Plate heat exchanger

Abstract

The present disclosure relates to a plate heat exchanger (10) comprising permanently joined plates (1) comprising a first heat transfer plate (1 ') and a second heat transfer plate (1' '). The heat transfer pattern includes ridges (36) and groove portions (38). The ridge (36) extends along a ridge line (46) and the groove portion (38) extends along a groove line (48). In the heat transfer region (34), the first heat transfer plate (1 ') is permanently joined to the second heat transfer plate (1' ') with a plurality of joints (50) along a ridge line (46) of the first heat transfer plate (1') and a groove line (48) of the second heat transfer plate (1 ''), and for each of the plurality of joints (50), the quotient between a perimeter O of the joint (50) and an area A of the joint (50) is O / A > = 2.6 mm-1.

Description

Technical Field

[0001] The invention relates to a plate heat exchanger. Background Art

[0002] WO 2011 / 162659 discloses a plate heat exchanger comprising a number of heat exchanger plates provided beside each other, which form a first plate gap and a second plate gap in an alternating order. Every other heat exchanger plate forms a main plate, and every other forms a secondary plate. Each heat exchanger plate extends in an extension plane and comprises a heat transfer area and an edge area surrounding the heat transfer area. The heat transfer area comprises corrugations of ridges and valleys, each of which extends in a longitudinal direction. The ridge has two edge surfaces, and a support surface located between the edge surfaces and having a first width transverse to the longitudinal direction. The valley has two edge surfaces, and a support surface located between the edge surfaces and having a second width transverse to the longitudinal direction. The support surface of the valley of the main plate is inclined relative to the extension plane, and the support surface of the ridge of the secondary plate is inclined relative to the extension plane.

[0003] In the plate heat exchanger of WO 2011 / 162659, the ridges and valleys of the primary plate extend across the ridges and valleys of the secondary plate. Since the supporting surfaces of the valleys and ridges are inclined relative to the extension plane, contact points with small areas are generated at the intersections of the ridges and valleys of the primary and secondary plates.

[0004] In addition to the concept of inclined bearing surfaces, WO 2011 / 162659 discloses a common arrangement in which the longitudinal directions of the ridges and valleys of adjacent plates intersect each other. Thus, many individual contact points are formed over the heat transfer area, at which the plates are durably joined to each other, for example by brazing using a copper or nickel-based brazing material.

[0005] US 4915165 discloses a plate heat exchanger, the heat exchanger plates of which have been provided by pressing with a corrugated pattern comprising ridges and valleys, the ridges and valleys of adjacent plates extending in parallel. In each plate gap, the ridges of adjacent plates abut against each other so that the opposing valleys form parallel flow paths in the plate gap. The ridges of at least some of the heat exchanger plates are provided with depressions which form thresholds in the valleys formed by the ridges on opposite sides of the plates. Thresholds of this kind are formed in the heat exchanger plates so that they create in the plate gap a flow resistance for one heat exchange medium which is significantly greater than the flow resistance created in the plate gap for another heat exchange medium.

[0006] The ridges and valleys of the individual plates of the plate heat exchanger of US 4915165 are arranged in a main direction along the heat exchanger plates, i.e. along the longitudinal extension of the plates. Although US 4915165 mentions the possibility of durably connecting the heat exchanger plates to each other by soldering or welding, the invention is discussed in the context of a plate heat exchanger provided with gaskets between adjacent heat exchanger plates of the plate heat exchanger. Therefore, the nature and placement of the joints between adjacent heat transfer plates in a soldered or welded embodiment of a plate heat exchanger are not discussed in US 4915165. Summary of the invention

[0007] It would be advantageous to achieve a plate heat exchanger with firmly connected heat transfer plates. In particular, it would be desirable to provide a plate heat exchanger comprising strong joints between the heat transfer plates on their respective heat transfer surfaces. In order to better solve one or more of these problems, a plate heat exchanger having the features defined in the independent claims is provided.

[0008] According to one aspect, a plate heat exchanger is provided, comprising a plate package of durably connected heat transfer plates. Each of a first heat transfer plate and an adjacent second heat transfer plate of the plate package comprises a first end portion, a central portion and a second end portion arranged continuously along the longitudinal axis of the respective heat transfer plate, the first end portion being provided with at least one port hole, the second end portion being provided with at least one port hole, and the central portion comprising a heat transfer area provided with a heat transfer pattern. The heat transfer pattern comprises ridges and groove portions, the top portion of the ridges extending in a first plane and the bottom portion of the groove portions extending in a second plane, the first plane and the second plane being parallel to each other and forming the outer limit of the heat transfer pattern in a direction perpendicular to the longitudinal axis. The ridges are interrupted by an intermediate section extending at a different level from the first plane, and / or the groove portions are interrupted by an intermediate section extending at a different level from the second plane. The ridges extend along a plurality of ridge lines, and the groove portions extend along a plurality of groove lines, the ridge lines being arranged alternately with the groove lines and extending in parallel. In the heat transfer area, the first heat transfer plate is durably connected to the second heat transfer plate with a plurality of joints along the ridge line of the first heat transfer plate and the groove line of the second heat transfer plate. For each of the plurality of joints, the quotient between the circumference O of the joint and the area A of the joint is O / A ≥ 2.6 mm -1 .

[0009] Since in the heat transfer region, the first heat transfer plate is durably connected to the second heat transfer plate with a plurality of joints along the ridge line of the first heat transfer plate and the groove line of the second heat transfer plate, and since for each of the plurality of joints, the quotient between the perimeter O of the joint and the area A of the joint is O / A ≥ 2.6 mm -1, therefore, the joints arranged along the ridge lines and groove lines are constructed in a particularly advantageous manner from the point of view of the strength of the joints. These strong joints are provided in the heat transfer area of ​​the first heat transfer plate and the second heat transfer plate. Thus, a plate heat exchanger with intended strength characteristics is achieved.

