Manifold bending support and method for using same

The subject invention relates generally to a manifold bending support; more particularly to a bending support adapted to be inserted into a manifold header of a heat exchanger to prevent the manifold header from collapsing during the bending of the manifold; and a method for using the bending support for manufacturing a heat exchanger having at least one bent manifold.

Due to their high heat transfer efficiency, automotive style brazed heat exchangers have been modified for residential and commercial air conditioning and heat pump applications. A typical modified automotive heat exchanger includes a pair of manifold headers having a plurality of flat tubes in hydraulic connection therebetween for refrigerant flow from one manifold header to the other. Having uniform refrigerant distribution through the plurality of flat tubes is important for optimal heat transfer. To provide for uniform refrigerant distribution through the core of flat tubes, larger diameter manifold headers are used in conjunction with internal refrigerant distribution and collection conduits in the inlet and outlet manifold headers, respectively.

In order to meet packaging constraints for residential and commercial applications, the larger diameter manifold headers of the modified automotive heat exchanger may be bent about an axis on a mandrel. With larger diameter manifold headers, the bending process has a tendency to deform the wall of the manifold header into a substantially egg-shaped cross sectional profile.

It is desirable to have a bending support adapted for use in the bending of a manifold header of a heat exchanger, in which the bending support prevents stress concentrations from deforming the inner radius of the bend. It is further desirable to have a bending support adapted to hold and maintain the internal refrigerant conduit in a predetermined position within the manifold header during the bending process and which assists in the bending of the internal refrigerant conduit to conform to the bend contour of the manifold. It is still further desirable for a method of using the bending support in the manufacturing of a heat exchanger having a bent manifold header that includes an internal refrigerant conduit conforming to the bent contour of the manifold.

An embodiment of the present invention provides a bending support adapted to be inserted into a manifold header that has an internal refrigerant conduit of a heat exchanger assembly and a method of using the bending support in the manufacturing of the heat exchanger assembly.

The bending support includes a substantially planar bracing member with a length (L) that is substantially equal to that of the inner diameter (I.D.) of the manifold header that the bending support is ultimately inserted in. Extending from a surface of the bracing member is a pair of bracketing members that are spaced apart at a distance substantially equal that of the outer diameter (O.D.) of the refrigerant conduit. The pair of bracketing member and the portion of the planar bracing member therebetween define a refrigerant conduit clip. The interior surface of the refrigerant conduit clip includes a skived pattern defining a plurality of teeth or protrusions that aids in the engagement of the refrigerant conduit clip onto the internal refrigerant conduit. An aperture located on the planar bracing member provides an unobstructed refrigerant pathway for refrigerant flow to or from the internal refrigerant conduit.

A plurality of the bending supports are oriented and clipped onto the refrigerant conduit at predetermined locations prior to the refrigerant conduit being inserted into the manifold header. A first bending support is clipped onto the center or apex A of the desired bend, a second and third bending supports are clipped onto either end of the bend as it transitions into a straight run. The header manifold is oriented toward a mandrel where the bracing member of the bending support is substantially perpendicular to the work surface of the mandrel. The bending support substantially maintains the inner diameter of the manifold header to prevent the manifold header from being crushed. Also, the bending support serves to maintain the refrigerant conduit in its desired position during the bending process.

Accordingly, the bending support maintains the diameter of the manifold header during the bending process to prevent the inner radius wall from collapsing or deforming. The bending support also holds and maintains the internal refrigerant conduit in a predetermined position during the bending process to conform to the bend contour of the manifold header, thereby preventing the refrigerant conduit from deforming.

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 shows a perspective view of one embodiment of the bending support.

FIG. 2 shows a cross-sectional end view of a manifold header having a bending support maintaining a refrigerant conduit in a predetermined position.

FIG. 3 shows a perspective view of a plurality bending supports being assembled onto the refrigerant conduit prior to the insertion of the refrigerant conduit assembly into the manifold header.

FIG. 4 shows a partial cut-away perspective view of a manifold header having a bending support engaged to the refrigerant conduit.

