Heat exchangers are used to transfer thermal energy from one stream of fluid at a first, higher temperature to another stream of fluid at a second, lower temperature. Oftentimes such heat exchangers are used to remove waste heat from a process fluid such as oil, coolant, or the like by transferring that heat to a flow of cooler air directed to pass through the heat exchanger.
In certain applications, the process fluid to be cooled is also at an operating pressure that is substantially greater than the ambient atmospheric pressure of the heat exchanger's surroundings. As a result, it becomes necessary for the heat exchanger to be designed to withstand the pressure forces that result from the process fluid passing through the heat exchanger. This can become challenging, especially in cases where the heat exchanger is to be used in large systems and machinery such as, for example, construction equipment, agricultural machines, and the like. As the size of the machine or system increases, the flow rate of the process fluid also increases, necessitating larger heat exchangers to accommodate both the heat transfer requirements and the fluid flow rates.
In some particular styles of heat exchangers, the fluid to be cooled is directed through an array of flat tubes extending between two tanks or headers. As such heat exchangers become larger, they can have substantially large surface areas exposed to the pressure of the process fluid, especially in the tank or header areas, and the force of the fluid pressure acting on these large surfaces can lead to destructive mechanical stresses in the heat exchanger structure. The ability to withstand such pressures can be improved through the use of circular header profiles, but circular headers can be difficult to package within a compact space as the required size of the heat exchanger increases.
According to an embodiment of the invention, a header for a heat exchanger includes a first and a second cylindrical fluid manifold extending in parallel. Each of the first and second manifolds have tube slots that extend through an arcuate wall section of the manifold. A thickened wall section of the header having a generally triangular wall section is bounded by the first and second fluid manifolds and by a planar outer surface of the header. An aperture extends through the thickened wall section to provide a fluid communication pathway between the first and second cylindrical fluid manifolds.
In some embodiments, the header includes a plug that is inserted into an opening that extends through the planar outer surface to the aperture. In some such embodiments the plug is brazed to the planar outer surface. In some embodiments the plug includes an integral mounting pin that extends outwardly from the header in a direction perpendicular to the planar outer surface. In some embodiments the arcuate wall section of one of the manifolds defines a minimum wall thickness of the header, and the insertion depth of the plug through the opening is approximately equal to that minimum wall thickness.
In some embodiments the header includes a third cylindrical fluid manifold adjacent to and parallel to the second fluid manifold. A second thickened wall section of the header having a generally triangular wall section is bounded by the third and second fluid manifolds and by the planar outer surface of the header. In some such embodiments an aperture extends through the second thickened wall section to provide a fluid communication pathway between the second and third fluid manifolds.
In some embodiments the header includes a first and a second mounting flange extending from the header. The first mounting flange defines a first mounting plane and the second mounting flange defines a second mounting plane, with both the first and second mounting planes being oriented parallel to one another and perpendicular to the planar outer surface of the header. A first mounting hole extends through the first mounting flange and is aligned with a second mounting hole that extends through the second mounting flange. In some such embodiments all of the fluid manifolds are entirely located between the first and second mounting planes.
According to another embodiment, a method of making a header for a heat exchanger includes providing an extruded section with two unconnected cylindrical volumes arranged therein and with a planar outer surface, and machining through the planar outer surface to define an aperture between the two cylindrical volumes. The act of machining through the planar outer surface creates an opening in that surface, and a plug is inserted into the opening. In some embodiments the plug is brazed to the extruded section in order to secure it within the opening. In some embodiments a series of tube slots are formed into arcuate wall sections of the two cylindrical volumes opposite the planar outer surface.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the accompanying drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
A heat exchanger 1 according to an embodiment of the invention is depicted in
Open ends of the tubes 5 are received into headers 3 arranged at opposing ends of the heat exchanger 1. Each header 3 is an assembly of parts, shown in exploded view in
As best seen in the cross-sectional view of
Tube slots 13 are provided along the lengths of the headers 3 to receive the ends of the tubes 5 into the corresponding cylindrical fluid manifolds 8. The tube slots 13 can be formed into the extruded section 7 by, for example, saw-cutting or piercing. Each of the tube slots 13 extends through one of the arcuate wall sections 9, and has a width and height that generally corresponds to the major and minor dimensions of the flat tubes 5. The ends of the flat tubes 5 are preferably inserted into the tube slots 13 after the flat tubes 5 and the fins 6 have been stacked to form the core 2, so that the tubes 5 can be brazed to the headers 3 in the same brazing operation as is used to join the flat tubes 5 to the fins 6, thereby creating leak-free joints at the tube-to-header interfaces.
