Method for assembling plate-fin heat exchanger and plate-fin heat exchanger

Abstract

The present disclosure relates to a method of assembling a plate pack of a plate-fin heat exchanger (1) comprising a plurality of flat plates (4, 4 ') and a plurality of fin plates (3), where each flat plate (4, 4') comprises peripheral flank portions (4a, 4b; 4a ', 4b'). Each flank portion is permanently joined to an adjacent flat plate (4 ') such that a longitudinally extending flow channel (12) is formed between the adjacent flat plates (4, 4'), and wherein each flat plate (4, 4 ') comprises a heat exchange portion (14) which is arranged between the peripheral flank portions (4a, 4b; 4a ', 4b') in a transverse direction. The fin plate (3) comprises a plurality of longitudinally extending fins (32) arranged in the heat exchange portion (14), the fins (32) forming parallel guide channels (34) for a first heat exchange medium (18) and a second heat exchange medium (22), respectively, in a transverse direction. The fin plate (3) and the flat plate (4, 4 ') are permanently attached to each other. The method includes providing a fin plate larger than the heat exchange portion in the transverse direction, and placing the fin plate onto a flat plate in the group prior to permanently joining the plates together. In this manner, the size of the bypass gap may be minimized.

Description

Technical Field

[0001] The invention relates to a method for assembling a plate package for a plate-fin heat exchanger and a plate-fin heat exchanger as defined in the preambles of the independent claims appended hereto. Background Art

[0002] A plate heat exchanger or PHE is a heat exchanger that typically comprises a plurality of metal heat exchange plates arranged in an aligned manner and such that flow channels are formed between the plates. The heat exchange plates are used to separate two fluids and to transfer heat between the fluids. In a plate heat exchanger, fluids of different temperatures flow through flow channels, which may include fin plates providing several flow channels to provide an increased heat exchange area. The fins may be provided by corrugated sheet metal plates. The heat exchanger plates may be arranged as a group between end plates, and all the plates may be joined by brazing. In some variations, pressure plates may be used that press the heat exchanger plates and the end plates toward each other. In order to be able to transfer heat between fluids, flow channels for the respective fluids are required, and this may be achieved in different ways depending on the type of heat exchanger and the fluid in question.

[0003] There are different types of plate heat exchangers (PHEs), and plate heat exchangers can be adapted to different types of hot fluids. Known PHEs include, for example, brazed heat exchangers, in which the flow of hot fluids is generally arranged in separate channels in a countercurrent manner. No gaskets or the like are required to separate the fluids. In the heat exchanger, fluids of initially different temperatures flow and heat is transferred from one fluid to another.

[0004] Plate fin heat exchangers are well known in the art. An example of a brazed plate fin heat exchanger is disclosed by US4673551.

[0005] Although brazed plate fin heat exchanger solutions exist, there is still a need for improvement, especially in the assembly of such plate heat exchangers. There is a particular need to simplify the assembly. There is also a need to improve the thermal performance of the plate heat exchangers. Summary of the invention

[0006] In a finned plate heat exchanger, finned plates and flat plates are assembled alternately on top of each other to form a plate pack with flow channels. After reaching the desired pack height, the plates are permanently joined together by, for example, brazing, which requires a process using heat. In conjunction with the present disclosure, it is noted that after brazing, bypass voids are formed on the respective longitudinal side ends of the finned plates. The voids deteriorate the thermal performance of the heat exchanger, and they are therefore undesirable. Therefore, an object of the present invention is to minimize the size of the voids.

[0007] It is therefore an object of the present invention to mitigate, alleviate or eliminate one or more of the above identified disadvantages in the prior art. It is an object to provide a solution for a heat exchanger which may provide improved thermal performance. It is also an object to provide a robust heat exchanger.

[0008] Another object is to provide a simple method for assembly of the plate pack.

[0009] The above mentioned objects are achieved by the invention as defined in the appended claims.

