Lanced sine wave fin configuration for heat exchangers

Abstract

Described herein is a heat exchanger (100) comprising a plurality of plate fins (200). At least one plate fin (200) comprises a plurality of holes (204) arranged in one or more rows (202A, 202B), and a contoured region (302) formed adjacent to one of the plurality of holes (204) and having a sinusoidal corrugation (302). The contoured region (302) comprises a plurality of elongate adjustable lance elements (306; 306A-306C), wherein the sinusoidal corrugation (302) in each of the rows (202A, 202B) comprises three half-waves (W1-W3) of a first wave size in the middle portion (302-1) of the corresponding row (202A, 202B), and two half-waves (W4, W5) of a second wave size on lateral ends (302-2) of the corresponding row (202A, 202B), wherein the second wave size is smaller than the first wave size.

Description

BACKGROUND

[0001] This invention relates to the field of finned tube heat exchangers, and more particularly, a lanced sine-wave fin for heat exchangers.

[0002] US 5,111,876 A discloses a plate fin and tube heat exchanger configured to promote drainage of condensate that forms on the fin during heat exchanger operation. The fin is sinusoidally corrugated and has raised lance elements.SUMMARY

[0003] The present invention provides a heat exchanger comprising a plurality of plate fins. At least one plate fin comprises a plurality of holes arranged in one or more rows, and a contoured region formed adjacent to one of the plurality of holes and having a sinusoidal corrugation, the contoured region comprises a plurality of elongate adjustable lance elements; wherein the sinusoidal corrugation in each of the rows comprises three half-waves of a first wave size in a middle portion of the corresponding row, and two half-waves of a second wave size on lateral ends of the corresponding row, wherein the second wave size is smaller than the first wave size, wherein the sinusoidal corrugation comprises at least one peak and at least one valley, and wherein at least one elongate adjustable lance element among the plurality of elongate adjustable lance elements is formed at the at least one valley and / or the at least one peak.

[0004] Optionally, the plurality of elongate adjustable lance elements is offset relative to a central plane arranged at a midpoint of an amplitude of the sinusoidal corrugation.

[0005] Optionally, the plurality of elongate adjustable lance elements has a non-uniform lance width.

[0006] Optionally, the plurality of elongate adjustable lance elements has a non-uniform lance offset.

[0007] Optionally, width of the lance elements associated with the waves having the first wave size is greater than width of the lance element associated with the waves having the second wave size.

[0008] Optionally, amplitude of the lance elements associated with the waves having the first wave size is greater than amplitude of the lance element associated with the waves having the second wave size.

[0009] Optionally, an inter-row area between adjacent half-waves associated with the adjacent rows among the one or more rows has a planar profile.

[0010] Optionally, the sinusoidal corrugation comprises at least one peak and at least one valley, wherein at least one elongate adjustable lance element among the plurality of elongate adjustable lance elements is formed at a waveform between the at least one valley and the at least one peak.

[0011] Optionally, at least one elongate adjustable lance element among the plurality of elongate adjustable lance elements is offset such that a first gap created between a leading edge, upstream of airflow direction, of the corresponding lance elements and a surface of the plate fin is greater than a second gap created between a trailing edge, opposite to the leading edge, of the corresponding lance element and the surface of the plate fin.

[0012] Optionally, at least one elongate adjustable lance element among the plurality of elongate adjustable lance elements has a curved profile.

[0013] Optionally, at least one elongate adjustable lance element among the plurality of elongate adjustable lance elements has a flat profile.

[0014] Optionally, at least one elongate adjustable lance element among the plurality of elongate adjustable lance elements is inclined.

[0015] Optionally, the at least one elongate adjustable lance element is inclined such that a non-uniform gap is between a leading edge and a trailing edge of the corresponding lance element.

[0016] Optionally, at least one of the adjusted lance elements among the plurality of elongate adjustable lance elements is moved in a first direction, beyond a lower surface of the plate fin.

[0017] Optionally, at least one of the adjusted lance elements among the plurality of elongate adjustable lance elements is moved in a second direction, beyond a lower surface of the plate fin.

