Heat exchanger assembly

Abstract

A heat exchanger assembly includes a first manifold having a first manifold body with an outer wall defining a cavity and an inner partition wall integrally formed with the outer wall to define a distribution chamber disposed within the cavity. A second manifold defines a hollow cavity and is in spaced and substantially parallel relationship with the first manifold. A plurality of flow tubes extend between and fluidly connect the cavities of the manifolds. The inner partition wall has a plurality of apertures fluidly connecting the distribution chamber with the cavity. A method of manufacturing the first manifold includes the steps of extruding the manifold body, forming a plurality of openings in the outer wall, forming a plurality of apertures in the inner partition wall, inserting a separator in the manifold body, and mounting the end cap to one end of the first manifold body.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat exchanger assembly and method of manufacturing a manifold.

2. Description of the Prior Art

Heat exchanger assemblies are widely used in a variety of applications, and can be either single mode or dual mode, depending on whether functioning solely as either a condenser or an evaporator, or if functioning as both. The heat exchanger assemblies generally include a pair of manifolds fluidly connected by a plurality of flow tubes. Heat dissipating structures, such as fins, are generally disposed between the flow tubes to add surface area to the heat exchanger assembly for further aiding in heat transfer to or from ambient air passing over the flow tubes. Refrigerant enters the heat exchanger assembly through one or more ports which are connected to one or both manifolds. Refrigerant passes through the heat exchanger assembly and is exited through one or more ports connected to one or both of the manifolds.

One of the primary goals is to maximize heat exchange efficiency by managing the velocity and distribution of the refrigerant, as well as the temperature and pressure differences within the manifolds and the flow tubes. A difficulty arises because the flow characteristics of the refrigerant vary depending on the phase, that is, whether the refrigerant is a gas, liquid, or a combination. When there is poor refrigerant distribution and circulation, some sections of the heat exchanger assembly can be flooded with refrigerant and some can be starved, resulting in unequal heat transfer between portions of the heat exchanger and can cause icing or frosting of portions of the heat exchanger, further diminishing performance.

The largest problems exist when the heat exchanger assembly is operating as an evaporator. The refrigerant enters the heat exchanger assembly in two-phases, comprising liquid and gas. As the two-phase refrigerant circulates through the heat exchanger, the refrigerant absorbs heat from the ambient air passing over the flow tubes and other heat conducting structures, causing the liquid to further evaporate and the gas phase to further expand. Momentum effects due to large mass differences between the liquid and gas phases causes separation of the two-phase refrigerant. Separation of the phases adds to the already present distribution problem within the passes, which further decreases overall heat exchange performance of the evaporator.

Manufacturing costs, particularly assembly costs, can be high because of the number of components, and the precision with which they must be installed to insure proper alignment. Further, manifolds constructed of multiple parts, include joints which can be prone to failure.

Several approaches have been employed to address the problem of refrigerant distribution in heat exchanger assemblies operating as evaporators, as well as the problem of assembly cost. Examples of these heat exchanger assemblies are disclosed in U.S. Pat. No. 5,203,407 to Nagasaka, U.S. Patent Publication 2004/0194312 A1 to Gowan et al., U.S. Pat. No. 6,830,100 B2 to Gowan et al., U.S. Pat. No. 5,941,303 to Gowan, et al., and U.S. Pat. No. 1,684,083 to Bloom.

The Nagasaka '407 patent Application discloses manifolds divided into chambers for maximizing heat exchanger assembly efficiency whether a refrigerant is circulated at a high or low flow rate. The refrigerant enters the inlet port of the manifold and the chambers direct the refrigerant circulation throughout the heat exchanger assembly. The chambers do not solve the problem related to refrigerant distribution within individual flow tubes.

The Gowan '312 patent Application and '100 patent Publication disclose an extruded manifold which reduces the number of components, however they fail to include any structure to aid in the distribution of the refrigerant.

The Gowan '303 patent Application discloses an extruded manifold for a heat exchanger assembly used as either condensers or evaporators. The manifold body includes longitudinal partitions forming a plurality of longitudinal passages to direct refrigerant within the manifold. Again, the number of components is reduced, but a structure to aid in the distribution of the refrigerant is not included.

