WO2009029102A1

WO2009029102A1 - Method of manufacturing brazed aluminum plate and ring heat exchanger

Info

Publication number: WO2009029102A1
Application number: PCT/US2007/077235
Authority: WO
Inventors: John P. Biggie; Timothy J. Galus
Original assignee: Api Heat Transfer, Inc.
Priority date: 2007-08-30
Filing date: 2007-08-30
Publication date: 2009-03-05

Abstract

A plate and ring type heat exchanger (10) and method of manufacture thereof whereby the manifolds are built simultaneously with the cor to obviate the need of welding the manifolds onto the core after furnace brazing. Spacer elements (30) having a pair of spacer parts locateD at the fist and second manifolds (14A, 14B) and a pair of straight lengths extending along the core between the manifold spacer parts may be made in any length to allow for quick and easy changeover between the building of different width cores.

Description

BRAZED ALUMINUM PLATE AND RINGHEAT EXCHANGER

AND METHOD OF MANUFACTURE THEREOF FIELD OF THE INVENTION

The present invention relates to heat exchangers, and more particularly relates to brazed aluminum plate and ring type heat exchangers.

BACKGROUND OF THE INVENTION The conventional process for manufacturing brazed aluminum bar and plate type heat exchangers involves first building the main core for the heat exchanger through stacking of parts until the desired size of core is achieved. The parts are bound and placed in a furnace for melting of the braze alloy and securing of the adjoining parts together. A pair of manifolds are then welded to the opposite sides of the core. This process is time consuming and labor intensive.

There is thus a need for a method of manufacturing a heat exchanger which reduces the manufacturing time and labor and particularly the time it takes to weld manifolds to the core.

SUMMARY OF THE INVENTION

The present invention successfully addresses the above need by providing a novel heat exchanger and method of manufacturing a heat exchanger which uses a spacer element and manifold parts that may be built simultaneously with the building of the core. As such, subsequent attachment of the manifolds to the core as was prior art practice is no longer necessary. Furthermore, the spacer elements may be easily and quickly made of different lengths along the width of the core to allow for quick and inexpensive changeover to different core widths.

More particularly, elongated spacer elements are positioned to surround a respective inside fin through which fluid is directed from one manifold to the manifold on the opposite side of the core. Manifold parts, e.g., in the shape of a hollow ring, are brazed to the opposite ends of the spacer element which extend beyond either end of the inside fin. The spacer elements and manifold parts are stacked in alternating relationship to the desired height of the heat exchanger with a single vertical stack comprising a continuous manifold. Solid end plates may be inserted at desired locations along a vertical stack to create separate fluid cooling circuits as desired.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become apparent and be better understood by reference to the following description of an embodiment of the invention in conjunction with the accompanying drawings, wherein:

Fig. 1 is a front elevational view of an embodiment of the invention; Fig. 2 is a perspective view thereof;

Figure 3 is a cross-sectional view thereof as taken generally along the line 3-3 of Fig. 2;

Figure 4 is a perspective, exploded view thereof; Figure 5 is a cross-sectional, elevational view of a part of the assembly to show the air flow circuit through the core and manifolds;

Figure 6 is an enlarged, perspective view of an external fin;

Figure 7 is an enlarged, perspective view of an internal fin;

Figure 8a is a cross-sectional view as taken generally along the line 9a-9a in Fig. l; and

Figure 8b is a plan view of a spacer element with the end and side pieces thereof shown in spaced relation.