[0018] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, features, and techniques of the invention will become more apparent from the following description taken in conjunction with the drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0020] In the drawings, similar components and / or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label with a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label. Certain exemplary embodiments will now be described in greater detail by way of example only and with reference to the accompanying drawings in which: FIG. 1 illustrates a perspective view of an exemplary plate-fin heat exchanger. FIG. 2 illustrates a top view of a plate fin of the heat exchanger of FIG. 1. FIG. 3 illustrates a perspective sectional view of an exemplary contoured region of a plate fin. FIG. 4 illustrates a cross-sectional view of a contoured region of FIG. 3. FIG. 5 illustrates a cross-sectional view of a contoured region of a plate fin. FIG. 6 illustrates a cross-sectional view of a contoured region of a plate fin. FIG. 7 illustrates a cross-sectional view of a contoured region of a plate fin having inclined lance elements. DETAILED DESCRIPTION

[0021] The following is a detailed description of embodiments of the invention depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the invention. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

[0022] Various terms are used herein. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

[0023] In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the subject disclosure, the components of this invention. described herein may be positioned in any desired orientation. Thus, the use of terms such as "above," "below," "upper," "lower," "first", "second" or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the plate fin, tubes, holes, waves, lance elements, and corresponding components, described herein may be oriented in any desired direction.

[0024] Lanced fins have been used previously to provide a surface variation that enhances the transfer of heat energy between the fluids passing through the tubular members and over the plate fin surfaces in heat exchangers. Although the existing lanced fin design, in which the lance elements are moved upwardly or downwardly relative to the plate fin has been in use, there is a need to further improve and optimize the geometry of the existing lanced fins used in heat exchangers, which enhances the heat transfer process and the overall performance of the heat exchanger while keeping the overall cost of manufacturing lower.

[0025] Referring to FIG. 1, an exemplary plate-finned tube heat exchanger coil 100 is illustrated. As shown, the heat exchanger coil 100 includes a plurality of plate fins 200. Each plate fin 200 includes a sheet 202 having one or more holes 204 as shown in FIG. 2 formed therein for receiving one or more tubes 102 of the heat exchanger coil 100. The plurality of plate fins 200 are maintained together by oppositely positioned tube sheets (not shown) having holes therethrough in axial alignment with tube holes 204 of the plate fin 200. The plurality of tubes 102 can be laced through the holes 204 formed in the plate fins 200 and have their open ends joined together in fluid communication, which is secured to the tubes 102 by soldering, brazing, or the like. In one or more embodiments, there can be no interference between the tubes 102 and the fin sheets 202, however, the tubes 102 can only be arranged in contact with the plate fins 200.

[0026] In an implementation, a first fluid to be cooled or heated can flow through the tubes 102, and a second cooling or heating fluid can then be passed between the fin sheets 202 and over an exterior surface of the tubes 102 in a direction indicated by arrow A. Heat energy can be transferred from or to the first fluid through the tubes 102 and the plate fins 200 to or from the other fluid. The fluids may be different types; for example, the fluid flowing through the tubes can be a refrigerant, and the fluid flowing between plate fins 200 and over the tubes 102 can be air. However, embodiments where the fluids are the same type of fluid are also contemplated herein.

[0027] In one or more embodiments, the plurality of plate fins 200 can be staggered parallelly, such the holes 204 associated with each of the plate fins 200 for receiving the tubes 102 are also staggered or aligned. Further, each of the tubes 102 associated with the heat exchanger coils 100 can extend through the aligned holes 204 of plate fins 200. Referring to FIG. 2, the plurality of holes 204 can be arranged in one or more rows (202A, 202B) on the plate fin sheet 202, with all the holes 204 in a given row (202A, 202B) having a common centerline (C-C')) that can be oriented parallel to fin edges 202-1, 202-2. Further, between each row (202A, 202B) of tube holes 204 an inter-row area 206 having a flat profile can be present, which may reduce the pressure drop while the air is flowing along the surface of the plate fin 200. In one or more embodiments, a fin collar 304 can surround each of the tube holes as shown in detail in FIG. 3. The fin collar 304 can be configured to extend outwardly from the surface of the plate fin 200 in a first direction. By the length to which they extend from the surface of the fin, the plurality of fin collars 304 can serve to determine the spacing (also referred to as fin pitch) between the adjacent plate fins 200 in a given heat exchanger coil 100. The plurality of fin collars 304 may also function to ensure that there is a sufficient area of contact and a close mechanical fit, and therefore good thermal conduction, between the plate fins 200 and the tubes 102.