[0010] Since the plurality of joints between the first heat transfer plate and the second heat transfer plate in the heat transfer area extend along the ridge and groove lines, individual joints of the plurality of joints have a length along the ridge and groove lines. That is, individual joints of the plurality of joints have a length along the ridge and groove lines that is longer than a width across the ridge and groove lines. For example, individual joints of the plurality of joints may have an elliptical shape, a superelliptical shape with a convex perimeter, or a substantially rectangular shape.

[0011] The inventors have realised that the length of a joint between two durably connected heat transfer plates is more important than the area of ​​the joint. After examining a substantially circular conventional joint between heat transfer plates that has been subjected to loads, it has been seen that in a cross section of the joint, the joint is more elongated at the periphery of the joint than at the centre of the joint. Therefore, the periphery of the joint has locally been subjected to higher loads at its periphery than at its centre.

[0012] The inventors have realised that by providing an elongated joint, the length of the circumference of the joint is increased compared to a circular joint of the same area. The load is therefore distributed over the long circumference, with less load being experienced per unit length than in a circular joint. The inventors have therefore realised that by ensuring that the joint is long compared to its width (which may be defined by the quotient between the circumference O of the joint and the area A of the joint), an efficient joining of the heat transfer plates is provided. In the case of a joint of relevant size for a plate heat exchanger of common size, the quotient is O / A ≥ 2.6 mm -1 .

[0013] Compared to WO 2011 / 162659, the joint provided between two adjacent heat transfer plates in the present plate heat exchanger is longer and therefore stronger.

[0014] In WO 2011 / 162659, the joint formed between two adjacent plates provides only point-like contact points due to the intersection of ridges and valleys. In order to increase the bonding strength between two adjacent plates, it will be necessary to increase the number of contact points between the two adjacent plates. This measure requires increasing the number of valleys and ridges, which will reduce the distance between two adjacent plates and, therefore, will significantly change the flow characteristics of the heat transfer fluid through the heat exchanger.

[0015] In this context, a plate heat exchanger may alternatively also be referred to as a heat exchanger for short.

[0016] In this document, heat transfer plates may be referred to as plates. In the technical field, heat transfer plates may also be referred to as heat exchanger plates or heat exchange plates.

[0017] Each of the heat transfer plates may have a generally rectangular shape, viewed perpendicularly to the first plane and the second plane.

[0018] A major part of the heat transfer plates in the plate package, such as all the heat transfer plates, may be of the same kind as the first and second heat transfer plates.

[0019] If not all heat transfer plates are of the same kind, at least the heat transfer pattern of all heat transfer plates may be the same.

[0020] The plate heat exchanger is arranged for heat exchange between at least two fluids. The two fluids flow through the plate package on opposite sides of each of the heat transfer plates. The fluids flow through the gaps between the heat transfer plates.

[0021] At least one of the fluids flows into and out of the plate pack through port hole channels formed by at least one port hole at each of the first end portion and the second end portion and corresponding port holes in other heat transfer plates. Additional fluids may also flow into and out of the plate pack via additional port hole channels formed by port holes in the heat transfer plates. Alternatively, alternating gaps between the plates are open from the sides of the plate pack so that one of the fluids may flow through the plate pack in a direction across the longitudinal axis.

[0022] At least one port hole in the first end portion of the first and second heat transfer plates together with the port holes of the adjacent heat transfer plates forms a port hole channel extending through the plate pack perpendicularly to the longitudinal axis. Similarly, at least one port hole in the second end portion of the first and second heat transfer plates together with the port holes of the adjacent heat transfer plates forms a port hole channel extending through the plate pack perpendicularly to the longitudinal axis.

[0023] The gap formed between the first and second heat transfer plates in the plate package may be arranged to be in fluid communication with the two port hole channels discussed above. Alternatively, the gap between the first and second heat transfer plates may be arranged to be in fluid communication with two further port hole channels. The further port hole channels are formed by further port holes in the first and second end portions of the first and second heat transfer plates and the port holes of adjacent heat transfer plates in the plate package.

[0024] Another alternative may be that the gap between the first heat transfer plate and the second heat transfer plate is open from the sides of the plates. In the latter case, the port holes in the first end portion and the second end portion of the first heat transfer plate and the second heat transfer plate form a port hole channel with the adjacent heat transfer plate. The port hole channel thus formed is in fluid communication with the gap formed between the first heat transfer plate and the second heat transfer plate and the adjacent heat transfer plate.

[0025] During use of a plate heat exchanger, heat transfer between two media, such as two fluids or heat transfer fluids, occurs primarily via the heat transfer areas of the respective heat transfer plates. The number of heat transfer plates and the size and shape of the heat transfer areas of the respective plates provide a certain heat exchange capacity for a certain flow rate of the fluid flowing through the heat exchanger.

[0026] The overall shape of the heat transfer area of ​​the heat transfer plate is defined by the ridge and groove portions as discussed above. Within this overall shape, various modifications are foreseen to adapt a particular heat exchanger to a certain heat exchange capacity, such as, for example, changing the distance between the ridge and groove portions, changing the distance between the first plane and the second plane, changing the length of the intermediate section, etc.

[0027] The ridges of the first heat transfer plate and the grooves of the second heat transfer plate abut against each other in the heat transfer area along the ridge lines of the first heat transfer plate and the groove lines of the second heat transfer plate. In a corresponding manner, the ridges and grooves of the other heat transfer plates of the plate package abut against each other along the ridge lines and groove lines.