[0010] According to a first aspect, a method for assembling a plate group of a plate-fin heat exchanger is provided, the plate group comprising a plurality of flat plates and a plurality of fin plates. Each flat plate comprises peripheral flank portions located on two opposite longitudinal sides of the respective flat plate. Each flank portion is permanently attached to an adjacent flat plate so that a longitudinally extending flow channel is formed between the adjacent flat plates, and wherein each flat plate comprises a heat exchange portion having a transverse extension between the peripheral flank portions. The fin plate comprises a plurality of longitudinally extending fins arranged in the heat exchange portion, the fins forming parallel guide channels for a first heat exchange medium and a second heat exchange medium, respectively, in a transverse direction. The method comprises the following steps:

[0011] i. providing a plate comprising peripheral wing portions located on opposite longitudinal sides of the plate, the wing portions defining a heat exchange portion of the plate;

[0012] ii. providing a fin plate having longitudinally extending fins, the fin plate having a lateral extension greater than the lateral extension of the heat exchange portion of the flat plate;

[0013] iii. Pressing the opposite sides of the fin plate toward each other in a lateral direction so that the fin plate is assembled between the side wing portions and on the heat exchange portion of the plate;

[0014] iv. placing the next plate in the group on top of the previous fin plate in the group so that at least a portion of the next plate contacts the fins of the fin plate assembled in the heat exchange portion of the previous plate and so that the side wing portions of the plate are connected to the side wing portions of the next plate; and

[0015] v. Repeat steps i)-iv) until the number of plates in the group reaches the target number, and

[0016] vi. Permanently join the flat plate including the side wing portions and the fin plate together.

[0017] By this method, a plate pack with improved thermal performance is provided. This is achieved due to the overdimensioning of the lateral extension of the fin plates compared to the surface on which they will be positioned. It is thus possible to minimize the size of the bypass gaps formed after permanent joining of the plates in the pack.

[0018] In step iv), the wing parts of a plate can be connected to the wing parts of the next plate so that they overlap in the height direction of the group. In this way, a compact structure can be provided.

[0019] The heat exchange portion of the plate may transition to the wing portion via a fillet portion on the respective side of the plate. In step iii), the pressing of the wing portion may include minimizing the radius of the fillet portion. In this way, the fins may be brought closer to the wing before permanent bonding. When the group is heated during permanent bonding, the fins remain closer to the wing and thus the size of the bypass gap may be reduced. As a result, thermal performance may be further improved.

[0020] Therefore, step iii) may further include minimizing the radius so that the radius is less than the height of the flow channel, preferably less than 0.5h, and / or so that the radius is less than twice the thickness of the plate, preferably less than 1.1 times the thickness of the plate, and / or so that the distance between the inner surface of the wing portion and the outermost part of the fin closest to the wing portion is less than the height of the flow channel, preferably less than 0.5h at the midpoint of the height of the flow channel.

[0021] In step iii), pressing may include adjusting a first distance between an inner surface of the wing portion and an outermost portion of a fin closest to the wing portion measured at a midpoint of the height of the flow channel such that the first distance is smaller than a second distance between two adjacent fins, or such that the first distance is smaller than the height of the flow channel. In this way, the size of the bypass gap formed during permanent bonding may be minimized.

[0022] The first distance may be less than 0.7h, preferably less than 0.5h at the midpoint of the height of the flow channel. The smaller the distance, the smaller the bypass gap.

[0023] Pressing may alternatively or additionally include adjusting a first hydraulic diameter between an inner surface of the wing portion and an outermost portion of a fin closest to the wing portion so that the first hydraulic diameter is equal to or smaller than a second hydraulic diameter between two adjacent fins measured at a point along the longitudinal extension of the fin where the hydraulic diameter is smallest.

[0024] Step ii) may comprise providing a fin plate, wherein the length of the fin wall of the outermost fin is less than the height of the flow channel and the fin is open towards the heat exchange portion of the plate. In this way, the outermost fin can be brought into close proximity with the inner surface of the wing and thus the bypass gap can be further minimized. The length of the fin wall may be less than the height h of the flow channel, preferably less than 0.5h. Alternatively, the length of the fin wall is less than 0.25h.

[0025] The permanent joining in step vi) can be performed by means of brazing or by means of material joining of the heat transfer plates by application of a melting inhibitor composition applied to the heat transfer plates before heating.

