Plate heat exchanger and heat pump circuit

Abstract

The disclosure concerns a plate heat exchanger (10) comprising permanently joined first and second heat transfer plates (1', 1'') provided with a first, a second, a third, and a fourth porthole. A set of first plate interspaces (36) for a first fluid and a set of second plate interspaces (38) for a second fluid are formed between the first and second plates (1', 1''). Third portholes (32) of adjoining plates (1', 1'') form a porthole channel. The first plate interspaces (36) are arranged in fluid communication with the porthole channel. A plate pattern is configured to prevent fluid flow between the first plate interspaces (36) and the porthole channel in a direction in parallel with a longitudinal axis (LA) of the plate (1', 1'') and to guide fluid flow between the first plate interspaces (36) and the porthole channel in a direction perpendicularly to the longitudinal axis (LA).

Description

[0001] Plate Heat Exchanger and Heat Pump Circuit

[0002] TECHNICAL FIELD

[0003] The invention relates to a plate heat exchanger and to a heat pump circuit.

[0004] BACKGROUND

[0005] A plate heat exchanger defines two sets of plate interspaces between heat transfer plates of the plate heat exchanger. During use of the plate heat exchanger, one of two fluids flows through one set of alternate plate interspaces for heat exchange with the other of the two fluids, which flows through the other set of alternate plate interspaces. In order to ensure efficient use of the plate heat exchanger, from port channels formed by portholes in the heat transfer plates, ideally, the fluids are distributed within an entire plate interspace.

[0006] In a heat pump circuit, a first fluid in the form of a refrigerant undergoes two phase changes, from fluid phase to gaseous phase in an evaporator and from gaseous phase to fluid phase in a condenser. In the evaporator, a second fluid is cooled by the evaporating refrigerant. In the condenser, a third fluid is heated by the condensing refrigerant.

[0007] One or both of the evaporator and the condenser in a heat pump circuit may be formed by a plate heat exchanger.

[0008] In a plate heat exchanger wherein a first fluid undergoes a phase change in one set of plate interspaces, distribution of the first fluid within the relevant plate interspaces may pose a particular challenge.

[0009] US 10,907,906 B2 discloses in a plate heat exchanger, a bypass passage and a main passage upstream of first passages and second passages between adjacent ones of first heat transfer plates and second heat transfer plates. The bypass passage allows first fluid flowing from an inflow port of the first fluid or second fluid flowing from an inflow port of the second fluid to pass a side farther than a corresponding one of adjacent holes while spreading in a vertical direction in a front view and then flow into an inner fin or a corrugated heat transfer surface. The main passage allows the first fluid flowing from the inflow port of the first fluid or the second fluid flowing from the inflow port of the second fluid to directly flow toward the inner fin or the corrugated heat transfer surface without routing through the bypass passage. A flat space is formed around an entire circumference of each of the adjacent holes, between a circumferential wall and the inner fin or the corrugated heat transfer surface.

[0010] WO 94 / 14021 discloses an evaporator in the form of a plate heat exchanger for a refrigerant circuit. The plate heat exchanger has an assembly of plates defining and separating alternate passages for the flow of a refrigerant and of a heat-exchange fluid. Aligned holes in the plates provide inlet and outlet channels for the refrigerant and the heat-exchange fluid to / from the respective passages. A refrigerant distribution tube is located in the refrigerant inlet channel. The tube has outlet apertures which direct refrigerant into the refrigerant passage. Further, so-called blanking members in the form of C-shaped washers, or a tube having a slot, blank off part of the opening from the refrigerant inlet channel into each refrigerant passage to confine the refrigerant flow from the apertures to a predetermined path towards the plate centreline to ensure even refrigerant distribution.

[0011] SUMMARY

[0012] It would be advantageous to provide an efficient plate heat exchanger adapted for use with a phase changing fluid. In particular, it would be desirable to enable distribution of a heat transfer fluid over a width of a heat transfer plate in an effective manner. To better address one or more of these concerns, one or more of a plate heat exchanger and / or a heat pump circuit having the features defined in one or more of the independent claims is provided.

[0013] According to an aspect of the invention, there is provided a plate heat exchanger comprising a plate package of permanently joined heat transfer plates. Each of alternatingly arranged first heat transfer plates and adjoining second heat transfer plates of the plate package comprises a first end portion, a centre portion, and a second end portion arranged in succession along a longitudinal axis of the respective heat transfer plate, the first end portion being provided with a first porthole and a fourth porthole, the second end portion being provided with a second porthole and a third porthole, and the centre portion comprising a main heat transfer area. The heat transfer plates are provided with a plate pattern of protrusions and recesses. A set of first plate interspaces for a first fluid and a set of second plate interspaces for a second fluid are formed alternatingly between the first and second heat transfer plates. Respective third portholes of adjoining heat transfer plates form a porthole channel through the plate package. The first plate interspaces are arranged in fluid communication with the porthole channel. The plate pattern at the second end portion is configured to prevent fluid flow between the first plate interspaces and the porthole channel in a direction in parallel with the longitudinal axis and to guide fluid flow between the first plate interspaces and the porthole channel in a direction perpendicularly to the longitudinal axis.