[0028] Referring to FIG. 3, a perspective view of a cross-section of the plate fin 200 of FIG. 2 taken in a plane (B-B') oriented generally transverse to the plate fin 200 is illustrated. As shown, in one or more embodiments, the plate fin 200 can include a contoured region 302 disposed between adjacent holes 204 in the same row (202A or 202B) on the fin sheet 202. The contoured region 302 may include a sinusoidal corrugation or sine-like waveform that runs parallel to the direction of the airflow A and perpendicular to the edges 202-1, 202-2 of the plate fins 200. The sinusoidal corrugation 302 can have at least one peak and at least one valley. As used herein, the term 'sinusoidal' is intended to cover waveforms or patterns that may be either true sine curves or approximations of a sine curve. Further, it should be understood that the term 'sinusoidal corrugation' may additionally include waveforms that represent a sine wave with a phase shift, for example resulting in a cosine-like waveform. Design requirements and practical considerations inherent in preparing tooling and manufacturing the fins mean that the waveforms may not necessarily be mathematically precise sine curves.

[0029] In one or more embodiments, as shown in FIGs. 4 to 7, the sinusoidal corrugation region 302 in each of the rows (202A, 202B) of the plate fin 200 can include three half-waves (W1 to W3) of a first wave size in the middle portion 302-1 (adjacent to the tube holes) of the corresponding row and two half-waves (W4, W5) of a second wave size on lateral ends 302-2 of the corresponding row with an overall count of 2.5 wave count per row. Accordingly, the sinusoidal corrugation 302 can have two peaks and one valley in the middle portion 302-1, and two valleys in the lateral ends 302-2. However, embodiments having a contoured region 302 including a sinusoidal corrugation extending less wave counts, such as a single wave count or 1.5 wave count, or more than 2.5 wave counts are also contemplated herein, and all such embodiments are well within the scope of the invention.

[0030] The term 'wave size' comprises wavelength and amplitude or height of the corresponding wave formed in the sinusoidal corrugation 302.

[0031] In one or more embodiments, the second wave size of the two half-waves (W4, W5) on the lateral ends 302-2 of the row can be smaller than the first wave size of the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row. Accordingly, the sinusoidal corrugation 302 in each row can have two peaks one valley (having a larger wave size) in the middle portion 302-1, and two valleys (having a smaller wave size) in the lateral ends 302-2. However, it should be understood that the wave size of the two half-waves (W4, W5) on lateral ends 302-2 can also be equal to or larger than the wave size of the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row, and all such embodiments are within the scope of the invention.

[0032] In one or more embodiments, the amplitude of the two half-waves (W1, W2) on the lateral ends 302-2 of the row can be smaller than the amplitude of the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row. Accordingly, the sinusoidal corrugation 302 in each row can have two peaks and one valley (having a larger amplitude) in the middle portion 302-1 and two valleys (having a smaller amplitude) in the lateral ends 302-2. However, it should be understood that the amplitude of the two half-waves (W4, W5) on lateral ends 302-2 can also be equal to or larger than the amplitude of the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row, and all such embodiments are within the scope of the invention.