FIG. 5A shows a cross-sectional view of the manifold header having multiple bending supports engaged to the refrigerant conduit.

FIG. 5B shows a cross-sectional view of the manifold header of FIG. 5A bent at a 90 degree angle about an X-axis.

FIG. 6A shows a cut-away perspective view of the manifold header having the bending support properly positioned on a mandrel.

FIG. 6B shows the cut-away perspective view of the manifold header of FIG. 6A being bent about the X-axis on the mandrel.

This invention will be further described with reference to the accompanying drawings, wherein like numerals indicate corresponding parts throughout the views. The modified automotive heat exchanger represented in the drawings generally includes a first manifold header 14 having a substantially round cross-sectional area, a second manifold (not shown) spaced apart from the first manifold header 14 , an internal refrigerant distribution or collection conduit 20 extending within one or both of the manifold headers, and a plurality of flat tubes 44 interconnecting the first 14 and second manifold headers for refrigerant flow from one manifold header to the other. The modified automotive heat exchanger shown is for illustrative purposes and represents one of many exemplary embodiment of the invention; therefore, the modified automotive heat exchanger shown should not be considered as a limiting example. In the following description of the bending support 12 and the method of using the bending support 12 , the modified automotive heat exchanger will be generically referred to as a heat exchanger assembly 10 .

Shown in FIGS. 1-6B is a bending support 12 adapted to be inserted into a manifold header 14 of a heat exchanger assembly 10 . The bending support 12 has features that enable it to support the inner radius wall 16 , best shown in FIG. 5B , of the manifold header 14 during the bending process to prevent the inner radius wall 16 from forming an egg-shaped cross sectional profile. The bending support 12 also has features that hold and maintain the internal refrigerant conduit 20 in a predetermined position during the bending process to conform to the bend contour of the manifold header 14 , thereby preventing the refrigerant conduit 20 from deforming. The details and advantages of these features will be clearer with the description that follows.

FIGS. 1 and 2 show a bending support 12 having a substantially planar bracing member 22 . The bracing member 22 has a length (L) that is substantially equal to that of the inner diameter (I.D.) of the manifold header 14 that the bending support 12 is ultimately inserted in. The bracing member 22 includes two opposing bracing member edges 24 and a bracing member surface 26 .

Extending substantially perpendicularly from the bracing member surface 26 is a pair of bracketing members 28 . Each of the two bracketing members 28 includes a bracketing member interior surface 34 and a bracketing member distal end 30 . The pair of bracketing members 28 together with a portion of the bracing member 22 therebetween define a refrigerant conduit clip 32 . The pair of bracketing members 28 is spaced at a distance substantially equal that of the outer diameter (O.D.) of the refrigerant conduit 20 that the bending support 12 ultimately engages and includes an interior bracketing member surface 34 having a skived pattern 36 defining a plurality of teeth or protrusions 36 . The portion of the bracing member 22 between the pair of bracketing members 28 defines an aperture 38 .

FIG. 2 shows the bending support 12 inserted into the interior of the header manifold 14 . The bending support 12 is sized such that the opposing bracing member edges 24 and the bracketing member distal ends 30 abut the interior surface 40 of manifold header 14 . It is preferable that the bracing member 22 extends across the inner diameter of the manifold header 14 . To ensure a secure fit, the length (L) of the bracing member 22 may be sized slightly longer than the inner diameter (I.D.) of the manifold header 14 to form an interference fit. To maximize the contact area to ensure a tight fit, the bracketing member distal ends 30 and bracing member edges 24 may be contoured to conform to the curvature of the interior surface 20 of the manifold header 14 . The bending support 12 may be fabricated as a continuous aluminum extrusion and then cut to the desired length.

FIG. 3 shows a plurality of bending supports 12 being clipped onto the refrigerant conduit 20 prior to the insertion of the refrigerant conduit 20 into the interior of the manifold header 14 . Each bending support 12 is pre-oriented and clipped onto a strategic predetermined location along the refrigerant conduit 20 as described in the following.