[0014] Since the first plate interspaces are arranged in fluid communication with the porthole channel formed by the third portholes and since the plate pattern at the second end portion is configured to prevent fluid flow between the first plate interspaces and the porthole channel in a direction in parallel with the longitudinal axis and to guide fluid flow between the first plate interspaces and the porthole channel in a direction perpendicularly to the longitudinal axis - during user of the plate heat exchanger, at the second end portion, distribution of the first fluid in a width direction of the heat transfer plates i.e., perpendicularly to the longitudinal axis, and towards the second porthole, is promoted.

[0015] Thus, in use of the plate heat exchanger, a large portion of the heat transfer surfaces in the first plate interspaces is utilised for heat exchange between the first fluid in the first plate interspaces and the second fluid in the second plate interspaces.

[0016] Particularly, a first fluid that changes phase in the plate heat exchanger benefits from the fluid flow prevention in parallel with the longitudinal axis and the fluid flow guidance in the first plate interspaces as provided by the herein defined configuration of the plate pattern at the second portion of the heat transfer plates.

[0017] Herein, the plate heat exchanger may alternatively be referred to as the heat exchanger.

[0018] Herein, the heat transfer plates also may be referred to as the plates or the plate when referred to in singular. In the technical field, the heat transfer plates may also be referred to as heat exchanger plates or heat exchange plates.

[0019] Each of the heat transfer plates may have a generally rectangular shape with the first end portion arranged at one short side of the rectangular shape and the second end portion arranged at the opposite short side of the rectangular shape. The longitudinal axis may form a longitudinal centre line extending between the first and second end portions in parallel with long sides of the rectangular shape.

[0020] The first and second heat transfer plates may be of different kinds i.e., the plate pattern of ridges and recesses may differ between the first and second heat transfer plates. For instance, the plate pattern may differ in the first and second end portions, such as at the portholes. In use, the plate heat exchanger is arranged for heat exchange between the first and second fluids. The first set of plate interspaces is flowed through by the first fluid and the second set of plate interspaces is flowed through by the second fluid. The first and second fluids flow on opposite sides of each of the heat transfer plates through the plate package. Thus, heat exchange between the first and second fluids is achieved. Herein, the plate interspaces may alternatively be referred to as the interspaces.

[0021] In use of the heat exchanger, the first and second fluids flow in and out of the plate package through porthole channels formed by the first, second, third, and fourth portholes at the first and second end portions of the heat transfer plates. Herein, the porthole channel formed by the first portholes may be referred to as the first porthole channel, the porthole channel formed by the second portholes may be referred to as the second porthole channel, the porthole channel formed by the third portholes may be referred to as the third porthole channel, and the porthole channel formed by the fourth portholes may be referred to as the fourth porthole channel.

[0022] The porthole channels extend through the plate package perpendicularly to the longitudinal axis.

[0023] The first and second plate interspaces are arranged in fluid communication with one porthole channel at each of the first and second end portions.

[0024] In use with a phase changing first fluid, depending on whether the plate heat exchanger operates as a condenser or as an evaporator, the porthole channel formed by the third portholes either forms an outlet for the first fluid or an inlet for the first fluid. A refrigerant utilised in a heat pump circuit is an example of such a phase changing first fluid.

[0025] During use of the plate heat exchanger, heat transfer between the first and second fluids, takes mainly place via the main heat transfer area at the centre portion of the heat transfer plates. However, also the first and second end portions contribute to the heat transfer between the two fluids. Thus, the herein presented plate pattern at the second end portion, which is configured to prevent fluid flow between the first plate interspaces and the porthole channel formed by the third portholes in a direction in parallel with the longitudinal axis and to guide fluid flow between the first plate interspaces and the porthole channel formed by the third portholes in a direction perpendicularly to the longitudinal axis contributes to providing an overall efficient plate heat exchanger. This so, since the prevention of fluid flow between the first plate interspaces and the third porthole channel in a direction in parallel with the longitudinal axis, directs the flow of fluid towards the side of the heat transfer plates where the second portholes are positioned. Thus, it is ensured that the area of the heat transfer plates at the second portholes is utilised for heat exchange between the first and second fluids.

[0026] The herein discussed guiding of fluid flow between the first plate interspaces and the porthole channel in a direction perpendicularly to the longitudinal axis, means that the fluid flow will be directed perpendicularly, or have at least a directional component perpendicular, to the longitudinal axis. Namely, once having flowed past the plate pattern at the second end portion, which plate pattern is configured to prevent fluid flow between the first plate interspaces and the porthole channel in a direction in parallel with the longitudinal axis, the fluid flow may have also a directional component in parallel with the longitudinal axis.

[0027] However, a flow direction purely parallel with the longitudinal axis is prevented by the plate pattern at the second end portion.

[0028] The plate pattern may provide a desired flow resistance for the fluids in the first and second sets of plate interspaces, and / or may promote turbulence in the fluids in the first and second sets of plate interspaces and thus, may provide a certain heat transfer capacity of the relevant plate heat exchanger during use of the plate heat exchanger.

[0029] The first and second plate interspaces may have the same or different depths, seen perpendicularly to the longitudinal axis and in parallel with the porthole channels.