[0026] According to another aspect, a plate-fin heat exchanger is provided, comprising: a plate group, the plate group comprising a plurality of flat plates and a plurality of fin plates, wherein each flat plate comprises a peripheral wing portion located on two opposite longitudinal sides or lateral sides of the corresponding flat plate. Each wing portion is permanently connected to an adjacent flat plate, appropriately connected to its wing portion. The wing portions are connected so that a longitudinally extending flow channel is formed between adjacent flat plates. Each flat plate comprises a heat exchange portion having a transverse extension between the peripheral wing portions. The fin plate comprises a plurality of longitudinally extending fins, which are arranged in the heat exchange portion of the flow channel between adjacent flat plates and are in contact with the adjacent flat plates. The fins form parallel guide channels for a first heat exchange medium and a second heat exchange medium in a transverse direction, respectively. The heat exchange portion of the flat plate transitions to the wing portion via a fillet portion on the corresponding side of the flat plate, and wherein the wing portion is pressed so that the radius of the fillet portion is minimized and is smaller than the height of the flow channel, preferably smaller than 0.5h. Alternatively or additionally, the radius is adjusted to be less than twice the thickness of the flat plate, preferably less than 1.1 times the thickness of the flat plate (4). Alternatively or additionally, a first distance between the inner surface of the wing and the outermost fin measured at the midpoint of the height of the flow channel is smaller than a second distance between two adjacent fins, or such that the first distance is smaller than the height of the flow channel, wherein the length of the fin wall of the outermost fin is smaller than the height of the flow channel, and the fin is open towards the heat exchange portion of the plate. In this way, a bypass gap formed in the area between the inner surface of the wing and the outermost fin during permanent attachment can be minimized. Thus, by adjusting the distance between the inner surface of the wing and the outermost fin and / or the bending radius of the wing, the bypass gap is configured to be minimized.

[0027] According to a variant, a first hydraulic diameter between the inner surface of the wing portion and the outermost portion of the fin closest to the wing portion can be adjusted to be equal to or smaller than a second hydraulic diameter between two adjacent fins measured at the point where the hydraulic diameter is smallest along the longitudinal extension of the fin. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above objects as well as additional objects, features and advantages of the present invention will be more fully appreciated by referring to the following illustrative and non-limiting detailed description of exemplary embodiments of the present invention when viewed in conjunction with the accompanying drawings.

[0029] Figure 1 is a schematic diagram showing a plate heat exchanger in perspective view.

[0030] Figure 2 The plate-fin heat exchanger assembled according to the prior art method is shown along the Figure 1 Schematic cross-sectional view of line XX shown in .

[0031] Figure 3a-3c Different shapes of fins are shown.

[0032] Figure 4 Steps i) to iii) of the method according to the invention are shown.

[0033] Figure 5 A prior art plate fin heat exchanger is shown in which the fins are limited by the radius of the bending curve of the plate, thereby obtaining a large bypass gap between the side wings of the plate and the outermost fins of the fin plate.

[0034] Figure 6 A plate-fin heat exchanger obtained by the method is shown, in which the size of the bypass gap is minimized by minimizing the bending radius of the flanks of the plates.

[0035] Figures 7a-7d An example of a fin cut to obtain a minimum size for a bypass gap is shown.

[0036] Figure 8 The plate package with minimized bypass gaps obtained by the method according to the invention is shown along the Figure 1 Schematic cross-sectional view of line XX shown in . DETAILED DESCRIPTION

[0037] Today's process technology generally involves heat exchangers for improving the energy efficiency of the process. It has been found that the above objects are achieved by a heat exchanger comprising a plate pack assembled according to the method of the present invention. It has been noted that improved thermal performance can be obtained, and the solution of the present invention will now be described with reference to the accompanying drawings showing examples of the present invention. However, the present invention may be embodied in other forms and should not be construed as limited to the exemplary embodiments disclosed herein. The disclosed embodiments are provided to fully convey the scope of the present invention to the skilled person.

[0038] According to a first aspect of the invention, a method for assembling a plate package of a plate fin heat exchanger is provided. Figure 1 and Figure 2The plate package 2 of the plate-fin heat exchanger 1 thus comprises a plurality of flat plates 4 and a plurality of fin plates 3 .

[0039] In general, in this application, by a flat plate is meant a plate without any pressed channels or fin designs. By a fin plate is meant a plate including pressed channels or fin designs. The plate is typically a metal plate, which includes a metal or metal alloy, or is composed of a metal or metal alloy. In general, the material for the fin plate and the flat plate may be any suitable and commonly used material, such as stainless steel, aluminum, copper, nickel, tantalum, titanium or their alloys, but is not limited thereto. For the fin plate and the flat plate, the material may be the same or different. In general, both the fin plate and the flat plate may have a thickness from 0.08 to 5.0 mm, or from 0.3 to 3.0 mm. In a group, the thickness of the fin plate may be the same, or may be different. The thickness of the flat plate may be from 0.25 to 5 mm, and in a group, except for the end plate which may be thicker, the thickness may be the same for all flat plates. The fin plate may be thinner, and may have a thickness from 0.08 to 5 mm, or from 0.1 to 1 mm, and in the entire group, they may have the same thickness, or they may initially have the same thickness. However, during the pressing operation, the thickness of the fin plate may be affected, whereby the final thickness of the fin plate may be less than the thickness of the flat plate. Therefore, the metal plate thickness for the fin plate may be thicker or thinner than that for the flat plate, but preferably thinner than the thickness of the flat plate.

