1. Field of the Invention
The invention relates to manifolds having multiple chambers. More specifically, the invention relates to extruded manifolds with multiple chambers and cross-counterflow heat exchangers incorporating such manifolds.
2. Description of the Prior Art
Air-cooling (or heating) cross-counterflow heat exchangers are often used in applications where space limitations restrict the surface area of the heat exchanger. Cross-counterflow heat exchangers typically include a plurality of stacked, assembled modules, with each module including a pair of spaced manifolds interconnected by a plurality of spaced and parallel tubes. The modules are stacked such that air flows in a direction perpendicular to the face of the heat exchanger, and air fins are disposed between adjacent pairs of tubes for transferring heat from the tubes to the passing air.
Another type of cross-counterflow heat exchanger assembly is shown in U.S. Pat. No. 5,941,303, issued to James D. Gowan on Aug. 24, 1999 and hereinafter referred to as Gowan '303. Gowan '303 discloses a cross-counterflow heat exchanger comprising a pair of spaced and continually extruded manifolds. Each of the manifolds includes an interior, and each of the manifolds includes at least one dividing wall to divide the interior into a plurality of flow paths. A plurality of tubes extends and establishes fluid communication between the pair of manifolds. Each of the tubes includes at least one tube divider to separate it into a plurality of passages.
In summary, the invention provides a manifold having multiple chambers for use in a cross-counterflow heat exchanger assembly. The manifold includes a first member having arms extending from a base to arm ends. A second member is secured to the first member to define the manifold. The second member includes an inner plate edge that defines a first mating surface that extends inwardly along the inner plate edge from each of the plate ends to mate with arm ends. A wall extends transversely to the inner plate edge to a wall end. The wall end mates with an inner base surface to divide the interior of the manifold into a plurality of chambers. At least one lip extends transversely to the inner plate edge to define a second mating surface that extends perpendicularly from the first mating surface and mates with an inner arm surface of the arms.
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:
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, an exemplary heat exchanger assembly 20 is generally shown.
The exemplary heat exchanger assembly 20 includes a manifold 22 generally indicated having a first member 24 at least partially defining an interior. Referring to
Referring to
Referring to
The wall 46 includes at least one locking arm 96 that extends outwardly from the wall end 56 to mate with at least one opening 38. The locking arm 96 secures the second member 42 to the first member 24. The locking arm 96 is generally circular in cross section, but may be any shape known in the art.
The subject invention is distinguished by at least one lip 64 that extends transversely to the inner plate edge 50 to define a second mating surface 66, and thus creating a boot shape as seen in
Prior to brazing the first member 24 to the second member 42 to a cap 98 is disposed on each of the first and second manifold ends 68, 70 of the manifold 22. In addition to the clamping force F of the first member 24 on the second member 42, the cap 98 temporally secures the manifold 22 prior to being permanently secured.
The heat exchanger assembly 20 further includes a plurality of tubes 40 extending between first and second tube ends 74, 76. The first tube end 74 of each tube 40 is disposed in one of the first tube slots 36 of the manifold 22. Referring to
The assembly further includes a return manifold 84 extending in spaced and parallel relationship with the manifold 22. The return manifold 84 presents a plurality of second tube slots 86 longitudinally spaced from each other to correspond with the spacing of the first tube slots 36 of the manifold 22. The second tube end 76 of each tube 40 extends into and engages the corresponding second tube slot 86 to establish fluid communication between the tubes 40 and the return manifold 84. The return manifold 84 directs the flow of coolant from one of the passages of the tubes 40 to the other of the passages to define a two-pass cross-counterflow heat exchanger assembly 20. In an exemplary embodiment, the return manifold 84 is D-shaped to direct the flow of coolant from the one passages of the tubes 40 to the other passage of the passages, but the return manifold 84 may be any shape known in the art.
In the exemplary embodiment, the tubes 40 and the first and second tube slots 36, 86 each have a cross-section presenting parallel flat sides 88 that extend between round ends. However, the tubes 40 may be have any shape capable of transmitting a fluid between the first and second manifold 22. The flat sides 88 of adjacent tubes 40 are spaced from one another to define a plurality of air passages for the flow of air therebetween. A corrugated air fin 90 is disposed between and brazed to the parallel flat sides 88 of adjacent tubes 40 and extends between the first and return manifolds 22, 84 for dissipating heat from the tubes 40.