[0030] The number of heat transfer plates and their size and shape provide a certain heat exchange capacity for certain flow rates of the fluids flowing through the heat exchanger.

[0031] In the plate package, the protrusions of the first heat transfer plates abut against the recesses of adjacent second heat transfer plates and similarly, the protrusions of the second heat transfer plates abut against the recesses of adjacent first heat transfer plates. Such abutments between adjacent heat transfer plates may be in singular points e.g., in the main heat transfer area. In some portions of the heat transfer plates the abutment may be in linear form e.g., around the portholes to form the porthole channels. Along edges of the first and second heat transfer plates, the first and second heat transfer plates are arranged in sealing abutment for laterally delimiting the plate interspaces. For instance, the edges may be provided with flanges that stack into each other.

[0032] As mentioned above, in the plate package, the heat transfer plates are permanently joined. Joints between the heat transfer plates may be formed by a joining method in which the plates are subjected to a heat lower than the melting point of the material of the heat transfer plates. Such joining methods may be one of brazing with an added brazing material in the form of a foil, a paste, or a powder comprising e.g., copper or nickel, or joining by means of the material of the heat transfer plates by application of a melting depressant composition applied to the heat transfer plates prior to being heated e.g., as discussed in WO 2013 / 144211.

[0033] Herein, in general discussions, without a defined flow direction through the first plate interspaces, reference is made to a flow to, or from, the third porthole channel i.e. , the porthole channel formed by the third portholes. Accordingly, in general discussions, the porthole channel formed by the third portholes may form an outlet channel for the first fluid in the first plate interspaces or an inlet channel of the first fluid in the first plate interspaces. The same applies to general discussions of the second plate interspaces and the flow of the second fluid at the second porthole channel i.e., the porthole channel formed by the second portholes.

[0034] In the following, occasionally, reference is made to the porthole channel. This reference relates to the porthole channel formed by the third portholes. Other porthole channels are defined by specific reference to the relevant portholes, such as the second, third, or fourth portholes forming the relevant porthole channel.

[0035] According to embodiments, the plate pattern at the second end portion of each first heat transfer plate may comprise a ridge extending from the first heat transfer plate in an adjacent first plate interspace of the set of first plate interspaces, the ridge being joined to an adjacent second heat transfer plate of the set of second heat transfer plates to delimit part of the first plate interspace. At least part of the ridge may extend perpendicularly to the longitudinal axis to prevent fluid flow between the first plate interspaces and the porthole channel formed by the third portholes in a direction in parallel with the longitudinal axis. In this manner, during use of the plate heat exchanger, the flow of the first fluid in the first plate interspaces may be directed to flow to, or from, the porthole channel formed by the third portholes via a midportion of the heat transfer plates between the third and second portholes. According to embodiments, each first and second plate interspace may be partially delimited by a first side edge extending substantially in parallel with the longitudinal axis and by a second side edge extending substantially perpendicularly to the longitudinal axis. A corner portion of each of the first and second heat transfer plates may be formed at the first and second side edges. The third porthole of each of the first and second heat transfer plates may be arranged at the corner portion and a first portion of the ridge may extend from the first side edge towards the longitudinal axis. In this manner, during use of the heat exchanger, a flow of the first fluid along the first side edge at the third porthole may be prevented. The first fluid thus, at the third porthole is forced to flow from, or to, the porthole channel formed by the third portholes via midportions of the heat transfer plates between the first and second portholes i.e., towards a portion of the first plate interspaces where heat exchange with the second fluid in the second plate interspaces is more efficient. Namely, at the second porthole channel, the flowrate of the second fluid is higher than at the first corner portion formed by the first and second side edges.

[0036] According to embodiments, a second portion of the ridge may extend from the first portion of the ridge towards the second side edge. In this manner, during use of the heat exchanger, a flow of the first fluid in the first plate interspaces may be directed towards, or away from, the second portholes close to the second side edge. The first fluid thus, at the third porthole is forced to flow from the third porthole channel, or towards the third porthole channel, close to the second side edge. Accordingly, the first fluid flowing from, or to, the porthole channel formed by the third portholes, is directed to flow from, or towards, the second side edge while passing the entire, or at least a major portion of, the second portholes. This will ensure efficient heat exchange with the second fluid flowing from, or to, the porthole channel formed by the second portholes.

[0037] According to embodiments, the second portion of the ridge may end at a distance from the second side edge such that a passage between the first plate interspace and the porthole channel formed by the third portholes may be formed between the second portion of the ridge and the second side edge. In this manner, during use of the heat exchanger, via the passage, a flow of the first fluid in the first plate interspaces may be directed away from, or towards, the second portholes close to the second side edge. The first fluid thus, via the passage, at the third portholes is forced to flow to, or from, the porthole channel formed by the third portholes towards, or away from, the second portholes close to the second side edge. Accordingly, the first fluid flowing to, or from, the third porthole channel, is directed to flow along the second side edge while passing the entire, or at least a major portion of, the second portholes. This will ensure efficient heat exchange with the second fluid flowing to, or from, the second porthole channel.

[0038] According to embodiments, the passage may have a length within a range of 0.15 - 0.25 of a circumference of the third porthole. In this manner, during use of the plate heat exchanger, the third fluid may be efficiently directed towards the second side edge in the first plate interspaces.