[0028] The abutment between the ridge and groove portions of adjacent heat transfer plates along the ridge and groove lines forms channels in the gap formed between the plates. In other words, the gap between the first plate and the second plate is formed by channels extending in parallel due to the abutment of the ridge and groove portions of adjacent heat transfer plates along the ridge and groove lines in the heat transfer area.

[0029] In the gap between the first heat transfer plate and the second heat transfer plate, the middle section of the ridge and the middle section of the groove portion provide for the fluid through the gap to flow between the channels formed by the abutment between the ridge and groove portions of the first heat transfer plate and the second heat transfer plate. For example, this can help the fluid to pass through the entire heat transfer area and / or accommodate flow resistance in the gap.

[0030] A ridge line may be a line along which a ridge of a heat transfer plate extends. The ridge line may be, for example, straight or have a sawtooth shape, such as a zigzag shape. The ridge line may be interrupted by an intermediate section. The ridge line extends parallel to the heat transfer area of ​​the heat transfer plate. Similarly, a groove line may be a line along which a groove portion of a heat transfer plate extends. The groove line may be, for example, straight or have a sawtooth shape, such as a zigzag shape. The groove line may be interrupted by an intermediate section. The groove line extends parallel to the heat transfer area of ​​the heat transfer plate.

[0031] In the heat transfer area of ​​adjacent heat transfer plates, the ridges of one plate abut against the groove portions of the adjacent plate along corresponding ridge and groove lines. That is, in the heat transfer area, the ridge and groove portions of the adjacent plates do not cross each other.

[0032] The ridge and groove portions of the heat transfer plate together with the corresponding intermediate sections of the ridge and groove portions form a heat transfer pattern. The heat transfer pattern can provide a desired flow resistance for the heat transfer fluid and / or can promote turbulence in the heat transfer fluid and thus can provide a certain heat transfer capacity for the associated plate heat exchanger during use of the plate heat exchanger.

[0033] The 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. For example, as discussed in WO 2013144211, such a joining method may be one of brazing using an added brazing material in the form of a foil, paste or powder, for example comprising copper or nickel, or joining via the material of the heat transfer plates by application of a melting inhibitor composition applied to the heat transfer plates prior to heating.

[0034] According to an embodiment, the first heat transfer plate and the second heat transfer plate may be of the same kind. In the plate package, the second heat transfer plate may be rotated 180 degrees relative to the first heat transfer plate parallel to the first plane and the second plane. In this way, at least a part of the plate package may include only one kind of heat transfer plates. This facilitates the manufacture of the plates included in the plate package.

[0035] The remaining heat transfer plates of the plate package may be arranged adjacent to each other in the same manner, ie rotated by 180 degrees parallel to the first plane and the second plane relative to adjacent heat transfer plates.

[0036] According to an embodiment, a portion of each intermediate section of the ridges extends at the level of the second plane, and / or wherein a portion of each intermediate section of the groove portions extends at the level of the first plane. In this way, an opening having a height of the distance between the first plane and the second plane may be formed through the intermediate sections. The opening fluidly connects adjacent channels formed by adjoining ridge and groove portions within a gap between two adjacent heat transfer plates, such as between a first heat transfer plate and a second heat transfer plate.

[0037] According to an embodiment, the top portion or ridge in the first plane may be wider than the bottom portion of the groove portion in the second plane, or the bottom portion of the groove portion in the second plane may be wider than the top portion of the ridge in the first plane. In this way, a narrow width of a joint in a plurality of joints may be achieved. Furthermore, in this way it may be ensured that the ridge of one plate will abut against the groove portion of an adjacent plate. Thus, even in the case of a certain inaccuracy in the lateral positioning of the ridge and groove portions of the heat transfer patterns of the adjacent plates, abutment is achieved.

[0038] According to an embodiment, in the first end portion, the first heat transfer plate and the second heat transfer plate may be connected by a first series of joints arranged at least partially circumferentially around at least one port hole of the first end portion. In the second end portion, the first heat transfer plate and the second heat transfer plate may be connected by a second series of joints arranged at least partially circumferentially around at least one port hole of the second end portion. The heat transfer pattern of the central portion may be arranged adjacent to and extending between the first series of joints and the second series of joints. In this way, a large part of the heat transfer plate may be formed by the central portion and, therefore, a large part of the heat transfer plate may form a heat transfer area. Therefore, the heat transfer plate may be used to achieve an optimal heat transfer.

[0039] According to an embodiment, the ridge and groove lines may extend along a straight line, and the ridge and groove lines may extend at one or more angles in the range of 0-90 degrees to the longitudinal axis. In this way, the ridge and groove portions may extend at a smaller or lesser angle to the general direction of at least one of the heat transfer fluids intended to flow through the plate heat exchanger substantially parallel to the longitudinal axis. Thus, the flow resistance for the at least one heat transfer fluid may be adapted in particular by the angle of the ridge and groove lines to the longitudinal axis.

[0040] Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Various aspects and / or embodiments of the present invention including its particular features and advantages will be readily understood from the exemplary embodiments discussed in the following detailed description and accompanying drawings, in which:

[0042] Figure 1a and Figure 1b shows a plate heat exchanger according to an embodiment,

[0043] Figure 2a and 2b shows a heat transfer plate according to an embodiment,

[0044] Figure 3a and 3b A cross-sectional view and a perspective view showing three heat transfer plates of a plate package of a plate heat exchanger according to an embodiment,

[0045] Figure 4 The cross-sectional shape of the joint is schematically shown.

[0046] Figure 5a shows a top view of a heat transfer plate according to an embodiment,

[0047] Figure 5b A cross-sectional view and a perspective view of two heat transfer plates are shown, and

[0048] Figure 6 Shown is a cross section through a first heat transfer plate and a second heat transfer plate according to an embodiment. DETAILED DESCRIPTION

[0049] Aspects and / or embodiments of the present invention will now be described more fully. Throughout the text, similar numbers represent similar elements. For the sake of simplicity and / or clarity, well-known functions or configurations will not necessarily be described in detail.