The cylindrical fluid manifolds 8 are hydraulically connected by way of one or more apertures 15 that extend through the thickened wall section 21 at one or more locations along the length of the header 3. Such an aperture 15 can be formed by a machining operation such as drilling or milling through the planar surface 14 to a predetermined depth, in which case the forming of the aperture 15 can define a circular opening 40 in the planar surface 14, as shown in
A plug 12 can be inserted into the opening 40 defined by the forming of the aperture 15 at the planar outer surface 14 in order to provide a fluid-tight seal between the fluid manifolds 8 and the outside environment external to the header 3. The plug 12 includes an insertion portion 18 with a profile that generally matches the opening 40 created in the planar surface 14, so that the plug 12 can be partially inserted into that opening 40 with minimal clearance between side surfaces of the insertion portion 18 and the opening 40. A peripheral flange portion 17 extends beyond the outer periphery of the insertion portion 18 by an amount sufficient to engage and bear upon the planar surface 14 surrounding the opening 40, thereby limiting the insertion depth of the plug 12. In some especially preferable embodiments, such as the exemplary embodiment of
A groove 25 can be provided in the face of the peripheral flange portion 17 that is disposed against the planar surface 14, and can be used to accommodate a ring of braze material 16. The plug 12, along with the ring of braze material 16, can be assembled to the extruded section 7 prior to brazing of the heat exchanger 1, so that the plug 12 can be secured into the header 3 during the brazing operation. In some embodiments it may be more preferable to instead use a braze foil, braze paste, or clad braze layer on either the plug 12 or the extruded section 7, in which case the braze ring 16 and the groove 25 may be eliminated.
One or more of the plugs 12 can be provided with an integral mounting pin 19 extending outwardly away from the header in a direction perpendicular to the planar outer surface 14. The integral mounting pins 19 can be accommodated into corresponding holes of other components to which the heat exchanger 1 is to be assembled in order to, for example, secure the heat exchanger 1 within a cooling module. Annular vibration isolators can be conveniently assembled over the mounting pin 19 and bear against the peripheral flange portion 17 of the plug 12.
At the ends of the header 3, the cylindrical fluid conduits 8 are sealed with either end caps 11 or fluid ports 10. In the exemplary embodiment of
By placing multiple fluid manifolds 8 in hydraulic parallel, the present invention is able to provide a more robust design for applications wherein the fluid to be cooled is at an elevated pressure. The ability of the fluid manifold to withstand the elevated internal pressures imposed by the fluid is increased by reducing the diameter of each fluid manifold, without sacrificing the total flow area provided by the flat tubes 5. To that end, it should be understood that the number of cylindrical fluid manifolds 8 that may be provided in each of the headers 3 is not limited to two. Additional fluid manifolds 8 can be provided, and can be fluidly connected to adjacent fluid manifolds through additional apertures 15. It should be understood that a multi-pass heat exchanger can also be provided by placing apertures 15 between some, but not all, of the adjacent fluid manifolds 8.
As one non-limiting example of a heat exchanger having more than two cylindrical fluid manifolds within the headers, a portion of a heat exchanger 1′ is depicted in
The extruded section 7′, shown in greater detail in
The extruded header section 7′ can optionally be provided with mounting flanges 33, as shown in
The mounting flanges 33 can be used to structurally mount the heat exchanger 1′ into a cooling module or other assembly, as shown in
Various alternatives to the certain features and elements of the present invention are described with reference to specific embodiments of the present invention. With the exception of features, elements, and manners of operation that are mutually exclusive of or are inconsistent with each embodiment described above, it should be noted that the alternative features, elements, and manners of operation described with reference to one particular embodiment are applicable to the other embodiments.
The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention.
This application claims priority to U.S. Provisional Patent Application No. 62/353,618 filed Jun. 23, 2016, the entire contents of which are hereby incorporated by reference herein.
Filing Document | Filing Date | Country | Kind |
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PCT/US17/38480 | 6/21/2017 | WO | 00 |
Number | Date | Country | |
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62353618 | Jun 2016 | US |