Patent Grant
8267160
Not Applicable.
Not Applicable.
Conventional air conditioning systems generally comprise a compressor, a condenser coil, a condenser fan for passing air through the condenser coil, a flow restriction device, an evaporator coil, and an evaporator blower for passing air through the evaporator coil. The condenser coil and the evaporator coil are each designed as heat exchangers with internal tubing for carrying refrigerant. Further, evaporator coils and condenser coils sometimes comprise a plurality of fins disposed along a length of the internal tubing so that the internal tubing passes through holes formed in the adjacent plate fins.
The compressor operates to compress refrigerant into a hot and high pressure gas, which is passed through the internal tubing of the condenser coil. As the refrigerant is passed through the condenser coil, the condenser fan operates to pass ambient air across the condenser coil, thereby removing heat from the refrigerant and condensing the refrigerant into liquid form. The liquid refrigerant passes through a flow restriction device, which causes the refrigerant to transform into a colder and lower pressure liquid/gas mixture that proceeds to the evaporator. As the mixture is passed through the evaporator coil, the evaporator blower forces ambient air across the evaporator coil, thereby providing a cooling and dehumidifying effect to the ambient air, which is then distributed to the space to be temperature controlled.
In some applications, heat exchangers (i.e., evaporator or condenser coils) comprise a plurality of fins that are arranged so that adjacent fins are substantially parallel to each other and offset by a fin pitch distance, and a plurality of refrigerant tubes disposed generally orthogonally to the plurality of fins. Most generally, a fin may be described as a thin plate constructed of metal or other materials suitable for conducting heat and comprising a series of holes formed therein that are suitable for receiving refrigerant tubing therethrough. A plurality of fins comprising substantially similar hole patterns may be arranged in a stack, in some embodiments with adjacent fins equally offset by the fin pitch distance, so that refrigerant tubes may each be received through corresponding holes in the plurality of fins. In other words, each refrigerant tube may be inserted substantially orthogonally through corresponding holes in the stack of fins so that the fins are disposed along the refrigerant tubing, thereby forming what may be referred to as a slab of the heat exchanger.
In some embodiments, this disclosure relates to a fin comprising a substantially flat base plane having a first side facing a first direction and a second side facing a second direction. The fin further comprises a first louver comprising a leading edge and a trailing edge, wherein the leading edge is closer to the base plane than the trailing edge and the trailing edge is offset from the base plane in the first direction; a second louver located at least partially downstream of the first louver, the second louver comprising a leading edge and a trailing edge, wherein the leading edge is offset from the base plane in the second direction and the trailing edge is offset from the base plane in the first direction; and a third louver located at least partially downstream of the second louver, the third louver comprising a leading edge and a trailing edge, wherein the leading edge is offset from the base plane in the second direction and the trailing edge is closer to the base plane than the leading edge.
In some embodiments, the present disclosure relates to a fin comprising a substantially flat base plane having a first side facing a first direction and a second side facing a second direction. The fin further comprises a central louver comprising a leading edge and a trailing edge, wherein the leading edge and the trailing edge are offset from the base plane in the same one of the first direction and the second direction; and a nearest located louver located nearest the central louver, the nearest located louver comprising a nearest located edge located nearest the central louver, wherein the nearest located edge is nearer the base plane than any portion of the central louver.
In some embodiments the present disclosure relates to a fin comprising a substantially flat base plane having a first side facing a first direction and a second side facing a second direction. The fin further comprises a first louver comprising a leading edge and a trailing edge, wherein the leading edge is closer to the base plane than the trailing edge, the trailing edge is offset from the base plane in the first direction, and the first louver is formed into a concave curve open toward the first direction; a second louver located at least partially downstream of the first louver, the second louver comprising a leading edge and a trailing edge, wherein the leading edge is offset from the base plane in the second direction, the trailing edge is offset from the base plane in the first direction, and is substantially flat; a third louver located at least partially downstream of the second louver, the third louver comprising a leading edge and a trailing edge, wherein the leading edge is offset from the base plane in the second direction, the trailing edge is closer to the base plane than the leading edge, and the third louver is formed into a concave curve open toward the second direction; a fourth louver located at least partially downstream of the third louver, the fourth louver comprising a leading edge and a trailing edge, wherein both the leading edge and the trailing edge are offset in the first direction, and wherein the fourth louver is substantially flat; a fifth louver located at least partially downstream of the fourth louver, the fifth louver comprising a leading edge and a trailing edge, wherein the trailing edge is offset from the base plane in the second direction, the leading edge is closer to the base plane than the trailing edge, and wherein the fourth louver is formed into a concave curve open toward the second direction; a sixth louver located at least partially downstream of the fifth louver, the sixth louver comprising a leading edge and a trailing edge, wherein the leading edge is offset from the base plane in the first direction, the trailing edge is offset from the base plane in the second direction, and wherein the sixth louver is substantially flat; and a seventh louver located at least partially downstream of the sixth louver, the seventh louver comprising a leading edge and a trailing edge, wherein the trailing edge is closer to the base plane than the leading edge, the leading edge is offset from the base plane in the first direction, and wherein the seventh louver is formed into a concave curve open toward the first direction.