The Bloom '083 patent Application, discloses a distribution tube disposed within a manifold of a heat exchanger assembly, specifically, a refrigerating coil. The distributor tube forms a distribution chamber and includes a plurality of apertures for distributing refrigerant entering the manifold. The distribution tube is a separate component joined to the manifold by welding, and thus the problems related to assembly costs and the difficulty of positive placement of the distribution tube are not addressed. Further, the shape and configuration of the resulting distribution chamber is limited.

Accordingly, an opportunity exists to produce a manifold for a heat exchanger assembly which incorporates structures that aid in the distribution of refrigerant when operating as an evaporator. In addition, it would be advantageous for the manifold to minimize components required in order to reduce assembly costs.

SUMMARY OF THE INVENTION AND ADVANTAGES

The subject invention provides a heat exchanger assembly with a first manifold having a first manifold body defining a hollow cavity. A second manifold having a second manifold body defining a hollow cavity is in spaced and substantially parallel relationship with the first manifold. A plurality of flow tubes extend between and fluidly connect the cavities of the manifolds for passing refrigerant between the manifolds. The first manifold body has an outer wall defining the cavity and an inner partition wall disposed within the cavity adjacent the outer wall with the inner partition wall having a section integrally formed with a portion of the outer wall to define a distribution chamber disposed within the cavity with the inner partition wall having a plurality of apertures fluidly connecting the distribution chamber with the cavity.

The subject invention also provides a method of manufacturing a manifold having a manifold body with an outer wall defining a hollow cavity, an inner partition wall with a plurality of apertures and at least one end cap, including the following steps: extruding the manifold body having the outer and inner partition walls with the inner partition wall integrally connected to the outer wall to form a distribution chamber within the cavity; cutting the manifold body to a pre-determined length; forming a plurality of openings in the outer wall; forming a plurality of apertures in the inner partition wall aligned with the openings in the outer wall; and mounting the end cap to at least one end of the manifold body.

The production of an extruded single-piece manifold body which includes an integral distribution chamber, allows for the positive location of the distribution chamber, and more robust construction than designs using multiple pieces by including a distribution chamber as an integral part of the manifold body. Incorporation of the distribution chamber in the single piece construction, also results in the reduction of manufacturing costs by reducing the number of parts required, and avoids problems associated with mechanical assembly, location and joining of separate distribution tubes, in particular, for longer manifolds.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view of a heat exchanger assembly;

FIG. 2 is a fragmented perspective view of a first manifold of the heat exchanger assembly, illustrating an inner partition wall;

FIG. 3 is a cross-sectional top view of one embodiment of the manifold;

FIG. 4 is a cross-sectional top view of another embodiment of the manifold;

FIG. 5 is a cross-sectional top view of another embodiment of the manifold;

FIG. 6 is a cross-sectional top view of another embodiment of the manifold;

FIG. 7 is a cross-sectional top view of another embodiment of the manifold;

FIG. 8 is a cross-sectional top view of another embodiment of the manifold;

FIG. 9 is a cross-sectional top view of another embodiment of the manifold;

FIG. 10 is a cross-sectional top view of another embodiment of the manifold;

FIG. 11 is a cross-sectional top view of another embodiment of the manifold;

FIG. 12 is a cross-sectional top view of another embodiment of the manifold;

FIG. 13 is a cross-sectional top view of another embodiment of the manifold;

FIG. 14 is a fragmented side view of the manifold illustrating one embodiment of a port connected to the manifold;

FIG. 15 is a fragmented side view of the manifold illustrating another embodiment of a port connected to the manifold;

FIG. 16 is a fragmented side view of the manifold illustrating another embodiment of a port connected to the manifold;

FIG. 17 is a fragmented side view of the manifold illustrating another embodiment of a port connected to the manifold;