[0039] According to embodiments, the ridge may be arranged adjacent to the porthole channel formed by the third portholes. In this manner, no, or only minimal, surface portions of the heat transfer plates are prevented from being utilised for heat exchange between the first and second fluids.

[0040] According to embodiments, in each second plate interspace a fluid passageway may be formed along the ridge of the first heat transfer plate. In this manner, during use of the plate heat exchanger, the second fluid may be guided via the fluid passageway towards, or from, the first side edge of the heat transfer plates. Accordingly, fluid flow of the second fluid over an entire with of the heat transfer plates is promoted. This ensures efficient heat exchange in the heat exchanger.

[0041] According to embodiments, the first or fourth portholes of adjoining heat transfer plates may form a further porthole channel through the plate package. The plate pattern at the first end portion may be configured to guide fluid flow between the further porthole channel and the first plate interspaces in a direction in parallel with the longitudinal axis and in a direction perpendicularly to the longitudinal axis. In this manner, during use of the heat exchanger, at the further porthole channel, the first fluid may be evenly distributed in the first plate interspaces in its flow from, or to, the further porthole channel.

[0042] Accordingly, the further porthole channel may be either the first porthole channel or the fourth porthole channel. This depends on which of the first and fourth porthole channels is arranged in fluidly communication with the first plate interspaces.

[0043] According to embodiments, each of the heat transfer plates may comprise a metal sheet shaped to form the protrusions and recesses of the plate pattern. Put differently, the heat transfer plates may be made from sheet metal. The heat transfer plates may be manufactured by cutting pieces of sheet metal. In a pressing operation, the pieces are provided with the plate pattern of protrusions and recess and optionally, with angled flanges.

[0044] According to a further aspect of the invention, there is provided a heat pump circuit comprising an expansion device, an evaporator, a compressor, and a condenser, wherein the condenser comprises a plate heat exchanger according to any one of aspects and / or embodiments discussed herein.

[0045] Further features of, and advantages with, the invention will become apparent when studying the appended claims and the following detailed description.

[0046] BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Various aspects and / or embodiments of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

[0048] Figs. 1a and 1b illustrate a plate heat exchanger according to embodiments,

[0049] Figs. 2a and 2b show a first heat transfer plate according to embodiments,

[0050] Figs. 3a and 3b show a second heat transfer plate according to embodiments,

[0051] Figs. 4a - 4d illustrate embodiments of heat transfer plates of a plate package of a plate heat exchanger, and

[0052] Fig. 5 schematically illustrates a heat pump circuit according to embodiments.

[0053] In Figs. 2a - 4c, some areas of the heat transfer plates of no relevance to the present invention have been masked with white areas.

[0054] DETAILED DESCRIPTION

[0055] Aspects and / or embodiments of the invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and / or clarity.

[0056] Figs. 1a and 1b illustrate a side view and a top view of a plate heat exchanger 10 according to embodiments.

[0057] The plate heat exchanger 10 comprises a plurality of heat transfer plates 1 in accordance with any one of the embodiments discussed herein, a first end plate 2, which is provided beside an outermost one of the heat transfer plates 1 , and a second end plate 3, which is provided beside an opposite outermost heat transfer plate 1. The second end plate 3 is not visible in the view of Fig. 1a since it is arranged within a flange 7 of the relevant outermost heat transfer plate 1. Thus, the second end plate 3 is indicated with a broken line in Fig. 1a. A longitudinal axis LA extends along a length wise direction of the plates 1.

[0058] The heat transfer plates 1 are produced through forming of sheet metal and are arranged beside each other. The first end plate 2, the second end plate 3 and the heat transfer plates 1 are permanently joined to each other. At least the heat transfer plates 1 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 overlap and are permanently joined to each other.

[0059] Within the plate package 4, adjoining heat transfer plates 1 of two different kinds delimit therebetween first plate interspaces for a first fluid and second plate interspaces for a second fluid, see below e.g. with reference to Figs. 2a - 4d. The first and second fluids may be any suitable fluids, between which heat is to be transferred during use of the plate heat exchanger 10. However, as discussed herein, the plate heat exchanger 10 is particularly suited for the first fluid being a phase changing fluid, such as a refrigerant.

[0060] The plate heat exchanger 10 has four porthole channels S1 , S2, S3, and S4 formed by portholes in the individual plates 1. A first porthole channel S1 is connected to a connection pipe 11 and communicates with the first or second plate interspaces. A second porthole channel S2 is connected to a connection pipe 12 and communicates with the second plate interspaces. A third porthole channel S3 is connected to a connection pipe 13 and communicates with the first plate interspaces and a fourth porthole channel S4 is connected to a connection pipe 14 and communicates with the first or second plate interspaces. The first and fourth porthole channels S1 , S4 communicate with different of the first and second plate interspaces.

[0061] Connection pipes in fluid communication with the porthole channels S1 , S2, S3, and S4 may be provided extending from the first end plate 2, as disclosed, and / or from the second end plate 3.