[0050] Figure 1a and 1b A plate heat exchanger 10 according to an embodiment is shown.

[0051] The plate heat exchanger 10 comprises a plurality of heat transfer plates 1 according to any of the embodiments discussed herein, a first end plate 2 provided beside the outermost heat transfer plate among the heat transfer plates 1, and a second end plate 3 provided beside the opposite outermost heat transfer plate 1. The second end plate 3 is Figure 1a , since it is arranged within the flange 7 of the associated outermost heat transfer plate 1. Figure 1a The longitudinal axis LA extends along the length of the plate 1 .

[0052] The heat transfer plates 1 are produced by forming of metal sheets and are arranged beside each other. The first end plate 2, the second end plate 3 and the heat transfer plates 1 are durably joined to each other to form a plate package 4. Each heat transfer plate 1 comprises a flange 7 extending around the heat transfer plate 1. The flanges 7 of adjacent plates 1 may overlap and are durably joined to each other.

[0053] See for example Figure 3a and 3b In the plate group 4, adjacent heat transfer plates 1 define therebetween first plate interspaces for the first medium and second plate interspaces for the second medium. The first medium and the second medium may be any suitable fluids between which heat will be transferred during use of the plate heat exchanger 10.

[0054] The plate heat exchanger 10 of the disclosed embodiment has four port hole channels S1, S2, S3 and S4 formed by port holes in individual plates 1. Port hole channel S1 is connected to the connecting pipe 11 and communicates with the first plate gap. Port hole channel S2 is connected to the connecting pipe 12 and communicates with the first plate gap. Port hole channel S3 is connected to the connecting pipe 13 and communicates with the second plate gap, and port hole channel S4 is connected to the connecting pipe 14 and communicates with the second plate gap.

[0055] It is noted that the plate heat exchanger may have another number of port hole channels than the disclosed number of port hole channels provided by a corresponding number of port holes of the heat transfer plate 1 , such as 2, 3, 5, 6, 7 or 8 port hole channels.

[0056] A connecting tube may be provided extending from the first end plate 2 (as disclosed) and / or from the second end plate 3 in fluid communication with the port hole channel.

[0057] Figure 2a and 2b A heat transfer plate 1 according to an embodiment is shown. Figure 2a shows a top view of the entire plate 1, and Figure 2b A top view of a portion of the plate 1 is shown. For simplicity, Figure 2a and 2b The circumferential flange portion of the plate 1 is omitted.

[0058] Plate 1 and Figure 1a and 1b The plates 1 of the plate heat exchanger 10 shown in FIG. 1 are of similar type. Figure 2a and 2b A plate heat exchanger is assembled from a plurality of plates 1 shown in FIG.

[0059] The heat transfer plate 1 has a rectangular shape with two long side edges 16 and two short side edges 18. A longitudinal axis LA extends parallel to the long side edges 16 and transversely to the short side edges 18.

[0060] In a plate heat exchanger, a heat transfer plate 1 is durably joined to adjacent heat transfer plates of the same or similar kind to form a plate package.

[0061] A first heat transfer plate 1 and an adjacent second heat transfer plate 1 of a plate package may be of the same kind. In the plate package, the second heat transfer plate may be rotated 180 degrees relative to the first heat transfer plate in a plane comprising the longitudinal axis LA and the long side edge 16 and the two short side edges 18. In this way, a first plate 1, a second plate 1 and further heat transfer plates 1 of the same kind may be used to form at least a major part of a plate package.

[0062] Each of the heat transfer plate 1 and the further heat transfer plates in the plate package comprises a first end portion 20, a central portion 22 and a second end portion 24 arranged consecutively along the longitudinal axis LA of the respective heat transfer plate 1. The first end portion 20 is provided with at least one port hole 26, 32 and the second end portion 24 is provided with at least one port hole 28, 30.

[0063] In these embodiments, each of the first end portion 20 and the second end portion 24 is provided with two port holes 26 - 32 .

[0064] The central portion 22 comprises a heat transfer area 34 provided with a heat transfer pattern. The heat transfer area 34 forms an area where the main part of the heat transfer between the first medium and the second medium on opposite sides of the plate 1 takes place during use of the plate heat exchanger.

[0065] like Figure 2b As exemplified at the first end portion 20 in FIG. 1 , in the respective first end portion 20 and the second end portion 24, each port hole 26-32 is surrounded by a port hole area 35. In a known manner, the port hole area 35 is shaped such that within the heat exchanger and along the respective port hole channels, the heat transfer plates 1 abut against each other alternately in a sealing manner and in a through flow passage defining entry and exit into the respective gaps between the plates 1.

[0066] More specifically, in the respective port hole areas 35 of the first end portion 20 and the second end portion 24, the heat transfer plates 1 are provided with protrusions and depressions configured to abut against corresponding protrusions and depressions of adjacent heat transfer plates 1. The port holes in the respective port hole areas 35 of the respective heat transfer plates 1 may be cut to different diameters or may be cut to have different shapes in order to provide alternating open and sealed gaps between the plates 1 along the respective port hole channels.

[0067] A series of joints are arranged where these protrusions and depressions abut against each other. The joints are arranged at least partially circumferentially around the port holes 26-32 of the end portions 20,24.

[0068] Again, in a known manner and mentioned as an example, the heat transfer plates 1 may be of the same kind. Within the plate pack 4, the individual heat transfer plates 1 are stacked, wherein every other heat transfer plate 1 is rotated 180 degrees around an axis perpendicular to a plane comprising the long side edges 16 and the short side edges 18 of the plates 1. Thus, abutment and sealing against each other in the port hole areas 35 may be achieved to define through-flow passages entering and leaving the respective gaps between the plates 1. Alternatively, other known ways of achieving alternating sealing and through-flow may be used, for example by providing more than one kind of heat transfer plates 1 with correspondingly shaped port hole areas.

