brazes the fitting to the first tubular body.

18. The manifold of claim 15 further comprising:

a bracket sized to be retained by the retainer for fastening the manifold to another component; and

an insert retained by the retainer, the insert being formed from a material having a melting temperature less than that of the tubular body and the bracket, wherein the bracket is attached to the first tubular body by heating the manifold to a temperature greater than the melting temperature of the insert material and cooling the manifold such that the insert brazes the bracket to the first tubular body.

19. A method for manufacturing a manifold for a heat exchanger comprising:

extruding a tubular body with a retainer;

providing a sheet on the tubular body in cooperation with the retainer, the sheet having a melting temperature less than the tubular body;

forming an aperture through the tubular body and the sheet;

inserting a distal end of a second tubular body through the aperture;

heating the manifold to a temperature greater than the melting temperature of the sheet so that the sheet material seeps between the second tubular body and the first tubular body aperture; and

cooling the manifold so that the insert brazes the second tubular body to the first tubular body aperture.

20. A manifold manufactured by the method of claim 19.