[0040] The longitudinal direction L through the heat exchanger means extending between the respective inlet port 16a and outlet port 20a or between the inlet port 16b and outlet port 20b and as shown in FIG. Figure 1 The transverse direction T is a direction perpendicular to the longitudinal direction L in the same plane. The height direction H is a direction extending perpendicular to the plane of the longitudinal-transverse direction.

[0041] Each plate 4 comprises two opposite longitudinal sides L of the corresponding plate and Figure 2 The peripheral side wing parts 4a, 4b shown in Figure 2 The assembled panel set 2 is shown after permanent joining of the panels. Figure 2 FIG. 4 shows the transition of the wing portion 4a of the plate 4 to the edge portion 5a. The wing portion 4b in the opposite longitudinal side can transition to the edge portion 5b in a symmetrical manner, which is shown in FIG. Figure 2. The edge portion may be omitted. In group 2, each wing portion 4a and 4b is permanently connected to the wing portion of the adjacent flat plate 4, so that a longitudinally extending flow channel 12 is formed between the adjacent flat plates 4. In this flow channel or channel, the cold fluid and the hot fluid are arranged to flow in a separation channel 34 formed by the fins 32 of the fin plate. Each flat plate 4 includes a heat exchange portion 14, which has a lateral extension between the peripheral wing portions 4a, 4b, and the fins of the fin plate are arranged to be connected to the heat exchange portion 14. Therefore, the fin plate 3 includes a plurality of longitudinally extending fins 32 arranged in the heat exchange portion 14 of the flow channel 12 between the adjacent flat plates 4. The fins 32 form parallel guide channels 34 for the first heat exchange medium 18 and the second heat exchange medium 22 in the lateral direction.

[0042] The longitudinally extending fins 32 may have different cross-sectional shapes, which may also vary along the longitudinal extension and / or the transverse extension. Figure 3a Examples of different fin shapes are shown in Figs. )-c). In general, the fins may have a wave shape and be parallel in the transverse direction, each wave having a crest (p) and a trough (t) (see Figs. Figure 5 ). The fin may be substantially straight along the longitudinal extension L. However, the fin may have another shape along the longitudinal extension. For example, the shape may be wavy along the longitudinal extension, such as Figure 3c As shown in . The fins may have a wavy shape in cross section, for example, a substantially sinusoidal wave shape. Alternatively, as Figure 3a and 3b As shown in Figure 1, the fins may have a rectangular or triangular cross section. Another variant may be a so-called offset strip shape, in which the wave shape resembles a rectangular block that is shifted in a wave-like manner in the transverse direction. In addition, the fins may have different surface treatments along the fins, and they may be perforated or louvered, for example.

[0043] Figure 2 Bypasses 30 (only one is depicted with a reference symbol) in the flow channels 12 of the heat exchanger plate package 2 after permanent joining are shown. The bypasses 30 are gaps between the outermost parts 38 of the fin walls 36 and the flanks 4a, and correspondingly between the flanks 4b on the opposite lateral side of the plate and the corresponding outermost parts 38 of the fin walls 36 on that side of the fin plate 3. Figure 2 In the bypass gap 30, the bypass gap 30 is large. In the bypass gap 30, no heat exchange occurs between fluids with different temperatures. Therefore, the bypass reduces the thermal performance of the heat exchanger. The object of the present invention is to minimize the size of the bypass in the flow channel and thus improve the thermal performance of the heat exchanger.