Corresponding reference characters indicate corresponding parts throughout the several views. The examples set out herein illustrate a preferred embodiment of the invention and such exemplification is not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION

Referring now to the Figures, there is shown one possible embodiment of the present invention comprising a heat exchanger 10. Heat exchanger 10 generally includes a core 12 and manifolds 14a,b and 16a,b located on opposite sides of core 12. In this particular embodiment, heat exchanger 10 includes two fluid circuits which are physically separated by solid plates 18, 20 positioned between manifolds 14a,b and 16a,b, respectively. Thus, a first fluid circuit is defined with fluid entering manifold 16a at inlet port IN₁ and exiting manifold 14a at outlet port OUT₁, and a second fluid circuit is defined with fluid entering manifold 16b at inlet IN₂ and exiting manifold 14b at outlet OUT₂. As stated above, prior practice for constructing brazed aluminum bar and plate type heat exchangers involved building the core through a stacking of parts which was then bound for processing in a furnace. Once removed from the furnace, the manifolds were welded onto the core. In the present invention, the manifolds and cores are constructed at the same time as described below. To begin constructing heat exchanger 10, a worker lays a side plate 22

(sometimes also referred to as head, bottom, top or end plate depending on the desired orientation reference) on a work surface or other support. A sheet of braze material 24 which is clad on both surfaces thereof with a braze alloy is then laid upon the side plate 22. The braze sheet 24 extends beyond either end of the side plate and includes openings 24a,b to allow fluid to pass therethrough, respectively. An external fin 26 of about the same length as side plate 22 is laid upon braze sheet 24. A pair of end plates 28a,b having respective openings 28a',28b' are then positioned on the exposed ends of braze sheet 24 adjacent to and substantially flush with either end of the external fin 26. Openings 28a', 28b' are positioned to align with openings 24a, 24b in braze sheet 24, respectively. When making alternate heat exchanger embodiments, one or more of the end plates may be made solid with no through-hole to close a fluid path as is well understood by those skilled in the art of heat exchanger design. A second braze sheet 24₂ is placed upon external fin 26 and end plates 28a, 28b, braze sheet 24₂ also including a pair of openings 24a, 24b which align with openings 28a', 28b', respectively. An elongated spacer element 30 is provided to lay upon and substantially follow the outline of braze sheet 24₂ . One or more internal fins 32a, 32b are positioned upon braze sheet 24_{2 1} inside the perimeter of spacer element 30. Along the core 12 of exchanger 10, spacer elements 30 form a closed wall about the internal fins 32a, 32b. Although a pair of internal fins 32a,32b are placed in side-by-side relationship, it is understood that any number of internal fins may be used to form a single layer of internal fin in the core. Whether a single internal fin is used or more than one is used depends on the width of the core being built and the standard lengths of fin available at the time of the build. If the core width is larger than the standard length of fin, then more than one fin will be needed to extend across the desired core width.

Once the internal fins are placed, another braze sheet 24₃ is placed upon the internal fins and spacer element 30 including opposite ends 30a,30b thereof. Holes 24₃a and 24₃ b formed in braze sheet 24₃ align with holes 24a, 24b in the previously laid braze sheet 24₂ to accommodate the manifold openings 14a, 14b, respectively. A pair of manifold rings 40a, 40b are positioned to encircle the holes 24₃a and 24₃ b formed in braze sheet 24₃ which are positioned directly over either end 30a, 30b of the spacer element, respectively. The inside diameter of the manifold rings preferably substantially match the inside diameter of the spacer element and holes 24₃a and 24₃ b at their juncture. Of course the spacer element 30 does not completely encircle the manifold ring or holes 24₃a and 24₃ b but rather straightens as it extends toward its opposing end. This creates a fluid gap between adjacent manifold rings in the stack wherethrough fluid may pass between the internal fin in the core and the manifolds formed by the rings, braze sheets and spacer elements. This is seen best by the arrows in Fig. 5 where fluid is seen entering manifold section 16a, passing through spacer element ends 30b and manifold ring 40b and passing into internal fins 32a, 32b, continuing toward opposite manifold section 14a and out through spacer element 30a and manifold ring 40a. Figure 5 thus illustrates the basic building unit of heat exchanger 10 which may be repeated in the layered fashion shown in Fig. 4 until a heat exchanger of the desired height is achieved.