FIG. 18 is a cross-sectional side view of the manifold including separators.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a heat exchanger assembly is generally shown at 20 in FIG. 1. The heat exchanger assembly 20 includes a first manifold 22, a second manifold 52, a plurality of flow tubes 42 fluidly connecting the manifolds 22, 52, and a plurality of heat conducting structures, here illustrated as fins 44. The first manifold 22 includes a first manifold body 24 having a length with a first end 58 and a second end 60. An end cap 26 is shown being attached to each end 58, 60 of the first manifold body 24. The end cap 26 can include a cladding material, and can be joined to the first manifold body 24 using a variety of methods, such as but not limited to, brazing or welding. It can be readily appreciated that the first manifold body 24 can include an end produced as part of an extrusion process. As is known to those skilled in the art, the first manifold 22 may be commonly referred to as an inlet manifold, therefore performing an inlet function, and the second manifold 52 may be commonly referred to as an outlet manifold, therefore performing an outlet function, however, the opposite could be true. Reference to the first and second manifolds 22, 52 is interchangeable in the description of the subject invention.

The second manifold 52 includes a second manifold body 54 and defines a hollow cavity 31. The second manifold 52 has a length with a first end 62 and a second end 64 and is in spaced and substantially parallel relationship with the first manifold 22. It can be readily appreciated that though the second manifold 52 is shown as having the same general appearance as that of the first manifold 22, the second manifold 52 can be constructed differently than the first manifold 22, for example, but not limited to, the second manifold 52 can comprise multiple joined pieces. End caps 26 are shown being attached to each end 62, 64 of the second manifold body 54. The end cap 26 can include a cladding material, and can be joined to the second manifold body 54 using a variety of methods, such as but not limited to, brazing or welding. It can be readily appreciated that the second manifold body 54 can include an end produced as part of an extrusion process. Though the heat exchanger assembly 20 is shown throughout the drawings with the manifolds 22, 52 being vertically oriented, it can be readily appreciated that the heat exchanger assembly 20 can be oriented in a variety ways to accommodate engineering requirements of a specific application, for instance, horizontal.

A plurality of flow tubes 42 extend between and fluidly connect the cavities 30, 31 of the manifolds 22, 52 for passing refrigerant between the manifolds 22, 52. Referring to FIG. 2, the outer wall 28 includes a plurality of openings 40 sized for accepting the plurality of flow tubes 42. The openings 40 are typically elongated slots, however different shapes can be used, such as but not limited to, circles and squares. The flow tubes are disposed within the cavity 30 of the first manifold 22 fluidly connecting the cavity 31 of the second manifold 52 to the cavity 30 of the first manifold 22.

Referring to FIG. 2, the first manifold body 24 has an outer wall 28 defining a cavity 30 and an inner partition wall 32 disposed within the cavity 30 adjacent to the outer wall 28. The inner partition wall 32 has a section 34 integrally formed with a portion of the outer wall 28 to define a distribution chamber 36 disposed within the cavity 30. The inner partition wall 32 has a plurality of apertures 38 fluidly connecting the distribution chamber 36 with the cavity 30. The first manifold body 24 is shown being generally cylindrical, however many shapes are possible. Referring to FIG. 9, a first thickness T₁ of the inner partition wall 32 and second thickness T₂ of the outer wall 28 can be the same or can be different from one another. In addition, the second thickness T₂ of the outer wall 28 can be uniform or may vary. Similarly, the first thickness T₁ of the inner partition wall 32 can be uniform or may vary. It can be readily appreciated that it may be advantageous to have different wall thicknesses T₁, T₂ in different locations of the first manifold body 24. A reduced first thickness T₁ may be possible because of the lower operating pressure between the cavity 30 and the distribution chamber 36, and can save space and weight. The second thickness T₂ may be generally dictated by burst strength requirements. Reduced thickness T₁, T₂ in the inner partition wall 32 and the outer wall 28 could be used to facilitate formation of the plurality of openings 40 and the plurality of apertures 38, and thicker regions can be used elsewhere to provide structural support, as shown in FIG. 9. Though the cross-section of the outer wall 28 is generally illustrated as being circular, it can be readily appreciated that the outer wall 28 can be a variety of shapes, for instance and referring to FIG. 12, the outer wall 28 can include a protrusion resulting in the outer wall 28 itself defining a majority of the distribution chamber 36.