[0069] The heat transfer area 34 of the central portion 22 includes a heat transfer pattern of alternating ridge 36 and groove portions 38 extending parallel to each other. Top portions of the ridges 36 extend in a first plane and bottom portions of the groove portions 38 extend in a second plane.

[0070] The ridges 36 are interrupted by intermediate segments 44 extending at a different level than the first plane. Additionally or alternatively, the groove portions 38 are interrupted by corresponding intermediate segments (not shown) extending at a different level than the second plane. More specifically, the intermediate segments 44 form portions of the heat transfer pattern that interrupt the ridges 36 and / or groove portions 38, respectively.

[0071] The ridges 36 extend along a plurality of ridge lines 46 (indicated by dashed double dotted lines), and the groove portions 38 extend along a plurality of groove lines 48 (indicated by dashed lines). The ridge lines 46 and the groove lines 48 are alternately arranged in the heat transfer region 34 and extend in parallel.

[0072] refer to Figure 3a and 3b Looking further below, the arrangement of the ridge 36 and groove portions 38 of two adjacent plates 1 is concerned and the arrangement of the top portion of the ridge 36 extending in a first plane and the bottom portion of the groove portion 38 extending in a second plane.

[0073] According to some embodiments, such as the embodiment shown, and as Figure 2b As clearly shown in the figure, the heat transfer pattern of the central portion 22 is arranged in close proximity to the port hole area 35, i.e. the heat transfer pattern extends up to the projections and depressions of the respective port hole areas 35 of the first end portion 20 and the second end portion 24 of the heat transfer plate 1. Thus, a large part of the heat transfer plate 1 may be formed by the heat transfer area 34 comprising the heat transfer pattern.

[0074] More specifically, according to an embodiment, in the first end portion 20, the first and second heat transfer plates 1 may be joined by a first series of joints arranged at least partially circumferentially around at least one port hole 26, 32 of the first end portion 20, and in the second end portion 24, the first and second heat transfer plates 1 may be joined by a second series of joints arranged at least partially circumferentially around at least one port hole 28, 30 of the second end portion 24. The heat transfer pattern of the central portion 22 may be arranged adjacent to and extend between the first and second series of joints, which are arranged at least partially circumferentially around at least one port hole 26-32 of the first and second end portions 20, 24, respectively.

[0075] In these embodiments, the ridge lines 46 and the groove lines 48 extend along straight lines. The ridge lines 46 and the groove lines 48 extend at one or more angles α in the range of 0-90 degrees with the longitudinal axis LA. Figure 2b , angle α is shown to be approximately 45 degrees.

[0076] According to some embodiments, the ridge lines 46 and the groove lines 48 extend along straight lines, wherein the ridge lines 46 and the groove lines 48 extend at one or more angles a in the range of >0-80 degrees with the longitudinal axis LA.

[0077] The size of the angle α will affect the flow resistance of at least one heat transfer fluid through the gaps between the plates 1. The angle α may be selected to provide a desired flow resistance in a plate heat exchanger, wherein the plates 1 form a plate pack.

[0078] Figure 3a and 3b A cross-sectional view and a perspective view of three heat transfer plates 1 of a plate package 4 of a plate heat exchanger according to an embodiment are shown. The cross section extends along an edge portion of the plate package 4 so that the gaps 6 between the plates 1 are Figure 3a and 3b Shown in. Figure 3b Shows Figure 3a A closer view of the cross section.

[0079] Figure 3a and 3b The plate 1 shown in FIG. Figure 2a and 2b The plates 1 shown in are of the same type. Figure 3a and 3b The plate heat exchanger with the plates 1 may be of a similar kind to the plate heat exchanger 10 discussed above with reference to Figure 1. Therefore, reference is also made to Figures 1-2b in the following.

[0080] The plate package 4 of a plate heat exchanger comprises a plurality of durably connected heat transfer plates 1 .

[0081] As mentioned above Figure 2a and 2b As discussed, each of the first heat transfer plate 1' and the adjacent second heat transfer plate 1" of the plate package 4 comprises a first end portion 20, a central portion 22, and a second end portion 24. Note that in Figure 3a and 3b In the embodiment, a second plate 1" is stacked on top of a first plate 1'.

[0082] Again, the first end portion is provided with at least one port hole, and the second end portion ( Figure 3a ) is provided with at least one port hole, and the central portion includes a heat transfer area 34 provided with a heat transfer pattern.

[0083] Again, the heat transfer pattern includes ridges 36 and groove portions 38. The top portion of the ridges 36 extends in a first plane 40 (indicated by dashed lines) and the bottom portion of the groove portions 38 extends in a second plane 42 (indicated by dot-dash lines). The first plane 40 and the second plane 42 extend parallel to each other and form the outer limit of the heat transfer pattern in a direction perpendicular to the longitudinal axis LA.

[0084] In the heat transfer area 34, the first heat transfer plate 1' is durably joined to the second heat transfer plate 1" with a plurality of joints along ridges 36 of the first heat transfer plate 1' and groove portions 38 of the second heat transfer plate 1". In a similar manner, further heat transfer plates are joined along ridge and groove portions of adjacent heat transfer plates 1 running through the plate package 4. Thus, within the plate package 4, adjacent heat transfer plates 1 define between them first plate interspaces 6 for the first medium and second plate interspaces 6' for the second medium.

[0085] The gaps 6 , 6 ′ thus formed are constituted by channels 39 extending between the first plane 40 and the second plane 42 , the channels 39 being formed between the joined ridge 36 and groove portions 38 of adjacent heat transfer plates 1 .