Thus, the stacking of the braze sheets, spacer elements, manifold rings and internal and external fins is continued in the manner explained above until the desired height of the exchanger being built is reached. In the exchanger embodiment of the Figures, a second fluid circuit is created by replacing manifold rings with solid end plates 18, 20 at a desired location along the manifold to close the fluid path and create separate manifold sections. Of course any number of fluid circuits for the same or different fluids to be cooled in the same heat exchanger can be built in this manner as desired.

The assembled heat exchanger is compressed and banded prior to being placed in the braze furnace. The brazing operation is carried out in the usual manner such that the braze alloy melts and re-solidifies producing an integral assembly capable of handling pressure in the manifolds and internal passages. Since the manifolds are an integral part of the brazed assembly, the fit-up and welding of manifolds to a core as in prior practice is eliminated.

While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims.

Claims

What Is Claimed Is:

1. A method of making a heat exchanger comprising the steps of: a. positioning a side plate on a work surface; b. placing a first braze sheet having braze alloy on either surface thereof over said side plate; c. placing an external fin over said first braze sheet; d. said external fin being shorter in length than said first braze sheet such that said first braze sheet extends beyond the length of said external fin at both ends thereof; e. placing first and second end plates on the exposed ends of said first braze sheet; f. placing a second braze sheet having braze alloy on either surface thereof on said external fin and said end plates; g. placing an elongated spacer element on said second braze sheet said spacer element extending along the entire perimeter of said second braze sheet; h. placing an internal fin on said second braze sheet inside the perimeter of said spacer element; i. placing a third braze sheet having braze alloy on either surface thereof over said internal fin and spacer element; j. placing first and second manifold parts forming first and second manifolds on said third braze sheet over said spacer element at opposite ends of said internal fin, said manifold parts having a portion thereof not seated upon said spacer element; and k. repeating steps b - j until the heat exchanger is of the desired height.

2. The method of claim 1, and further comprising the step of processing said heat exchanger in a furnace to melt the braze alloy and thereby secure the parts of the heat exchanger together.

3. The method of claim 1 , and further comprising the steps of creating separate fluid circuits by replacing one or more manifold parts with a solid end plate.

4. The method of claim 1 , wherein vertically stacked manifold parts are in fluid communication.

5. The method of claim 1 wherein an an outlet port is formed at said side plate at said first manifold and an inlet port is formed at said side plate at said second manifold.

6. The method of claim 1 wherein said manifold parts are circular.

7. The method of claim 1 wherein said spacer element is a continuous piece.

8. The method of claim 1 wherein said spacer element is formed in multiple pieces.

9. The method of claim 8 wherein said spacer element is formed of both straight pieces and curved pieces.

10. The method of claim 9 wherein said curved pieces are positioned at opposite ends of said braze sheet and said manifold parts are positioned on said curved pieces, respectively.

11. A plate and ring type heat exchanger building unit comprising a spacer element, first, second, third and fourth manifold parts, an internal fin and an external fin wherein said spacer element is positioned over said first and second manifold parts and said internal fin is positioned within the perimeter of said spacer element, and said third and fourth manifold parts positioned over said spacer element and aligned with said first and second manifold parts, respectively, such that a fluid path is created between said manifold parts and said internal fin.

12. The heat exchanger of claim 11 wherein multiple heat exchanger building units may be placed in stacked relationship until the desired height of heat exchanger is reached.

13. The heat exchanger of claim 11 wherein said spacer element includes opposite end parts and first and second side parts which are placed together to form a continuous perimeter when building said heat exchanger.

14. The heat exchanger of claim 13 wherein the heat exchanger has a core comprised of said internal and external fins and said spacer elements, and whereby said side parts may be formed of varying lengths to form heat exchanger cores of respectively varying widths.

15. The heat exchanger of claim 11 wherein braze sheets having braze alloy on each surface thereof are placed between said external fin, said spacer element, said internal fin and said manifold parts whereby said braze alloy may be melted in a braze furnace to secure these parts to the adjacent braze sheet surface.