The distribution chamber 36 has a length generally defined by the length of the first manifold body 24. Modifications can be made to the length of the distribution chamber 36, for instance, by inserting a separator 48 into the distribution chamber 36, which closes off a portion of the chamber 36. Alternatively, the effective length of the distribution chamber 36 can be shortened by selectively eliminating some of the plurality of apertures 38 in an unnecessary area. The distribution chamber 36 is substantially parallel to the first manifold body 24. Referring to FIG. 3, the inner partition wall 32 has a generally C-shaped cross-section. Referring to FIGS. 4-13, it can be readily appreciated that the cross-section of the inner partition wall 32 may have many shapes, including but not limited to, arc-like, linear, D-shaped, and a pyramid. The distribution chamber 36 can be disposed within the cavity 30 directly opposite the plurality of openings 40 where the plurality of flow tubes 42 are inserted into the first manifold body 24. Referring to FIGS. 7-8, it can be appreciated that the distribution chamber 36 can also be located in different positions within the cavity 30 to accommodate variations in plumbing, flow and refrigerant distribution requirements. The plurality of apertures 38 are disposed within the inner partition wall 32 generally run along the length of the distribution chamber 36 and are generally aligned with the plurality of openings 40 in the outer wall 28, but can vary depending on performance requirements. The plurality of apertures 38 can comprise a variety of shapes and sizes, including but not limited to, circles and polygons. A flat ledge 50 can be included along the length of the inner partition wall 32 disposed within the cavity 30, for locating and forming the plurality of apertures 38.

At least one port may be in the first manifold 22 and fluidly connected to at least one of the distribution chamber 36 and the cavity 30. The port may be an orifice or a tube, as is known in the art. The port may be an inlet, an outlet, or a combination of both. Referring to FIG. 1, one of the ports is an inlet port 56 and is fluidly connected to the first manifold 22 for introducing refrigerant into the heat exchanger and another one of the ports is an outlet port 57 and is fluidly connected to the second manifold 52 for exiting refrigerant from the heat exchanger assembly 20. Referring to FIGS. 14 and 16, the preferred embodiment includes the port 56, 57 fluidly connected to the distribution chamber 36, either through the end cap 26 or the outer wall 28. Referring to FIGS. 15 and 17, in another embodiment, the port 56, 57 can be fluidly connected to the cavity 30 of the first manifold 22 through the outer wall 28 or through the end cap 26. It can be appreciated that the ports 56, 57 can include a coupler 66. The coupler 66 may be useful for connecting external plumbing to the heat exchanger assembly 20 and may also be useful for manufacturing purposes. It can further be appreciated that the ports 56, 57 can be fluidly connected to the second manifold 52 as described for the first manifold 22, depending on the engineering requirements of a specific application. It can further be appreciated that more than one inlet port 56 can be connected to the heat exchanger assembly 20 to introduce refrigerant into the heat exchanger assembly 20 and more than one outlet port 57 can be used to exit refrigerant from the heat exchanger assembly 20. Referring to FIG. 18, a separator 48 can be inserted within the cavity 30, 31 and/or distribution chamber 36, further dividing the cavity 30, 31 and distribution chamber 36.

The present invention also provides a method of manufacturing a manifold having a first manifold body 24 with an outer wall 28 defining a hollow cavity 30, an inner partition wall 32 with a plurality of apertures 38 and at least one end cap 26. The method includes the step of extruding the first manifold body 24 which has an outer wall 28 and an inner partition wall 32 with the inner partition wall 32 integrally connected to the outer wall 28 to form a distribution chamber 36 within the cavity 30. The method further includes the step of cutting the first manifold body 24 to a predetermined length. Cutting can be accomplished by any means. The method further includes forming a plurality of openings 40 in the outer wall 28. The openings 40 can be formed by a variety of means, including, but not limited to, drilling, lancing or punching. The method further includes forming a plurality of apertures 38 in the inner partition wall 32 aligned with the openings 40 in the outer wall 28. The method further includes inserting a separator 48 into the manifold body 24. It can be appreciated that the separator 48 can be slid into the distribution chamber 36 or the cavity 30 or alternatively that the separator 48 can be inserted through a slot 49 formed in the outer wall 28. It can further be appreciated that more than one separator 48 can be inserted, and the separator 48 can span the distribution chamber 36, the cavity 30 or both 30, 36. The method further includes mounting the end cap 26 to one end of the first manifold body 24.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims. The reference numerals are merely for convenience and are not to be read in any way as limiting.