[0086] The ridges 36 are interrupted by intermediate sections 44 that extend at a different level than the first plane 40 , and / or the groove sections 38 are interrupted by intermediate sections that extend at a different level than the second plane 42 .

[0087] Due to the intermediate section 44 , during use of the heat exchanger, a fluid passing along the interspace 6 , 6 ′ between two plates 1 can flow between the channels 39 .

[0088] A portion of each intermediate section 44 of the ridges 36 may extend at the level of the second plane 42 , and / or a portion of each intermediate section of the groove portions 38 may extend at the level of the first plane 40 .

[0089] The ridges 36 are arranged along a plurality of ridge lines 46 (at Figure 3a The groove portion 38 extends along a plurality of groove lines 48 (indicated by dashed double dotted lines in FIG. Figure 3a The ridge lines 46 and the groove lines 48 are arranged alternately and extend in parallel.

[0090] In a corresponding manner, the ridge and groove portions of the remaining heat transfer plates 1 of the plate package 4 also extend along the ridge and groove lines.

[0091] exist Figure 3a and 3b 3 and 4. The ridges 36 and groove portions 38, the first and second planes 40 and 42, and the ridge lines 46 and groove lines 48 for the second heat transfer plate 1" are shown. The first heat transfer plate 1' and each of the remaining heat transfer plates 1 of the plate package 4 have corresponding ridge and groove portions, first and second planes, and ridge lines and groove lines.

[0092] In the heat transfer area 34, the first heat transfer plate 1' is durably joined to the second heat transfer plate 1" with a plurality of joints along ridge lines 46 of the first heat transfer plate 1' and groove lines 48 of the second heat transfer plate 1". That is, the ridges 36 of the first plate 1' are joined to the groove portions 38 of the second plate 1".

[0093] For each of the plurality of joints, the quotient between the perimeter O of the joint and the area A of the joint is O / A ≥ 2.6 mm -1 .

[0094] As initially discussed, it has been found that with a quotient O / A ≥ 2.6 mm -1 The joint provides a strong joint and thus a strong bond between the heat transfer plates 1 in the plate package 4 in its heat transfer area 34 .

[0095] Because each of the plurality of joints extends along ridge line 46 and groove line 48, individual ones of the plurality of joints have a length along ridge line 46 and groove line 48. Furthermore, individual ones of the plurality of joints have a length along the ridge line and groove line that is longer than the width across the ridge line and groove line. Figure 4 See further below.

[0096] According to an embodiment, the durably joined heat transfer plates 1 may be joined by a joint including at least 50 wt % of a metal of the same kind as the metal of the heat transfer plates 1. In this way, in the method for joining the heat transfer plates 1, a melting inhibitor composition may be used to reduce the melting temperature of the metal of the heat transfer plates to form the joint.

[0097] With O / A ≥ 2.6mm -1 The joint as defined herein lends itself well to providing a strong bond between the heat transfer plates 1 , wherein the joint comprises at least 50 wt % of a metal of the same kind as the metal of the heat transfer plates 1 .

[0098] The joint may comprise at least 85 wt % of the same kind of metal as the metal of the heat transfer plate 1 , such as up to 100 wt % of the same kind of metal as the metal of the heat transfer plate 1 .

[0099] For example, as discussed in WO 2013144211, a method for joining a first heat transfer plate 1 ' made of metal with a second heat transfer plate 1 "made of metal may be used to join the heat transfer plates 1. The metal has a solidus temperature above 1100°C. The method comprises:

[0100] - applying a melting inhibitor composition comprising boron (B), or a combination of boron (B) and silicon (Si) on a surface portion of the first heat transfer plate 1 ', and

[0101] - bringing the second heat transfer plate 1 ″ into contact with the melt inhibitor composition at contact points on said surface.

[0102] The first heat transfer plate 1' and the second heat transfer plate 1" are heated together with other similarly prepared plates of the plate heat exchanger to a suitable temperature below the solidus temperature which causes the metal of at least the first heat transfer plate 1' to melt at the surface portions to which the melting inhibitor composition has been applied. When the plates cool, the molten metal solidifies and durably joins the heat transfer plates 1.

[0103] According to an embodiment, in the heat transfer area 34 the first heat transfer plate 1 ' may be durably joined to the second heat transfer plate 1 "only along ridge lines 46 of the first heat transfer plate 1 ' and groove lines 48 of the second heat transfer plate 1 ". In this way, no further joints may be provided in the heat transfer area 34 of the respective first heat transfer plate 1 ' and second heat transfer plate 1 ".

[0104] Will Figure 3a and 3b Turning it upside down would show an embodiment of the plate set 4 where the ridges 36 form groove portions, and thus the groove portions 38 form ridges. Such an embodiment includes groove portions interrupted by intermediate sections 44, similar to the intermediate sections 44 in the ridges 36 discussed above.

[0105] Figure 4 The cross-sectional shape of one of the joints 50 along the ridge line 46 of the first heat transfer plate 1' and the groove line 48 of the second heat transfer plate 1" is schematically shown, as described above with reference to Figure 3a and 3b Therefore, in the following, reference is also made to Figure 3a and 3b .

[0106] Figure 4 The cross-section of the joint 50 shown in FIG. 5 is viewed in a plane parallel to one of the first plane 40 and the second plane 42 .

[0107] According to an embodiment, each joint 50 of the plurality of joints has a length L along the ridge line 46 of the first heat transfer plate 1' and the groove line 48 of the second heat transfer plate 1", which is longer than a width W of each joint 50 across the ridge line 46 of the first heat transfer plate 1' and the groove line 48 of the second heat transfer plate 1". In this way, it is possible to provide O / A ≥ 2.6 mm in the joint 50 of suitable shape. -1 , for commercially produced plate heat exchangers.