[0033] In one or more embodiments, the sinusoidal corrugations 302 including at least one peak and at least one valley located at the contoured region of the plate fin 200 cannot have a continuous surface. Rather, the contoured region of the plate fin 200 can include at least one elongate lance element 306A, 306B, 306C (collectively designated as 306, herein) created and defined by longitudinal slits 308 formed in the contoured region 302. In a non-limiting embodiment of FIG. 3, the six longitudinal slits 308 in the contoured region 302 of the plate fin 200 form a total of seven lance elements 306. In other embodiments, as illustrated in FIGs. 4 to 7, the contoured region 302 can include eleven lance elements 306. Accordingly, it should be understood that a contoured region 302 having any suitable number of lance elements 306, such as five lance elements, six lance elements, eight lance elements, nine lance elements, ten lance elements, twelve lance elements, or thirteen lance elements for example, are within the scope of the invention.

[0034] Although the slits 308 are illustrated as extending perpendicular to the direction of the airflow A, or parallel to the edges 202-1, 202-2 of the plate fins 200, embodiments, where one or more of the slits 308 can be arranged at an angle to the edges of the plate fin 200, are also within the scope of the invention. In one or more embodiments, the lance elements 306 can only be located in the middle portion 302-1 of the sinusoidal corrugation regions that are substantially aligned with a portion of the tube hole 204. Accordingly, the waves or valleys on the lateral ends 302-2 of the corrugated region 302 and the inter-row region 206 formed between adjacent tube rows (202A, 202B) do not have any lance elements formed therein. Further, in one or more embodiments, the lance elements 306 can be located in the middle portion 302-1 as well as the lateral ends 302-2 of the sinusoidal corrugation region 302.

[0035] In one or more embodiments, a first portion of the lance elements can be fixed in place along the curvature of the sinusoidal corrugation 302. These lance elements are also referred to herein as fixed lance "elements." The second portion of the lance elements can be moved, for example, translated, after formation thereof, such as relative to the mean line of the sinusoidal corrugation, illustrated as the central plane P (see FIGs. 4 to 7). The lance elements (306A to 306C) that have an adjusted position may also be referred to herein as "adjusted lance elements." In the embodiment shown in FIG. 3, the sinusoidal corrugation 302 can include four fixed lance elements and three adjusted lance elements. In the non-limiting embodiment of FIGs. 4 to 7, the sinusoidal corrugation 302 can include six fixed lance elements and five adjustable lance elements.

[0036] In one or more embodiments, the plurality of elongate adjustable lance elements 306 can be offset relative to a central plane P arranged at a midpoint of an amplitude of the sinusoidal corrugation 302. As shown, the central plane P can extend generally through the sinusoidal corrugation 302 at a midpoint of the amplitude or height of the waveform. Accordingly, the distance between the plane P and a peak of the sinusoidal corrugation is equal to the distance between the plane P and a valley of the sinusoidal corrugation. In an embodiment, at least one adjusted lance element may be offset from the sinusoidal corrugation by a distance (O) referred to as lance offset as exemplified in FIGs. 4 to 7.

[0037] In one or more embodiments, the plurality of lance elements 306 can have a curved profile such that the lance elements 306 can maintain the curvature of the sinusoidal corrugation 302. Said another way, each of the plurality of elongate lance elements 306 has a cross-sectional shape that is a segment of the sinusoidal corrugation 302. The adjustable elongate lance elements 306 may be cut or lanced such that the slits 308 defining the adjustable lance elements 306 are configuration has a generally curved profile. In such embodiments, the wave count over which the sinusoidal corrugation 302 extends at least partially determines the total number of lance elements 306 included. Accordingly, an adjustable lance element 306A arranged at a peak of the sinusoidal corrugation 302 can have a generally concave curvature, and an adjustable lance element 306B, 306C arranged at a valley of the sinusoidal corrugation can have a generally convex curvature.

[0038] Although the adjustable lance elements 302 are illustrated as being disposed on opposite sides, at the peaks and valleys, of the sinusoidal corrugation, however, in one or more embodiments (not shown), at least one of the elongate adjustable lance elements among the plurality of elongate adjustable lance elements 306 cannot be present at the peaks or valleys, rather, created at a waveform between the adjacent peak and valley of the sinusoidal corrugated region 302.