[0044] A heat exchanger having improved thermal performance is obtainable by the process of the invention and reference is now made to Figure 4, Figure 4 1 and 2. Steps i) to iii) of the invention are shown. In a first step i), a plate 4 is provided which comprises peripheral flank portions 4a and 4b located on opposite longitudinal sides (ie lateral sides) of the plate. Figure 2 As described, the wing portions 4a, 4b delimit the heat exchange portion 14 of the plate. In step ii), a fin plate 3 having longitudinally extending fins 32 is provided. The fin plate 3 has a lateral extension that is greater than the lateral extension of the heat exchange portion 14 of the plate. In the following step iii), the opposite sides of the fin plate 3 are pressed toward each other in the lateral direction so that the fin plate 3 is assembled between the wing portions 4a and 4b and on the heat exchange portion 14 of the plate. When the fin plate 3 is placed on the plate 4 and the fin plate 3 is released from pressing the lateral sides toward each other, the fin plate 3 can expand so that the lateral sides are brought together toward the wing portions 4a and 4b, as shown in FIG. Figure 4 Indicated by reference symbol iii)'.

[0045] To provide a plate package 2, the desired number of flat plates 4 and fin plates 3 are stacked on top of each other. Figure 5 , to illustrate how the group 2 can be provided. Therefore, after step iii), the next step is step iv), in which the next flat plate 4' is placed on top of the previous fin plate 3, so that at least a part of the next flat plate 4' is in contact with the fins 32 of the fin plate 3 assembled in the heat exchange portion 14 of the previous flat plate 4. Therefore, the flat plates 4, 4' together with the fins 32 form guide channels 34 for the respective first heat exchange medium 18 and the second heat exchange medium 22. The side wing parts 4b, 4b' of the flat plates 4, 4' and (in a similar way) 4a and 4a' (not shown in the figure) overlap in the height direction h of the group 2. As shown in FIG. Figure 5 As can be seen in FIG. 4 , the heat exchange portion 14 of the plate 4 transitions to the wing portion 4 b (and similarly to 4 a ) via a rounded portion 44 on the respective side of the plate 4 .

[0046] In step v) of the method, steps i-iv are repeated until the number of plates in the group reaches a target number.

[0047] The method further comprises a step vi) comprising permanently joining the flank portions 4a, 4a' and 4b, 4b' on the respective longitudinal sides of the adjacent flat plates 4, 4' to provide a plate pack. The permanent joining may be performed, for example, by brazing or by means of material joining of the heat transfer plates by application of a melting inhibitor composition applied to the heat transfer plates before heating, for example, as discussed in WO2013144211. Thus, a permanent joint may be formed by a joining method in which the plates are subjected to heat below the melting point of the heat transfer plates. Such joining methods may be one of brazing with an added brazing material in the form of a foil, paste or powder comprising, for example, copper or nickel, or by means of material joining of the heat transfer plates by application of a melting inhibitor composition applied to the heat transfer plates before heating.

[0048] By manufacturing a plate package as described above, it is possible to minimize the gaps for bypass. This in turn improves the thermal performance of the heat exchanger.

[0049] The flank portions 4a, 4b on respective longitudinal sides of the plate 4 may be provided upstream of or together with step i) in the method. Pressing may be performed by means of a pressing tool, which may be any suitable metalworking tool known in the art.

[0050] refer to Figure 5 , which shows a diagram of a plate package not manufactured by the method according to the invention. The radius r limits the fins 32 to be located closer to the inner surface 42 of the flanks 4a, 4b. Therefore, a large bypass gap 30 is present. Figure 5 Further shown is the gap 30 formed between the inner surface 42 of the wing portion 4b and the outermost portion 38 of the fin 32 , which has a first distance d1 between the inner surface 42 of the wing portion 4b and the outermost fin 38 at the midpoint MH of the overall height of the flow channel 12 . Figure 5 Also shown is a distance d2, which refers to the distance between two adjacent fins 32 along the transverse extension T of the fin plate. The distance d1 is greater than the distance d2. Figure 5 In FIG. 4 , the radius is relatively large and, therefore, the distance d1 between the outermost fin 38 and the inner surface of the wing 42 measured at the midpoint of the height (MH) is relatively large.

[0051] exist Figure 6 A variation of the plate set is shown in , in which the radius (r) of the filleted portion has been minimized. Figure 6The plate pack manufactured by the method according to the present invention is shown, at the midpoint MH of the height of the total height of the flow channel 12, the corresponding distance d1 between the inner surface 42 of the wing portion 4b and the outermost fin 38 is smaller than the distance d2 between two fins 32. The first distance (d1) between the inner surface 42 of the wing portion 4b and the outermost fin 38 closest to the wing portion 4b is adjusted so that the first distance (d1) will be equal to or smaller than the second distance (d2) between two adjacent fins 32. Alternatively, the first distance d1 can be adjusted to be smaller than the height (h) of the flow channel 12. Figure 5 In the case of Figure 6 in Figure 6 In the embodiment, the distance d1 at the midpoint MH of the height of the flow channel is minimized and is less than 0.5h.