[0062] Figs. 2a - 3b illustrate first and second heat transfer plates T, 1” of the plate heat exchanger Figs. 2a and 2b show a first heat transfer plate T according to embodiments. Fig. 2a shows a top view of the first plate T and Fig. 2b shows a perspective view of the first plate T. Figs. 3a and 3b show a second heat transfer plate 1” according to embodiments. Fig. 3a shows a top view of the second plate 1” and Fig. 3b shows a perspective view of the second plate 1”.

[0063] In many aspects, the first and second plates T, 1” are similar in other aspects they differ. The following discussion of Figs. 2a - 3b relates to both the first and second heat transfer plates T, 1”, unless particular reference is made to one of the first or second heat transfer plates T, 1”.

[0064] The plate heat exchanger 10 of Figs. 1a and 1b comprises permanently joined alternatingly arranged first and second plates T, 1”. In the plate package of a plate heat exchanger, the first heat transfer plates T and the second heat transfer plates 1” form at least a main portion of the plate package.

[0065] The heat transfer plates T, 1” have a rectangular shape with two long side edges and two short side edges. In the illustrated embodiments, a first side edge 16 is a long side edge and a second side edge 18 is a short side edge. A longitudinal axis LA extends in parallel with the first side edge 16 and transversely to the second side edge 18.

[0066] Each of the heat transfer plates T, 1” comprise a first end portion 20, a centre portion 22 and a second end portion 24 arranged in succession along the longitudinal axis LA of the respective heat transfer plate T, 1”. The first end portion 20 is provided with a first porthole 26 and a fourth porthole 28, the second end portion 24 is provided with a second porthole 30 and a third porthole 32.

[0067] The centre portion 22 comprises a main heat transfer area 34. The main heat transfer area 34 forms an area, at which during use of the plate heat exchanger, a main part of the heat transfer between the first and second fluids on opposite sides of the first and second plates T, 1” takes place.

[0068] The heat transfer plates T, 1” are provided with a plate pattern of protrusions and recesses. The plate pattern is provided in the main heat transfer area 34 as well as at the first and second end portions 20, 24. The plate pattern may differ between the main heat transfer area 34 and the first and second end portions 20, 24. In the illustrated embodiments, in the main heat transfer area 34 and partially also at the first and second end portions 20, 24 the plate pattern comprises protrusions in the form of diagonally extending ridges alternating with recesses in the form of diagonally extending grooves to form a heat transfer pattern. The heat transfer pattern primarily promotes an efficient heat transfer between the first and second fluids. It may also promote distribution of the first and second fluids over a width of the heat transfer plates T, 1”. However, the present invention is not limited to any particular kind of heat transfer pattern.

[0069] The plate pattern of protrusions and recesses also includes areas around, and close to, the portholes 26 - 32. These are areas primarily devised for forming the porthole channels through the plate package and for fluid flow guiding purposes around the portholes, although some heat transfer may take place also in these areas.

[0070] In the respective first and second end portions 20, 24, each porthole 26 - 32 is surrounded by a porthole area 35’, 35”, as indicated in Figs. 2b and 3b. In a known manner, the porthole areas 35’, 35” are shaped such that, within the heat exchanger and along the respective porthole channel, the first and second heat transfer plates T, 1” abut against each other alternatingly in a sealing manner and alternatingly in a manner defining through flow passages into or out of respective first and second plate interspaces between the first and second plates T, 1”.

[0071] More specifically, in the respective porthole area 35’, 35”, the heat transfer plates T, 1” are provided with circumferential protrusions and recesses configured to abut against corresponding circumferential recesses and protrusions of adjacent heat transfer plates T, 1”. Circumferentially extending joints are arranged around the portholes 26 - 32 where such circumferential protrusions and recesses abut against each other to seal the relevant porthole channel from every second plate interspace between the plates T, 1”. Consequently, the relevant porthole channel will open up into every alternate plate interspace between the plates T, 1”.

[0072] The plate pattern extends between a first plane and a second plane. The first and second planes of one plate T, 1” extend in parallel with the longitudinal axis LA and in parallel with the first and second sides edges 16, 18 of the plate T, 1”. In the plate package, except at its two outermost heat transfers plates T, 1”, each first plane of one plate T, 1” is arranged adjacent to a second plane of an adjacent plate T, 1”. Accordingly, top portions of the protrusions extend in the first plane and bottom portions of the recesses extend in the second plane. Also, the top portions of the circumferential protrusions in the porthole areas 35’, 35” extend in the first plane and bottom portions of the circumferential recesses in the porthole areas 35’, 35” extend in the second plane.

[0073] In the illustrated embodiments, in the first plate T, top portions of the circumferential protrusions in the porthole areas 35’ around the first and second portholes 26, 30 extend in the first plane and bottom portions of the circumferential recesses in the porthole areas 35” around the third and fourth portholes 32, 28 extend in the second plane, see Fig. 2b. Conversely, in the second plate 1”, bottom portions of the circumferential recesses in the porthole areas 35’ around the first and second portholes 26, 30 extend in the second plane and top portions of the circumferential protrusions in the porthole areas 35” around the third and fourth portholes 32, 28 extend in the first plane, see Fig. 3b. Thus, the circumferential joints around the portholes 26 - 32 may be achieved.