One of the chambers 58, 60 of the manifold 22 includes an input 92 in communication with an input chamber 58 for receiving a fluid, and an output 94 in communication with an output chamber 60 for dispensing the coolant after it has passed through the heat exchanger assembly 20. In an exemplary embodiment, the input 92 is disposed on the input chamber 58 that is downstream of the direction of the flow of air and the output 94 is disposed on the output chamber 60 upstream of the input chamber 58. The input 92 and output 94 may have any shape capable of delivering a fluid to the input chamber 58 and output chamber 60 of the manifold 22.
The embodiment shown in the drawings is for a two-pass counter cross-flow heat exchanger assembly. However, the manifolds and tubes may be designed to allow for more than two passes by inserting walls in either or both of the first and return manifolds and including a plurality of tube dividers in each tube. For example, in a three-pass heat exchanger assembly, the second member has one wall to divide the manifold into two chambers, the return manifold has one wall, and each tube has two tube dividers.
The invention also includes a method of forming a manifold 22 for use in a heat exchanger assembly 20. The method starts with the step of separately forming a first member 24 at least partially defining an interior and a second member 42. The first member 24 has a spaced set of first tube slots 36 and the second member 42 has a wall 46 that is positioned against the first tube slots 36 to divide the interior into a plurality of chambers 58, 60.
Next, the first member 24 is temporally secured to the second member 42. The arm ends 30 of the first member 24 are rolled to be canted toward one another. This creates a stress in the arms 26 of the first member 24 so that when the inner arm surface 32 of the first member 24 is brought into contact with the second mating surface 66 of the lip 64 of the second member 42, the first member 24 will be secured to the second member 42.
The method may further include the step of placing a cap 98 on each of the first and second manifold ends 68, 70. The shape of the cap 98 is contoured to mate with the outer periphery of the first and second manifold ends 68, 70. The cap 98 temporally secures the first member 24 to the second member 42 by the clamping force F.
The method continues with the step of permanently fixing the first member 24 to the second member 42 to define a manifold 22 after the temporally securing step. The second member 42 is preferably extruded and then cut to size, but may also be formed by other methods including casting and machining. In one embodiment, the forming the first member 24 is further defined as rolling a flat sheet of material into a channel having a cross-section presenting a U-shape and having a base 28 and arms 26 extending forwardly to arm ends 30. Rolling the first member 24 from a flat sheet provides advantages because the flat sheet can be a stock sheet of metal with a brazing material pre-disposed on either side of it. The brazing material then may be used for the step of permanently fixing the first member 24 to the second member 42.
The method proceeds with the step of forming a plurality of tubes 40 extending between first and second tube ends 74, 76. The method then continues with the step of forming a tube divider 78 extending between the first and second tube ends 74, 76 in each of the tubes 40 to separate each tube 40 into a first passage 80 and a second passage 82. Referring to
The method continues with the step of inserting the first tube end 74 of each tube 40 into one of the first tube slots 36 of the manifold 22 and abutting the divider of each tube 40 against the wall 46 of the second member 42 to establish fluid communication between the first passage 80 of the tubes 40 and one of the chambers 58, 60 of the manifold 22 and to establish fluid communication between the second passage 82 of the tubes 40 and the other of the chambers 58, 60 of the manifold 22. The first tube end 74 of each tube 40 is then permanently fixed to the associated first tube slot 36 manifold 22.
The method further continues with the step of forming a return manifold 84 having a set of second tube slots 86 being spaced from each other to correspond with the set of first tube slots 36 of the manifold 22. The method proceeds with the step of inserting the second tube end 76 of each of the tubes 40 into the corresponding second tube slot 86 of the return manifold 84 to establish fluid communication between the first and second passages 80, 82 of each tube 40 and the return manifold 84.
The method is finished with the steps of forming a plurality of air fins 90 and inserting one of the air fins 90 between adjacent tubes 40 to dissipate heat from the tubes 40. In the exemplary embodiment, the tubes 40, manifold 22, and air fins 90 are all brazed together to define a unified heat exchanger assembly 20.
The subject invention provides for a manifold and a cross-counterflow heat exchanger assembly 20 that is both cheaper and quicker to manufacture than those of the prior art. Additionally, the exemplary embodiment provides a more sturdy structure prior to and following brazing. Many of the traditional methods for forming the tube slots in the manifold of the Gowan '303 patent must be abandoned in order to avoid interfering with the dividing wall of the manifold. The first tube slots of the Gowan '303 patent must be milled or grinded, either of which is a very time consuming and costly process. The first tube slots 36 of the present invention may be formed in the first member 24 using a variety of manufacturing methods including stamping before the step of permanently fixing the first and second members 24, 42 together. This leads to significantly greater manufacturing efficiency, thereby reducing the cost and time to assemble the manifold 22 and of the heat exchanger assembly 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.