For a more detailed description of the various embodiments disclosed herein, reference will now be made to the accompanying drawings, wherein:
Some fins of heat exchangers comprise forms and features that increase heat transfer between the fins and the airflow passing over the fins. For example, fins may be constructed of relatively inexpensive and flexible flat finstock which may be easily lanced (cut and offset) or louvered (cut and twist) through well known manufacturing processes using dies and presses to improve heat transfer performance. However, some fins may be constructed by forming a wavy finstock from relatively thicker and more expensive flat finstock. Wavy finstock demonstrates good heat transfer performance with less pressure drop than lanced and/or louvered flat finstock. To further improve heat transfer performance, lanced and/or louvered features may also be formed on the wavy finstock. While some features formed on a wavy finstock in combination with the wavy or curved nature of the wavy finstock may offer improved heat transfer, the dies needed to form the fins from wavy finstock are more complex and more expensive. Because the flat finstock used to form the wavy finstock is thicker and more expensive than the thinner finstock that may be used when the finstock need not be pressed into a wavy form, use of wavy finstock is sometimes avoided due to cost considerations.
The present disclosure is directed to flat fins and methods of making the flat fins with features that provide the heat transfer and low pressure drop performance of some lanced and/or louvered wavy fins. Accordingly, the present disclosure provides fins formed from flat finstock and methods of making fins formed from flat finstock that comprise louvers that direct airflow in a manner substantially the same as some louvered wavy fins. In this disclosure, the terms “upstream” and “downstream” are intended to indicate relative positions as related to the general intended overall direction of airflow across a fin of the present disclosure. Accordingly, for example, where a feature of a fin of this disclosure is described as being upstream relative to another feature of the fin, the upstream feature of the fin can be understood as being generally disposed so that the upstream feature encounters a portion of airflow prior to the relative downstream feature encountering the same portion of airflow. Further, it will be understood that the term “leading” may also refer to a relatively upstream located feature. Similarly, it will be understood that the term “trailing” may also refer to a relatively downstream located feature. Such relative positional terminology is well known in the art of heat exchanger fins.
Referring now to
It will be appreciated that the base regions 104 are substantially formed from unbent flat finstock while the plurality of louvers, described in detail below, are formed by cutting, displacing, and twisting the same flat finstock. The bluff bodies 108 are generally formed by pressing the flat finstock. In this embodiment, each finstrip 102 further comprises an upstream louver 110, an upstream straight louver 112, an upstream curved louver 114, a central louver 116, a downstream curved louver 118, a downstream straight louver 120, and a downstream louver 122. Further, each finstrip 102 of a fin 100 may be described as having a base plane 124 from which the louvers 110, 112, 114, 116, 118, 120, 122 are originally part of and subsequently bent or otherwise deformed away from during their creation. In some embodiments, the base regions 104 remain substantially coplanar with the base plane 124.
Referring now also to
A bisection plane 126 is substantially orthogonal to the base plane 124 and substantially bisects the finstrip 102 along its length. In this embodiment, it will be appreciated that the pairs of cross-sectional areas of louvers, 110 and 122, 112 and 120, and 114 and 118, are substantially mirror images of each other about the bisection plane 126. The downstream curved louver 118 is located just downstream of the central louver 116 and extends from its leading edge that is substantially coplanar with the base plane 124 and curves downwardly away from the base plane 124 in a generally concave manner so that the concavity is open away from and below the base plane 124. The downstream straight louver 120 is located just downstream from the downstream curved louver 118 and extends downstream from its leading edge that is above the base plane 124, through the base plane 124, and in a manner so that its trailing edge is located below the base plane 124. The downstream straight louver 120 is substantially planar, straight, flat, and/or linear between its leading edge and its trailing edge. In this embodiment, both of the leading edge and the trailing edge of the downstream straight louver 120 are located substantially equidistant from the base plane 124. Downstream louver 122 comprises a cross-sectional area that extends downstream from its leading edge that is above the base plane 124 and gradually curves in a generally concave manner toward the base plane 124 so that the trailing edge of the downstream louver 122 is substantially coplanar with the base plane 124.
As shown in the drawings, in some embodiments such as those shown at least in
Referring again to
Referring now to
Still referring to
Further, it will be appreciated that the louvers 110, 112, 114, 116, 118, 120, 122 may be provided in alternative embodiments with different relative sizes, different curvatures, and/or in different numbers of louvers on a finstrip 102. Nonetheless, the alternative embodiments of louvers may still provide the above-mentioned mixing of airflows, dividing or bisecting of airflows, and guiding of airflows along a generally wavy path. Further, in alternative embodiments, rather than locating adjacent louvers of the same finstrip 102 so that airflows are bisected, the adjacent louvers may be located so that the leading edges of subsequent downstream located louvers are offset from the trailing edges of the nearest upstream louvers by at least about 25% of the fin pitch distance of a heat exchanger. In other words, in some embodiments, an airflow may be divided into unequal portions as it exits an airflow space. Still further, the overall dimensions of louvers of the various embodiments disclosed may be chosen to minimize the occurrence of trapping water between the louvers and adjacent structures of the fins.
At least one embodiment is disclosed and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, R1, and an upper limit, Ru, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=R1+k*(Ru−R1), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention. The discussion of a reference in the disclosure is not an admission that it is prior art, especially any reference that has a publication date after the priority date of this application. The disclosure of all patents, patent applications, and publications cited in the disclosure are hereby incorporated by reference in their entireties.
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