[0052] Alternatively or additionally, the hydraulic diameter dh may be used as a reference for adjustment of the gap size. In this case, the hydraulic diameter is adjusted so that a first hydraulic diameter (dh1) between the inner surface of the wing portion and the outermost portion of the fin closest to the wing portion is equal to or less than twice a second hydraulic diameter (dh2) between two adjacent fins.

[0053] The hydraulic diameter indicates the

[0054] dh=4A / P,where

[0055] A = cross-sectional area of ​​flow (A);

[0056] P = wetted perimeter of the cross section.

[0057] That is, the metric is between the cross-sectional area of ​​the flow (A) and the wetted perimeter of the cross section (P). This metric is applicable when the flow channel is non-circular, which is the case in this application.

[0058] Further references Figures 7a-7d , where different types of fin cuts are shown. Figure 7a The conventional fin cutting is shown in FIG. Figure 5 and Figure 6 The disadvantage of this cutting is that the radius of the bend of the wing 4b will limit the position of the outermost fin 38 relative to the inner surface 42 of the wing. According to the present application, the outermost fin 38 can be cut in combination with the step (ii) comprising providing the fin plate 3. The fin wall 36 of the outermost fin 38 is then cut to a height less than the height of the flow channel 12. Figure 7b In the embodiment, the height is about 0.5h and the fins are open towards the heat exchange portion 14 of the plate 4. By open is meant that the fins have their peaks in contact with the next plate 4' and the outermost portion 38 has no valleys in contact with the previous plate 4. Figure 7c and 7dIn the embodiment, the height is even shorter and may be less than 0.25h or less than 0.1h, and the fins are open toward the heat exchange portion 14 of the plate 4. In the embodiment in which the height is less than 0.25h and near the peak of the fin Figure 7d , provides the optimum fin cut when trying to minimize the gap for bypass.

[0059] Now refer to it again Figure 5 and Figure 6 , in which the plate group is schematically shown before the permanent joining of the group. The pressing of the flank portions 4a, 4b of the flat plate 4 can be adjusted so that a rounded portion 44 with a radius (r) is provided as a transition between the heat exchange portion 14 and the respective flank portion 4a, 4b. Adjustment can thus be made by adjusting the radius r. Figure 5 The bending radius r is Figure 6 The big one. Figure 6 A variation of the plate group 2 obtained by the present method is shown. As described above in the general description of the invention, the adjustment of the radius (r) can be performed in step i). For example, step i) may further include adjusting the radius (r) so that the distance (d1) between the inner surface of the wing portion 4b and the outermost fin 38 closest to the wing portion 4b is less than the height (h) of the flow channel 12 at the midpoint (MH) of the height, preferably less than 0.5h. Alternatively, minimization is performed so that the radius (r) is less than twice the thickness (d4) of the flat plate 4, preferably less than 1.1 times the thickness (d4) of the flat plate 4. In some cases, the radius may be about 1 / 5 of the thickness of the flat plate.

[0060] The method further comprises permanently joining the flank portions 4a, 4b and 4a', 4b' of adjacent flat plates 4, 4' to provide a plate package 2. The permanent joining can be performed by means of brazing or by means of material joining of the heat transfer plates by application of a melting inhibitor composition applied to the heat transfer plates before heating. The invention also relates to a plate heat exchanger 1 comprising a plate package 2 manufactured by the method as described above.

[0061] refer to Figure 8 , which shows a schematic diagram of a plate group 2 obtained by the present method. Figure 1 In the plane XX shown in Figure 2. Group 2 comprises a plurality of flat plates 4, 4' and a plurality of fin plates 3, wherein each flat plate 4, 4' comprises peripheral flank portions 4a, 4a' (4b and 4' are not shown) located on two opposite longitudinal sides of the corresponding flat plate. Each flank portion 4a, 4a' is permanently connected to the flank portion of the adjacent flat plate 4 so that a longitudinally extending flow channel 12 is formed between the adjacent flat plates 4, 4'. Each flat plate 4, 4' comprises a heat exchange portion 14 having a transverse extension between the peripheral flank portions 4a, 4b; 4a', 4b'. The fin plate 3 comprises a plurality of longitudinally extending fins 32, which are arranged in the heat exchange portion 14 of the flow channel 12 between the adjacent flat plates 4. The fins 32 form parallel guide channels 34 for the first heat exchange medium 18 and the second heat exchange medium 22 in the transverse direction, respectively. Basically as described above, a first distance (d1) between the inner surface 42 of the wing portion and the outermost fin 38 closest to the wing portion at the level of the mid-height MH of the flow channel 12 is minimized.