[0039] In one or more embodiments, the plurality of lance elements 306 can have a substantially flat profile such that the lance elements 306 can remain substantially tangential to the waveform of the sinusoidal corrugation 302. The adjustable elongate lance elements 306 may be cut or lanced such that the slits 308 defining the adjustable lance elements 306 may have a generally planar profile.

[0040] Referring to FIG. 7, in one or more embodiments, the plurality of lance elements 306 can be inclined such that a non-uniform gap remains between a leading edge and a trailing edge of the corresponding lance element. In such embodiments, the lance elements 306 may have a planar profile as shown and / or a curved profile (not shown), which may be inclined towards one of the edges. In addition, in one or more embodiments, the inclined lance elements 306 can be disposed on opposite sides of the peaks and valleys of the sinusoidal corrugation, however, the inclined lance elements 306 cannot be present at the peaks or valleys, rather, can be created at a waveform between the adjacent peak and valley of the sinusoidal corrugated region.

[0041] In one or more embodiments, at least one of the lance elements 306A to 306C among the plurality of elongate adjustable lance elements 306 can be offset such that a first gap created between a leading edge, upstream of airflow direction A, of the corresponding lance elements and a surface of the plate fin 200 is greater than a second gap created between a trailing edge, opposite to the leading edge, of the corresponding lance element 306 and the surface of the plate fin 200. These inclined lances elements 306 and profile of the corrugated region 302 can form a jet of the airflow, disrupting the boundary layer and reducing thermal wake effects, thereby enhancing the heat transfer significantly

[0042] In one or more embodiments, the plurality of elongate adjustable lance elements 306 in the corrugated region can have a non-uniform lance width. For instance, the lance elements 306A associated with waves W1, W3 at the two peaks and the lance element 306B associated with the wave W2 at one valley in the middle portion 302-1 of each row can have the same or different lance widths. Similarly, the lance elements 306C associated with the two waves W4, W5 at the two valleys on the lateral ends 302-2 of each row can have the same or different lance widths. In addition, in one or more embodiments, the plurality of elongate adjustable lance elements 306 in the corrugated region can have a non-uniform lance offset with respect to the central plane. For instance, the lance elements 306A, 306B at the two peaks and one valley in the middle portion 302-1 of each row can have the same or different lance offset with respect to the central plane P. Similarly, the lance elements 306C at the two valleys on the lateral ends 302-2 of each row can have the same or different lance offset.

[0043] In one or more embodiments, the width of the lance elements 306C associated with the two half-waves (W4, W5) (having the second wave size) on lateral ends 302-2 of the row can be smaller than the width of the lance elements 306B, 306C associated with the three half-waves (W1 to W3) (having the first wave size) in the middle portion 302-1 of the corresponding row. However, it should be understood that the width of lance elements 306C associated with the two half-waves (W4, W5) on lateral ends 302-2 can also be equal or larger than the width of lance elements 306B, 306C associated with the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row, and all such embodiments are within the scope of the invention.

[0044] In one or more embodiments, the amplitude of the lance elements 306C associated with the two half-waves (W4, W5) (having the second wave size) on lateral ends 302-2 of the row can be smaller than the amplitude of the lance elements 306B, 306C associated with the three half-waves (W1 to W3) (having the first wave size) in the middle portion 302-1 of the corresponding row. However, it should be understood that the amplitude of lance elements 306C associated with the two half-waves (W4, W5) on lateral ends 302-2 can also be equal or larger than the amplitude of lance elements 306B, 306C associated with the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row, and all such embodiments are within the scope of the invention.