Claims

1. A heat exchanger assembly comprising:

a first manifold having a first manifold body defining a hollow cavity;

a second manifold having a second manifold body defining a hollow cavity and in spaced and substantially parallel relationship with said first manifold;

a plurality of flow tubes extending between and fluidly connecting said cavities of said manifolds for passing refrigerant between said manifolds; and

said first manifold body having an outer wall defining said cavity and an inner partition wall disposed within said cavity adjacent said outer wall with said inner partition wall having a section integrally formed with a portion of said outer wall to define a distribution chamber disposed within said cavity with said inner partition wall having a plurality of apertures fluidly connecting said distribution chamber with said cavity.

2. An assembly as set forth in claim 1 wherein said inner partition wall has a generally C-shaped cross-section.

3. An assembly as set forth in claim 1 wherein a length of said distribution chamber is defined by a length of said first manifold body.

4. An assembly as set forth in claim 3 wherein said distribution chamber is substantially parallel to said first manifold body.

5. An assembly as set forth in claim 1 having at least one port in said first manifold and fluidly connected to at least one of said distribution chamber and said cavity.

6. An assembly as set forth in claim 5 wherein said port is adjacent at least one of said outer wall and an end cap of said first manifold.

7. An assembly as set forth in claim 6 wherein said at least one port further includes a coupler adjacent at least one of said outer wall and said end cap and fluidly connected to at least one of said distribution chamber and said cavity.

8. An assembly as set forth in claim 1 wherein said outer wall includes a plurality of openings sized for accepting said plurality of flow tubes.

9. An assembly as set forth in claim 8 wherein said apertures in said inner partition wall are aligned with said openings in said outer wall.

10. An assembly as set forth in claim 8 wherein said flow tubes are mounted in said openings and disposed within said cavity of said first manifold fluidly connecting said second manifold to said cavity of said first manifold.

11. An assembly as set forth in claim 1 wherein said inner partition wall has a first thickness different than a second thickness of said outer wall.

12. A manifold assembly comprising:

an outer wall defining a hollow cavity; and

an inner partition wall disposed within said cavity adjacent said outer wall with said inner partition wall having a section integrally formed with a portion of said outer wall to define a distribution chamber disposed within said cavity with said inner partition wall having a plurality of apertures fluidly connecting said distribution chamber with said cavity.

13. An assembly as set forth in claim 12 wherein said inner partition wall has a generally C-shaped cross-section.

14. An assembly as set forth in claim 12 wherein a length of said distribution chamber is defined by a length of said outer wall.

15. An assembly as set forth in claim 14 wherein said distribution chamber is substantially parallel to said outer wall.

16. An assembly as set forth in claim 12 having at least one port in said first manifold and fluidly connected to at least one of said distribution chamber and said cavity.

17. An assembly as set forth in claim 16 wherein said port is adjacent at least one of said outer wall and an end cap of said first manifold.

18. An assembly as set forth in claim 17 wherein said inlet port further includes a coupler adjacent at least one of said outer wall and said end cap and fluidly connected to at least one of said distribution chamber and said cavity for introducing refrigerant into said first manifold.

19. An assembly as set forth in claim 12 wherein said outer wall includes a plurality of openings sized for accepting a plurality of flow tubes.

20. An assembly as set forth in claim 19 wherein said apertures in said inner partition wall are aligned with said openings in said outer wall.

21. An assembly as set forth in claim 12 wherein said inner partition wall has a first thickness different than a second thickness of said outer wall.

22. A method of manufacturing a manifold having a manifold body with an outer wall defining a hollow cavity, an inner partition wall with a plurality of apertures and at least one end cap, said method comprising the steps of:

extruding the manifold body having the outer wall and inner partition wall with the inner partition wall integrally connected to the outer wall to form a distribution chamber within the cavity;

cutting the manifold body to a pre-determined length;

forming a plurality of openings in the outer wall;

forming a plurality of apertures in the inner partition wall aligned with the openings in the outer wall;

inserting a separator into the manifold body; and

mounting the end cap to one end of the manifold body.