[0062] As combined Figures 7a to 7d As described above, the length of the fin wall 36 of the outermost fin 38 may be less than the height h of the flow channel 12. As shown by reference symbol 38C in the figure, the fin 32 may be open toward the heat exchange portion 14 of the plate 4. Figure 8 As shown, and in Figure 2 In contrast, the size of the bypass gap can be reduced when assembling and manufacturing the plate package according to the invention.

[0063] Those skilled in the art recognize that the present invention is not limited to the above examples. Those skilled in the art further recognize that modifications, combinations and variations within the scope of the appended claims are possible. In addition, variations to the disclosed embodiments may be understood and implemented by a skilled person in practicing the claimed invention by studying the drawings, the disclosure and the appended claims.

Claims

1. A method for assembling a plate pack of a plate-fin heat exchanger (1), said plate pack comprising: a plurality of flat plates (4, 4') and a plurality of fin plates (3), wherein each flat plate (4, 4') comprises peripheral flank portions (4a, 4b; 4a', 4b') located on two opposite longitudinal sides of the respective flat plate; wherein each flank portion is permanently joined to an adjacent flat plate (4'), such that a longitudinally extending flow channel (12) is formed between said adjacent flat plates (4, 4'), and wherein each flat plate (4, 4') comprises a heat exchange portion (14) having a transverse extension between said peripheral flank portions (4a, 4b; 4a', 4b'); wherein said fin plate (3) comprises a plurality of longitudinally extending fins (32) arranged in said heat exchange portion (14), said fins (32) forming parallel guiding channels (34) for a first heat exchange medium (18) and a second heat exchange medium (22) respectively in a transverse direction; and wherein said fin plate (3) and said flat plates (4, 4') are permanently attached to one another; and wherein said method comprises: i. providing a flat plate (4) comprising peripheral flank portions (4a, 4b) located on opposite longitudinal sides of said flat plate, said flank portions defining a heat exchange portion (14) of said flat plate; ii. providing a fin plate (3) having longitudinally extending fins (32), said fin plate having a transverse extension greater than the transverse extension of the heat exchange portion (14) of said flat plate (4); iii. pressing opposite sides of said fin plate (3) towards one another in said transverse direction such that said fin plate fits between said flank portions (4a, 4b) and on the heat exchange portion (14) of said flat plate; iv. placing the next flat plate (4') in the group on top of the previous fin plate (3) in the group such that at least a portion of said next flat plate (4') contacts the fins (32) of the fin plate (3) assembled in the heat exchange portion (14) of the previous flat plate (4), and such that the flank portions (4a, 4b) of the previous flat plate (4) are connected to the flank portions (4a', 4b') of said next flat plate (4'); v. repeating steps i)-iv) until the number of plates in the group reaches a target number; vi. permanently joining together said flat plates and said fin plate comprising said flank portions.

2. The method according to claim 1, wherein, in step iv), the flank portions (4a, 4b) of the flat plate (4) are connected to the flank portions (4a', 4b') of the next flat plate (4') such that they overlap in the height direction of the group.

3. The method according to any one of the preceding claims, wherein, The heat exchange portion (14) of the flat plate (4) transitions to the flank portions (4a, 4b) via rounded corner portions (44) on respective sides of the flat plate (4), and wherein in step iii), the pressing of the flank portions (4a, 4b) includes minimizing the radius (r) of the rounded corner portions (44).

4. The method according to claim 3, wherein, step iii) further includes minimizing the radius (r) such that the radius (r) is less than the height (h) of the flow channel, preferably less than 0.5h, and / or such that the radius is less than twice the thickness of the flat plate (4), preferably less than 1.1 times the thickness (d4) of the flat plate (4), and / or such that the distance (d1) between the inner surface (42) of the flank portions (4a, 4b) and the outermost portion (38) of the fin (32) closest to the flank portions (4a, 4b) is less than the height (h) of the flow channel (12) at the midpoint (MH) of the height of the flow channel, preferably less than 0.5h.