[0045] Referring to FIG. 4, in one or more embodiments, at least one of the adjusted lance elements 306A to 306C can be moved in a downward direction, beyond a lower surface of the plate fin 200. This downward direction is a second direction, opposite the first direction in which the fin collar 304 extends from the plate fin 200. As shown, each of the adjusted lance elements originated 306B, 306C from a valley of the sinusoidal corrugation 302 can be moved downwardly away from plane P, such that an upper surface of the lance element 306B, 306C is positioned vertically beneath a lower surface of the plate fin 200. As a result of this movement, the distance between the lance element 306B, 306C and the plane P increases. Further, each of the lance elements 306A originating from a peak of the sinusoidal corrugation 302 may be similarly moved in the same second, downward direction such that an upper surface of the lance element 306A is positioned vertically beneath the lower surface of the plate fin 200. However, the downward movement can move the lance elements 306A toward the plane P such that the distance between the lance elements 306A and the plane P decreases. Accordingly, the distance between the plane P and the lance elements 306B, 306C can be different than the distance between the lance elements 306A and the plane P. In one or more embodiments, the distance by which adjacent lance elements 306A to 306C are offset from the sinusoidal corrugation, 302 in a direction perpendicular to the direction of flow A, such as relative to the plane P for example, also referred to herein as the lance offset, may be uniform.

[0046] In one or more embodiments, as shown in FIG. 5, at least one lance element 306B, 306C arranged at a valley of the sinusoidal corrugation can be moved in an opposite direction as at least one lance element 306A arranged at a peak of the sinusoidal corrugation 302. As shown, each of the lance elements 306B, 306C arranged at a valley of the sinusoidal corrugation 302 can be moved in the second direction, downwardly away from plane P. As a result, an upper surface of the lance element 306B, 306C can be positioned vertically beneath the lower surface of the plate fin 200. Because of this movement, the distance between the lance element 306B, 306C, and the plane P can increase. Similarly, each of the lance elements 306A formed at a peak of the sinusoidal corrugation can be moved in the first, upward direction in which the fin 200 collar extends from the plate fin 200. With this movement away from the plane P, the lower surface of the lance element 306A may be positioned vertically above the upper surface of the plate fin 200. In one or more embodiments, the total distance that each lance element (306A to 306C) can be moved in a direction perpendicular to the direction of flow A, such as relative to the plane P for example, may be equal or may vary.

[0047] Referring to FIG. 6, in one or more embodiments, the plurality of elongate adjustable lance elements (306A to 306C) can be offset relative to a central plane P arranged at a midpoint of an amplitude of the sinusoidal corrugation 302. As shown, each of the adjusted lance elements 306B, 306C originating from a valley of the sinusoidal corrugation can be moved upwardly towards the central plane P, such that the bottom surface of the corresponding lance element 306B, 306C is positioned vertically above a lower surface of the plate fin 200. Further, each of the lance elements 306A originating from a peak of the sinusoidal corrugation may be similarly moved in the downward direction such that an upper surface of the corresponding lance element 306A is positioned vertically beneath the lower surface of the plate fin 200. As a result of this movement, the distance between the lance elements (306A to 306C) and the plane P decreases.

[0048] It is to be appreciated that the profile of the corrugated region and the lance elements in the plate fin can form the jet of the airflow, disrupting the boundary layer and reducing thermal wake effects, thereby enhancing heat transfer significantly. Thus, this, invention improves and optimizes the geometry of the existing lanced fins used in heat exchangers, by enhancing the heat transfer process and the overall performance of the heat exchanger while keeping the overall cost of manufacturing the plate fin lower.

[0049] While the invention has been described with reference to exemplary 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 as defined by the appended claims. Modifications may be made to adopt a particular situation or material to the teachings of the invention without departing from the scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention includes all embodiments falling within the scope of the invention as defined by the appended claims.

[0050] In interpreting the specification, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms "comprises" and "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C ....and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.

Claims

1. A heat exchanger (100) comprising a plurality of plate fins (200), at least one plate fin (200) comprising: a plurality of holes (204) arranged in one or more rows (202A, 202B); and a contoured region (302) formed adjacent to one of the plurality of holes (204) and having a sinusoidal corrugation (302), the contoured region (302) comprising a plurality of elongate adjustable lance elements (306; 306A-306C); wherein the sinusoidal corrugation (302) in each of the rows (202A, 202B) comprises three half-waves (W1-W3) of a first wave size in a middle portion (302-1) of the corresponding row (202A, 202B), and two half-waves (W4, W5) of a second wave size on lateral ends (302-2) of the corresponding row (202A, 202B), wherein the second wave size is smaller than the first wave size, characterized in that the sinusoidal corrugation (302) comprises at least one peak and at least one valley, wherein at least one elongate adjustable lance element (306; 306A-306C) among the plurality of elongate adjustable lance elements (306; 306A-306C) is formed at the at least one valley and / or the at least one peak.