[0074] Figs. 4a - 4d illustrate embodiments of three heat transfer plates T, 1” of a plate package of a plate heat exchanger 10 as discussed with reference to Figs. 1a and 1b. Fig. 4a shows a top view of the plates T, 1”, Fig. 4b shows a perspective view of the second end portion 24 of the plates T, 1”, Fig. 4c shows a perspective view cross section along line C - C in Fig. 4a, and Fig. 4d shows a perspective view cross section along line D - D in Fig. 4a.

[0075] Of the three illustrated heat transfer plates T, 1”, and with reference to their positions in the figures, the top and bottom plates T, are first heat transfer plates T as discussed with reference to Figs. 2a and 2b, and the middle plate 1”, is a second heat transfer plate 1” as discussed with reference to Figs. 3a and 3b.

[0076] As discussed above, in the plate package of the plate heat exchanger, there are formed two sets of interspaces between the plates T, 1”. A set of first plate interspaces 36 for a first fluid and a set of second plate interspaces 38 for a second fluid are formed alternatingly between the first and second heat transfer plates T, 1”. In Figs. 4b - 4d one each of the first and second plate interspaces 36, 38 is partially visible.

[0077] It is noted that the uppermost first plate T delimits one of the first plate interspaces 36. Accordingly, Figs. 4a - 4d present a detailed view of inner delimiting surfaces of the first plate interspaces 36. So do also Figs. 2a and 2b. Similarly, Figs. 3a and 3b present a detailed view of inner delimiting surfaces of the second plate interspaces 38 since Figs. 3a and 3b illustrate the second heat transfer plate 1”. As previously discussed, the portholes of the plates T, 1” form porthole channels through the plate package. The second portholes 30 of adjoining heat transfer plates T, 1” form the second porthole channel S2 through the plate package and the third portholes 32 of adjoining heat transfer plates T, 1” form the third porthole channel S3 through the plate package, see also Fig. 1b. The first plate interspaces 36 are arranged in fluid communication with the third porthole channel S3 and the second plate interspaces 38 are arranged in fluid communication with the second porthole channel S2.

[0078] The plate pattern at the second end portion 24 is configured to prevent fluid flow between the first plate interspaces 36 and the third porthole channel S3 in a direction in parallel with the longitudinal axis LA and to guide fluid flow between the first plate interspaces 36 and the third porthole channel S3 in a direction perpendicularly to the longitudinal axis LA.

[0079] In Figs. 4a and 4b, the direction in parallel with the longitudinal axis LA is indicated with a broad arrow DPar and the direction perpendicularly to the longitudinal axis LA is indicated with a broad arrow DPer.

[0080] Generally, this is achieved by the plate pattern of the first and second plates T, 1” being formed such that protrusions and / or recesses of the plate pattern are arranged to abut against each other in the first plate interspaces 36 at the third portholes 32. This abutment extends along a line from the first side edge 16 of the plates T, 1” at least partially in a direction towards an opposite side edge 40 of the plates T, 1”. Thus, during use of the plate heat exchanger, the first fluid in the first plate interspaces 36 will be forced to flow around the abutment. Due to the extension of the abutment, the first fluid will be directed at least partially along the second portholes 30 and flow in a direction perpendicularly to the longitudinal axis LA at the third portholes 32.

[0081] As will be discussed with reference to embodiments, the abutment may have a more elaborate configuration and flow directing function but also such an abutment e.g., as provided by the below discussed ridge 42, will still fall within the above discussed general principle.

[0082] The plate pattern at the second end portion 24 of each first heat transfer plate T comprises a ridge 42 extending from the first heat transfer plate T in an adjacent first plate interspace 36 of the set of first plate interspaces 36. The ridge 42 forms one of the protrusions of the plate pattern. The ridge 42 is joined to an adjacent second heat transfer plate 1” to extend within the first plate interspace 36. At least part of the ridge 42 extends perpendicularly to the longitudinal axis LA to prevent fluid flow between the first plate interspaces 36 and the third porthole channel S3 in the direction DPar in parallel with the longitudinal axis LA.

[0083] In Figs. 4a - 4d, the ridge 42 is clearly visible on the upper first heat transfer plate T. In Figs. 4c and 4d, the ridge 42 of the lower first heat transfer plate T and the abutment between the ridge 42 and the second heat transfer plate 1” is shown. At the abutment, the ridge 42 is joined to the second heat transfer plate 1”.

[0084] Accordingly, fluid communication between the first plate interspaces 36 and the third porthole channel S3 is only provided in an area where the ridge 42 does not extend. Thus, the flow of the first fluid in the first plate interspaces 36 is guided to pass a midportion 44 of the heat transfer plates T, 1” between the third and second portholes 30, 30. Accordingly, during use of the plate heat exchanger, the entire flow of the first fluid has to pass this midportion 44 of the plates T, 1” and accordingly, the first fluid has to pass at least part of the second portholes 30.

[0085] Each first and second plate interspace 36, 38 is partially delimited by a first side edge 16 extending substantially in parallel with the longitudinal axis LA and by a second side edge 18 extending substantially perpendicularly to the longitudinal axis LA. The first and second side edges 16, 18 may be first and second side edges 16, 18 of one of the plates T, 1” delimiting the relevant plate interspace 36, 38. A corner portion 46 of each of the first and second heat transfer plates T, 1” is formed at the first and second side edges 16, 18, see Fig. 4a. The corner portion 46 is a corner portion at the second end portion 24 of the first and second plates T, 1”. The third porthole 32 of each of the first and second heat transfer plates T, 1” is arranged at the corner portion 46.