5. The method according to any one of the preceding claims, wherein, in step iii), the pressing includes adjusting a first distance (d1) measured at the midpoint (MH) of the height of the flow channel (12) between the inner surface (42) of the flank portions (4a, 4b) and the outermost portion (38) of the fin (32) closest to the flank portions (4a, 4b) such that the first distance (d1) is less than a second distance (d2) between two adjacent fins (32), or such that the first distance (d1) is less than the height (h) of the flow channel (12).

6. The method according to claim 5, wherein, the first distance (d1) is less than 0.7h, preferably less than 0.5h.

7. The method according to any one of the preceding claims, wherein, in step iii), the pressing includes adjusting a first hydraulic diameter (dh1) between the inner surface (42) of the flank portions (4a, 4b) and the outermost portion (38) of the fin (32) closest to the flank portions (4a, 4b) such that the first hydraulic diameter (dh1) is equal to or less than twice a second hydraulic diameter (dh2) between two adjacent fins measured at a point along the longitudinal extension of the fin (32) where the hydraulic diameter is minimum.

8. The method according to any one of the preceding claims, wherein, step (ii) includes providing a fin plate (3), wherein the length of the fin wall (36) of the outermost fin (38) is less than the height of the flow channel (12), and the fins are open towards the heat exchange portion (14) of the flat plate (4).

9. The method according to claim 8, wherein, the length of the fin wall (36) is less than 0.5h, or less than 0.25h.

10. The method according to any one of the preceding claims, wherein, In a step, the lateral wing portions (4a, 4b; 4a', 4b') of the adjacent flat plates (4, 4') are permanently joined to provide a plate pack (2).

11. The method according to claim 10, wherein, the permanent joining in step vi) is carried out by soldering or by means of a material joining of the heat transfer plates by applying a molten inhibitor composition to the heat transfer plates before heat bonding.

12. A plate fin heat exchanger (1) comprising a plate pack (2) including a plurality of flat plates (4, 4') and a plurality of fin plates (3), wherein each flat plate (4, 4') includes outer peripheral lateral wing portions (4a, 4b; 4a', 4b') located on two opposite longitudinal sides of the respective flat plate, and wherein each lateral wing portion is permanently joined to an adjacent flat plate (4') such that a longitudinally extending flow channel (12) is formed between the adjacent flat plates (4, 4'), and wherein each flat plate (4, 4') includes a heat exchange portion (14) having a transverse extension between the peripheral lateral wing portions (4a, 4b; 4a', 4b'), and wherein the fin plates (3) include a plurality of longitudinally extending fins (32) arranged in the heat exchange portion (14) of the flow channel (12) between the adjacent flat plates (4) and in contact with the adjacent flat plates (4), the fins (32) forming parallel guiding channels (34) for a first heat exchange medium (18) and a second heat exchange medium (22) respectively in a transverse direction, and wherein the heat exchange portion (14) of the flat plate (4) transitions to the lateral wing portion (4a, 4b) via a rounded corner portion (44) on the respective side of the flat plate (4), and wherein the lateral wing portion (4a, 4b) is pressed such that the radius (r) of the rounded corner portion (44) is minimized and less than the height (h) of the flow channel, preferably less than 0.5h, and / or such that and / or such that the radius (r) is less than twice the thickness (d4) of the flat plate (4), preferably less than 1.1 times the thickness (d4) of the flat plate (4), and / or such that a first distance (d1) between the inner surface (42) of the lateral wing and the outermost fin (38) measured at the midpoint (MH) of the height of the flow channel (12) is less than a second distance (d2) between two adjacent fins (32), and / or such that the first distance (d1) is less than the height (h) of the flow channel (12), wherein the length of the fin wall (36) of the outermost fin (38) is less than the height of the flow channel (12), and the fins (32) are open towards the heat exchange portion (14) of the flat plate (4).

13. The heat exchanger according to claim 12, wherein, The first hydraulic diameter (dh1) between the inner surface (42) of the flank portion (4a, 4b) and the outermost part (38) of the fin closest to the flank portion is equal to or less than twice the second hydraulic diameter (dh2) between two adjacent fins measured at the point along the longitudinal extension of the fin (32) where the hydraulic diameter is the smallest.

Images