2. The heat exchanger (100) of claim 1, wherein the plurality of elongate adjustable lance elements (306; 306A-306C) is offset relative to a central plane (P) arranged at a midpoint of an amplitude of the sinusoidal corrugation (302).

3. The heat exchanger (100) of any one of claims 1 and 2, wherein the plurality of elongate adjustable lance elements (306; 306A-306C) has a non-uniform lance width.

4. The heat exchanger (100) of any one of claims 1 to 3, wherein the plurality of elongate adjustable lance elements (306; 306A-306C) has a non-uniform lance offset.

5. The heat exchanger (100) of any one of claims 1 to 4, wherein width of the lance elements (306A, 306B) associated with the waves (W1-W3) having the first wave size is greater than width of the lance element (306C) associated with the waves (W4, W5) having the second wave size.

6. The heat exchanger (100) of any one of claims 1 to 5, wherein amplitude of the lance elements (306A; 306B) associated with the waves (W1-W3) having the first wave size is greater than amplitude of the lance element (306C) associated with the waves (W4, W5) having the second wave size.

7. The heat exchanger (100) of any one of claims 1 to 6, wherein an inter-row area (206) between adj acent half-waves (W4, W5) associated with the adj acent rows (202A, 202B) among the one or more rows (202A, 202B) has a planar profile.

8. The heat exchanger (100) of any one of claims 1 to 7, wherein the sinusoidal corrugation (302) comprises at least one peak and at least one valley, wherein at least one elongate adjustable lance element (306; 306A-306C) among the plurality of elongate adjustable lance elements (306; 306A-306C) is formed at a waveform between the at least one valley and the at least one peak.

9. The heat exchanger (100) of any one of claims 1 to 8, wherein at least one elongate adjustable lance element (306; 306A-306C) among the plurality of elongate adjustable lance elements (306; 306A-306C) is offset such that a first gap created between a leading edge, upstream of airflow direction (A), of the corresponding lance elements (306; 306A-306C) and a surface of the plate fin (200) is greater than a second gap created between a trailing edge, opposite to the leading edge, of the corresponding lance element (306; 306A-306C) and the surface of the plate fin (200).

10. The heat exchanger (100) of any one of claims 1 to 9, wherein at least one elongate adjustable lance element (306; 306A-306C) among the plurality of elongate adjustable lance elements (306; 306A-306C) has a curved profile11. The heat exchanger (100) of any one of claims 1 to 10, wherein at least one elongate adjustable lance element (306; 306A-306C) among the plurality of elongate adjustable lance elements (306; 306A-306C) has a flat profile.

12. The heat exchanger (100) of any one of claims 1 to 11, wherein at least one elongate adjustable lance element (306; 306A-306C) among the plurality of elongate adjustable lance elements (306; 306A-306C) is inclined, optionally wherein the at least one elongate adjustable lance element (306; 306A-306C) is inclined such that a non-uniform gap is between a leading edge and a trailing edge of the corresponding lance element (306; 306A-306C).

13. The heat exchanger (100) of any one of claims 1 to 12, wherein at least one of the adjusted lance elements (306; 306A-306C) among the plurality of elongate adjustable lance elements (306; 306A-306C) is moved in a first direction, beyond a lower surface of the plate fin (200).

14. The heat exchanger (100) of any one of claims 1 to 13, wherein at least one of the adjusted lance elements (306; 306A-306C) among the plurality of elongate adjustable lance elements (306; 306A-306C) is moved in a second direction, beyond a lower surface of the plate fin (200).

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