[0108] Such shapes may include rectangular, substantially rectangular, elliptical (non-circular), and super-elliptical shapes with a convex perimeter.

[0109] According to an embodiment, each of the plurality of joints may have a width W across the ridge line 46 of the first heat transfer plate 1' and the groove line 48 of the second heat transfer plate 1", the width W being in the range of 0.4≤W≤0.8mm. In this way, it is possible to provide O / A≥2.6mm in the joint 50. -1 The joint 50 is suitable for formation into a plate heat exchanger for commercial production, and wherein the thermal performance of such a plate heat exchanger is provided for efficient heat transfer between two heat transfer fluids.

[0110] In the illustrated embodiment, the joint 50 has a rectangular cross-section with rounded corners, i.e., the cross-section of the joint 50 is substantially rectangular and may be approximated as a rectangle having a length L along the associated ridge 36 and adjacent groove portion 38 and a width W transverse to the ridge 36 and groove portion 38.

[0111] According to these embodiments, the perimeter O is calculated as follows:

[0112] O = 2x L + 2x W, and

[0113] The area A is calculated as follows:

[0114] A=L×W.

[0115] In connection with the dimensions of the joints of heat exchangers with permanently connected heat transfer plates 1, the quotient O / A ≥ 2.6 mm -1 , in order to provide a strong joint.

[0116] For example, for a connector 50 size having a length L in the range of 5-20 mm and a width W in the range of 0.4-0.8 mm, the quotient O / A may be 2.6 mm. -1 ≤O / A≤5.4mm -1 within the range.

[0117] Mentioned as just 4 examples, the joint 50 may have the following dimensions, providing the following quotients:

[0118] L = 5 mm, W = 0.4 mm, and O / A = 5.4 mm -1 ;

[0119] L = 10 mm, W = 0.5 mm, and O / A = 4.2 mm -1 ;

[0120] L = 10 mm, W = 0.8 mm, and O / A = 2.7 mm -1 ;

[0121] L = 20 mm, W = 0.8 mm, and O / A = 2.6 mm -1 .

[0122] In comparison, a commonly sized circular joint for a prior art plate heat exchanger having a diameter of 2.5 mm provides O / A = 1.6 mm -1 , and the joint with a diameter of 5 mm provides O / A = 0.8 mm -1 .

[0123] Note that for circular connectors, the O / A ≥ 2.6 mm -1 , the joints must have a diameter smaller than 0.65 mm, which is not feasible in normal sized plate heat exchangers.

[0124] As Figure 4 As an alternative to the rectangular or substantially rectangular shaped joint 50 shown in the drawings, a joint having, for example, an elliptical (non-circular) or super-elliptical shape with a convex perimeter may be used, having a length L along the ridge lines 46 and groove lines 48 that is longer than a width W across the ridge lines 46 and groove lines 48.

[0125] And for this type of joint embodiment, the quotient O / A ≥ 2.6 mm -1 Robust connections are available for plate heat exchangers of relevant sizes.

[0126] Figure 5a shows a top view of a heat transfer plate 1 according to an embodiment, and Figure 5b A cross-sectional view and a perspective view of a first heat transfer plate 1' and a second heat transfer plate 1" of a plate pack of a plate heat exchanger according to an embodiment are shown. The cross section extends along an edge portion of the plate pack so that the gaps 6 between the plates 1 are shown. These embodiments are similar to those of FIGS. 1 to 3. Figure 4 Therefore, the following will mainly discuss the differences.

[0127] Again, each of the heat transfer plates 1, 1', 1" comprises a heat transfer pattern comprising ridges 36 and groove portions 38. The top portions of the ridges 36 extend in a first plane and the bottom portions of the groove portions 38 extend in a second plane. The ridges 36 extend along a plurality of ridge lines 46 and the groove portions 38 extend along a plurality of groove lines 48, which are alternately arranged and extend in parallel.

[0128] According to these embodiments, the ridge lines 46 and the groove lines 48 extend along sawtooth lines.

[0129] like Figure 4 As indicated in FIG. 1 a, the sawtooth lines 46, 48 may meander parallel to the longitudinal axis LA. Alternatively, the sawtooth lines 46, 48 may intersect the longitudinal axis LA.

[0130] Again, the ridge 36 is interrupted by an intermediate section 44 extending at a different level from the first plane. Additionally or alternatively, the groove portion 38 is interrupted by a corresponding intermediate section (not shown) extending at a different level from the second plane.

[0131] According to these embodiments, the middle section 44 of the ridge 36 and / or the middle section of the groove portion 38 is arranged at the portion where the sawtooth lines change direction.

[0132] Figure 6 1 to 5 b. A cross section through a first heat transfer plate 1 ' and a second heat transfer plate 1 "according to an embodiment is shown. The heat transfer plates 1 ', 1 "may be heat transfer plates of a plate package included in any of the plate heat exchangers discussed above with reference to FIGS. 1 to 5 b. Therefore, in the following, reference is also made to FIGS. 1 to 5 b. Figure 5b .

[0133] Again, each of the first heat transfer plate 1 ′ and the second heat transfer plate 1 ″ comprises a heat transfer pattern comprising ridges 36 and groove portions 38 . Top portions of the ridges 36 extend in a first plane 40 and bottom portions of the groove portions 38 extend in a second plane 42 .

[0134] According to these embodiments, a bottom portion of the groove portion 38 in the second plane 42 is wider than a top portion of the ridge 36 in the first plane 40 .

[0135] According to an alternative embodiment, the Figure 6 Shown upside down, a top portion of a ridge in a first plane may be wider than a bottom portion of a groove portion in a second plane.