[0086] A first portion 48 of the ridge 42 extends from the first side edge 16 towards the side edge 40 delimiting the first and second plate interspaces 36, 38, opposite to the first side edge 16.

[0087] A second portion 50 of the ridge 42 extends from the first portion 48 of the ridge 42 towards the second side edge 18.

[0088] Thus, fluid communication between the first plate interspaces 36 and the third porthole channel S3 is directed close to the second side edge 18. Accordingly, during use of the plate heat exchanger, the first fluid will flow past the entire, or at least a major portion of, the second portholes 30.

[0089] According to embodiments, the second portion 50 of the ridge 42 ends at a distance from the second side edge 18 such that a passage 52 between the first plate interspace 36 and the third porthole channel S3 is formed between the second portion 50 of the ridge 42 and the second side edge 18.

[0090] In Fig. 4c, the passage 52 is indicated between the lower first plate T, and the second plate 1”. In Fig. 4d, the position of the passage 52 is indicated at the upper first heat transfer plate T.

[0091] In each first plate interspace 36, the passage 52 provides the only means for fluid communication between the first plate interspace 36 and the third porthole channel S3. During use of the plate heat exchanger, the passage 52 directs flow of the first fluid in the first plate interspaces 36 to pass the entire, or at least a major portion of, the second porthole 30.

[0092] According to embodiments, the passage 52 may have a length within a range of 0.15 - 0.25 of a circumference of the third porthole 32. Thus, during use of the plate heat exchanger, the third fluid may be efficiently directed towards the second side edge 18 in the first plate interspaces 36.

[0093] The length of the passage 52 may be in a direction substantially in parallel with the longitudinal axis LA.

[0094] The ridge 52 may be arranged adjacent to the third porthole channel S3.

[0095] Thus, no, or only minimal, surface portions of the plates T, 1” are prevented from being utilised for heat exchange between the first and second fluids. For instance, the ridge 52 may be formed at a distance from the third porthole 32 in the first plates T such that enough material of the plate T remains for circumferentially joining the first and second plates T, 1” around the third portholes 32 to block entrance from the third porthole channel S3 into the second plate interspaces 38.

[0096] In each second plate interspace 38 a fluid passageway 54 may be formed along the ridge 52 of the first heat transfer plate T, see Fig. 4d. Thus, during use of the plate heat exchanger, the second fluid may be guided via the fluid passageway 54 towards, or from, the first side edge 16 of the heat transfer plates T, 1”. Accordingly, fluid flow of the second fluid over an entire width of the heat transfer plates T, 1” is promoted.

[0097] The first and fourth portholes 26, 28 of adjoining heat transfer plates T, 1” form first and fourth porthole channels S1, S4 through the plate package, see Fig. 4a. The plate pattern at the first end portion 20 may be configured to guide fluid flow between the first or fourth porthole channel S1, S4 and the first plate interspaces 36 in a direction in parallel with the longitudinal axis LA and in a direction perpendicularly to the longitudinal axis LA.

[0098] In the illustrated embodiments, the fourth porthole channel S4 is arranged in fluid communication with the first plate interspaces 36. Accordingly, in the illustrated embodiments, the plate pattern of the first and / or second heat transfer plates T, 1” at the first end portion 20 is configured to guide fluid flow between the fourth porthole channel S4 and the first plate interspaces 36 in a direction in parallel with the longitudinal axis LA and in a direction perpendicularly to the longitudinal axis LA.

[0099] Thus, during use of the heat exchanger, at the fourth porthole channel S4, the first fluid may be evenly distributed in the first plate interspaces 36 at the fourth porthole channel S4.

[0100] In alternative embodiments, the plates T, 1” may be configured for the first porthole channel S1 to be arranged in fluid communication with the first plate interspaces 36.

[0101] Generally, the plate heat exchanger 10 may be utilised for heat transfer between a first fluid in the form of a phase changing fluid, such as refrigerant utilised in a heat pump circuit, in the first plate interspaces 36 and a second fluid in the second plate interspaces 38.

[0102] Particularly, the plate heat exchanger 10 thus, may form a condenser in a heat pump circuit, see also below with reference to Fig. 5.

[0103] Accordingly, during use, the first fluid, in the gaseous phase flows into the first plate interspaces 36 through a porthole channel at the first end portion 20 of the plates T, 1”. In the illustrated embodiments, the first fluid flows into the first plate interspaces via the fourth porthole channel 28. When the first fluid has condensed i.e. , changes phase from gaseous phase to liquid phase, in the first plate interspaces 36, it flows from the first plate interspaces 36 into the third porthole channel S3. The present flow directing arrangement in the plates T, 1” and the plate pattern of protrusions and recesses at the third portholes 32 thus, ensures a full utilisation of the plates T, 1” for heat transfer with the second fluid also at the second portholes 30.

[0104] As the first fluid condenses in the first plate interspaces 36, the volume of the first fluid is reduced and accordingly, the flow resistance provided by the comparatively small cross sectional area between the first plate interspaces 36 and the third portholes 32, such as e.g., provided by the passage 52, does not impede the flow of the first fluid through the first plate interspaces 36.