Prior to the insertion of the refrigerant conduit 20 into the manifold header 14 , the bend apex of the refrigerant conduit 20 corresponding to the desired bend apex (A) of the manifold header 14 is identified. A first bending support 12 A, a second bending support 12 B, and a third bending support 12 C are provided. With reference to FIGS. 3 , 5 A, and 5 B, the first bending support 12 A is clipped onto the refrigerant conduit 20 at or about the portion of the refrigerant conduit 20 corresponding to the desired bend apex (A) of the manifold header 14 . The first bending support 12 A is oriented in a direction in which one of the bracing member edges 24 is directed toward the X-axis, the axis about which the manifold header 14 is bent and the length (L) of the bracing member 22 extends radially from the X-axis. The second and third bending supports 12 B, 12 C are clipped onto the refrigerant conduit 20 at or about the portions that correspond to the bend transitions (T) of the manifold header 14 . The second and third bending supports 12 B, 12 C are oriented in the same direction as that of the first bending support 12 A, in which one of the bracing member edges 24 is directed toward the X-axis.

Shown in FIG. 4 is a partial cut-away perspective view of the manifold header 14 having a bending support 12 clipped onto the refrigerant conduit 20 . The manifold header 14 shown includes a plurality of slots 42 for the insertion of flat tubes 44 . In this exemplary embodiment, the aperture 38 of the bending support is aligned with the refrigerant distribution or collection ports 46 of the refrigerant conduit 20 for unrestricted refrigerant flow to or from the refrigerant conduit 20 . However, it is not necessary for the aperture 38 to be directly aligned with the ports 46 of the refrigerant conduit 20 .

Shown in FIG. 5A , three bending supports 12 A, 12 B, 12 C are clipped onto the refrigerant conduit 20 and the assembly is inserted into the manifold header 14 . At this stage of the assembly, manifold caps 48 may be placed on either end of the manifold header 14 , one end of the flat tubes 44 inserted into the corresponding tube slots 42 , and the other end of the flat tubes 44 may be inserted into the corresponding tube slots of the other manifold header (not shown) forming the heat exchanger assembly 10 . The assembly may be brazed into a solid integral heat exchanger assembly 10 . After brazing, the manifold headers 14 may be bent on a mandrel to conform the heat exchanger assembly 10 to the desired packaging requirement. Alternatively, the headers manifold 14 with the inserted refrigerant conduits 20 and bending supports 12 may be individually bent prior to the assembly and brazing of the remaining components of the heat exchanger assembly.

Shown in FIG. 5B , is cross sectional view of a bent manifold header 14 forming a right angle along with the relative location of the three bending supports 12 A, 12 B, and 12 C. The first bending support 12 A is located at the center or apex A of the bend; the second and third bending support 12 B, 12 C are located at either end of the bend as it transitions into a straight run.

Shown in FIG. 6A is a heat exchanger assembly 10 having the header manifold 14 positioned onto a mandrel 50 . The header manifold 14 is oriented where the bracing member 22 of the bending support 12 is substantially perpendicular to the work surface of the mandrel. As a force is applied causing the header manifold 14 to bend onto the work surface and about the X-axis, a portion of the force is transmitted to the refrigerant conduit 20 via the bending support 12 assisting in the bending of the refrigerant conduit 20 to a curvature that closely conforms to the bend curvature of the manifold header 14 ; thereby preventing any pinch points from forming in the refrigerant conduit 20 . The bending support 12 also aids in maintaining the desired position of the refrigerant conduit 20 relative to the manifold header 14 during the bending process.

The bending support 12 supports the inner radius of the manifold header 14 during the bending process, thereby providing the advantage of preventing stress concentrations from deforming the inner radius of the bend. The bending support 12 maintains the internal refrigerant conduit 20 in a predetermined position during the bending process to conform the bend of the refrigerant conduit 20 to the bend of the manifold header 14 , thereby providing the advantage of preventing crimps in the refrigerant conduit 20 .

While the invention has been described with reference to an exemplary embodiment, 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 essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.