[0136] In these embodiments, due to the wide bottom portion or the wide top portion, it is ensured that the ridge 36 of the first plate 1' and the groove portion 48 of the second plate 1" abut against each other and thus it is ensured that the joint 50 between the ridge 36 and the groove portion 38 is provided throughout the plate set. Moreover, due to the not too wide top portion or the not too wide bottom portion, it is ensured that the joint 50 has a narrow width W.

[0137] It is to be understood that the foregoing illustrates various exemplary embodiments, and the present invention is limited only by the appended claims. Those skilled in the art will recognize that the exemplary embodiments may be modified, and different features of the exemplary embodiments may be combined to produce embodiments other than those described herein, without departing from the scope of the present invention as defined by the appended claims.

Claims

1. A plate heat exchanger (10) comprising a plate package (4) of durably connected heat transfer plates (1), wherein Each of a first heat transfer plate (1') and an adjacent second heat transfer plate (1") of the plate set (4) comprises a first end portion (20), a central portion (22) and a second end portion (24) arranged successively along a longitudinal axis (LA) of the respective heat transfer plate (1), the first end portion (20) being provided with at least one port hole (26, 32), the second end portion (24) being provided with at least one port hole (28, 30), and the central portion (22) comprising a heat transfer area (34) provided with a heat transfer pattern, wherein The heat transfer pattern comprises ridges (36) and groove portions (38), the top portions of the ridges (36) extending in a first plane (40) and the bottom portions of the groove portions (38) extending in a second plane (42), the first plane (40) and the second plane (42) being parallel to each other and forming the outer limit of the heat transfer pattern in a direction perpendicular to the longitudinal axis (LA), wherein The ridge (36) is interrupted by an intermediate section (44) extending at a different level than the first plane (40), and / or the groove portion (38) is interrupted by an intermediate section extending at a different level than the second plane (42), and wherein The ridges (36) extend along a plurality of ridge lines (46), and the groove portions (38) extend along a plurality of groove lines (48), the ridge lines (46) and the groove lines (48) being arranged alternately and extending in parallel, Features In the heat transfer area (34), the first heat transfer plate (1') is durably connected to the second heat transfer plate (1") with a plurality of joints (50) along ridge lines (46) of the first heat transfer plate (1') and groove lines (48) of the second heat transfer plate (1"), and wherein For each joint (50) in the plurality of joints (50), the quotient between the perimeter O of the joint (50) and the area A of the joint (50) is O / A ≥ 2.6 mm -1 .

2. The plate heat exchanger (10) according to claim 1, wherein: Each of the plurality of joints (50) has a length L along the ridge line (46) of the first heat transfer plate (1') and the groove line (48) of the second heat transfer plate (1"), the length L being longer than a width W of each of the joints (50) across the ridge line (46) of the first heat transfer plate (1') and the groove line (48) of the second heat transfer plate (1") 3. The plate heat exchanger (10) according to claim 1 or claim 2, wherein: Each joint (50) of the plurality of joints (50) has a width W across a ridge line (46) of the first heat transfer plate (1') and a groove line (48) of the second heat transfer plate (1"), the width W being in the range of 0.4≤W≤0.8 mm.

4. A plate heat exchanger (10) according to any one of the preceding claims, wherein: In the heat transfer area (34), the first heat transfer plate (1') is durably joined to the second heat transfer plate (1") only along ridge lines (46) of the first heat transfer plate (1') and groove lines (48) of the second heat transfer plate (1").

5. A plate heat exchanger (10) according to any one of the preceding claims, wherein: The first heat transfer plate (1') and the second heat transfer plate (1") are of the same kind, and wherein in the plate group (4), the second heat transfer plate (1") is rotated 180 degrees relative to the first heat transfer plate (1') parallel to the first plane and the second plane.

6. A plate heat exchanger (10) according to any one of the preceding claims, wherein: A portion of each intermediate section (44) of the ridge (36) extends at the level of the second plane (42), and / or a portion of each intermediate section of the groove portion (38) extends at the level of the first plane (40).

7. A plate heat exchanger (10) according to any one of the preceding claims, wherein: A top portion of the ridge (36) in the first plane (40) is wider than a bottom portion of the groove portion (38) in the second plane (42), or a bottom portion of the groove portion (38) in the second plane (42) is wider than a top portion of the ridge (36) in the first plane (40).

8. A plate heat exchanger (10) according to any one of the preceding claims, wherein: In the first end portion (20), the first heat transfer plate (1') and the second heat transfer plate (1") are connected by a first series of joints arranged at least partially circumferentially around at least one port hole (26, 32) of the first end portion (20), wherein In the second end portion (24), the first heat transfer plate (1') and the second heat transfer plate (1") are connected by a second series of joints arranged at least partially circumferentially around at least one port hole (28, 30) of the second end portion (42), and wherein The heat transfer pattern of the central portion (22) is arranged adjacent to and extends between the first series of joints and the second series of joints.

9. A plate heat exchanger (10) according to any one of the preceding claims, wherein: The ridge lines (46) and the groove lines (48) extend along straight lines, and wherein the ridge lines (46) and the groove lines (48) extend at one or more angles (α) in the range of 0-90 degrees to the longitudinal axis (LA).

10. The plate heat exchanger (10) according to any one of claims 1 to 8, wherein: The ridge lines (46) and the groove lines (48) extend along sawtooth lines.

11. The plate heat exchanger (10) according to claim 10, wherein: The middle section (44) of the ridge (36) and / or the middle section of the groove portion (38) are arranged at the portion where the sawtooth lines change direction.

12. A plate heat exchanger (10) according to any one of the preceding claims, wherein: The durably joined heat transfer plates (1) are joined by means of a joint (50) comprising at least 50 wt % of a metal of the same type as the metal of the heat transfer plates (1).

Images