[0105] Fig. 5 schematically illustrates a heat pump circuit 56 according to embodiments.

[0106] The heat pump circuit 56 comprising an expansion device 58, an evaporator 60, a compressor 62, and a condenser 64, wherein the condenser 64 is a plate heat exchanger 10 according to any one of aspects and / or embodiments discussed herein.

[0107] It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the invention, as defined by the appended claims.

Claims

CLAIMS1. A plate heat exchanger (10) comprising a plate package (4) of permanently joined heat transfer plates (1’, 1”), wherein each of alternatingly arranged first heat transfer plates (T) and adjoining second heat transfer plates (1”) of the plate package (4) comprises a first end portion (20), a centre portion (22) and a second end portion (24) arranged in succession along a longitudinal axis (LA) of the respective heat transfer plate (T, 1”), the first end portion (20) being provided with a first porthole (26) and a fourth porthole (28) , the second end portion (24) being provided with a second porthole (30) and a third porthole (32), and the centre portion (22) comprising a main heat transfer area (34), wherein the heat transfer plates (1’, 1”) are provided with a plate pattern of protrusions and recesses, wherein a set of first plate interspaces (36) for a first fluid and a set of second plate interspaces (38) for a second fluid are formed alternatingly between the first and second heat transfer plates (T, 1”), wherein respective third portholes (32) of adjoining heat transfer plates (1’, 1”) form a porthole channel (S3) through the plate package (4), wherein the first plate interspaces (36) are arranged in fluid communication with the porthole channel (S3), wherein the plate pattern at the second end portion (24) is configured to prevent fluid flow between the first plate interspaces (36) and the porthole channel (S3) in a direction in parallel with the longitudinal axis (LA) and to guide fluid flow between the first plate interspaces (36) and the porthole channel (S3) in a direction perpendicularly to the longitudinal axis (LA).

2. The plate heat exchanger (10) according to claim 1, wherein the plate pattern at the second end portion (24) of each first heat transfer plate (T) comprises a ridge (42) extending from the first heat transfer plate (T) in an adjacent first plate interspace (36) of the set of first plate interspaces (36), the ridge (42) being joined to an adjacent second heat transfer plate (1”) to delimit part of the first plate interspace (36), wherein at least part of the ridge (42) extends perpendicularly to the longitudinal axis (LA) to prevent fluid flow between the first plate interspaces (36) and the porthole channel (S3) formed by the third portholes (32) in a direction in parallel with the longitudinal axis (LA).

3. The plate heat exchanger (10) according to claim 2, wherein each first and second plate interspace (36, 38) is partially delimited by a first side edge (16) extending substantially in parallel with the longitudinal axis (LA) and by a second side edge (18) extending substantiallyperpendicularly to the longitudinal axis (LA), wherein a corner portion (46) of each of the first and second heat transfer plates (1’, 1”) is formed at the first and second side edges (16, 18), wherein the third porthole (32) of each of the first and second heat transfer plates (T, 1”) is arranged at the corner portion (46), and wherein a first portion (48) of the ridge (42) extends from the first side edge (16) towards a side edge (40) delimiting the first and second plate interspaces (36, 38) opposite to the first side edge (16).

4. The plate heat exchanger (10) according to claim 3, wherein a second portion (50) of the ridge (42) extends from the first portion (48) of the ridge (42) towards the second side edge (18).

5. The plate heat exchanger (10) according to claim 4, wherein the second portion (50) of the ridge (42) ends at a distance from the second side edge (18) such that a passage (52) between the first plate interspace (36) and the porthole channel (S3) formed by the third portholes (32) is formed between the second portion (50) of the ridge (42) and the second side edge (18).

6. The plate heat exchanger (10) according to claim 5, wherein the passage (52) has a length within a range of 0.15 - 0.25 of a circumference of the third porthole (32).

7. The plate heat exchanger (10) according to any one of claims 2 - 6, wherein the ridge (42) is arranged adjacent to the porthole channel (S3) formed by the third portholes (32).

8. The plate heat exchanger (10) according to any one of claims 2 - 7, wherein in each second plate interspace (38) a fluid passageway (54) is formed along the ridge (42) of the first heat transfer plate (T).

9. The plate heat exchanger (10) according to any one of the preceding claims, wherein respective first or fourth portholes (26, 28) of adjoining heat transfer plates (T, 1”) form a further porthole channel (S1, S4) through the plate package (4), and wherein the plate pattern at the first end portion (20) is configured to guide fluid flow between the further porthole channel (S1, S4) and the first plate interspaces (36) in a direction in parallel with the longitudinal axis (LA) and in a direction perpendicularly to the longitudinal axis (LA).

10. The plate heat exchanger (10) according to any one of the preceding claims, wherein each of the heat transfer plates (T, 1”) comprises a metal sheet shaped to form the protrusions and recesses of the plate pattern.

11. A heat pump circuit (56) comprising an expansion device (58), an evaporator (60), a compressor (62), and a condenser (64), wherein the condenser (64) comprises a plate heat exchanger (10) according to any one of the preceding claims.

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