Heat exchanger

Abstract

The present disclosure relates to a plate heat exchanger (1) for heat exchange between at least two fluids which comprises a stack (2) of alternatingly arranged plate elements of a first type (3) and plate elements of a second type (4). The plate elements of the first type (3) and the plate elements of the second type (4) define alternatingly arranged first flow paths (5) and second flow paths (6) between each other, wherein each first flow path (5) extends from a first inlet (7) to a first outlet (8) and each second flow path (6) extends from a second inlet (9) to a second outlet (10). A connection element (11) interconnects the plate elements of the first type (3) and the plate elements of the second type (4) to each other by a holding structures (12) defining recess (13), which encompasses superimposed outer edges (14) of neighboring plate elements (3, 4) in the region of the first and second inlets (7, 9) and / or in the region of the first and second outlets (8, 10) and thereby seals the plate elements (3, 4) in the region of the first and second inlets (7, 9) and / or in the region of the first and second outlets (8, 10).

Description

FIELD OF THE DISCLOSURE

[0001] The present disclosure relates to a plate heat exchanger comprising a holding structure, which defines a recess for encompassing aligned outer edges of neighboring plate elements of the plate heat exchanger in the region of the first and second inlets and / or in the region of the first and second outlets, as well as a method for providing such a plate heat exchanger.BACKGROUND OF THE DISCLOSURE

[0002] WO2020095188A1 published on 14.05.2020 on behalf of the applicant relates to a method for providing a heat exchanger block with a housing. The heat exchanger block comprises at least a first outer surface region and a second outer surface region opposite said first outer surface region. The housing further comprises at least a first housing portion which covers / engages the first outer surface region of the heat exchanger block and a second housing portion, which is located opposite the first housing portion and covers / engages the second outer surface region of the heat exchanger block. The method comprises at least the steps of molding the first housing portion to the first outer surface region and molding the second housing portion to the second outer surface region.SUMMARY OF THE DISCLOSURE

[0003] Plate heat exchangers are known and form a subcategory amongst heat exchangers. Plate heat exchangers (PHE) are a specialized design well suited to transfer heat between medium- and low-pressurized fluids. Conventional plate heat exchangers are typically formed by multiple metal plates, which define flow paths between each other to transfer heat between at least two fluids. This has a major advantage over other types of heat exchangers, like tubular heat exchangers, in that the fluids are exposed to a much larger surface area because the fluids are spread out over the plates. This facilitates the transfer of heat, and greatly increases the speed of the temperature change between the at least two fluids.

[0004] A special subcategory of plate heat exchangers are so called enthalpy exchangers, which can recover both thermal and latent energy, e.g. from the stale air extracted from wet rooms around a home. The additional energy, which would otherwise be lost, is typically transferred to a counter-flowing fluid, e.g. an incoming fresh air stream before being supplied to habitable rooms. Enthalpy exchangers are typically used in so called Energy Recovery Ventilation (ERV) systems, as opposed to sole Heat Recovery Ventilation (HRV) systems. Enthalpy exchangers typically comprise heat exchange elements, which are made of or are fitted with a membrane material, which enables the crossover of moisture, as well as heat. As the humidity is transferred as water vapor, by diffusion, enthalpy heat exchangers are perfectly suited to counteract both hot and humid indoor climates during the summer months, and drier and cold indoor environments during the winter months.

[0005] Both conventional heat exchangers and enthalpy exchangers are typically assembled from a number of plate elements of a first type and plate elements of a second type. Such plate elements may be considered as heat exchange elements. The plate elements of known heat exchangers, as well as enthalpy exchangers, are typically welded, semi-welded and / or brazed to each other at the outer edges of aligned plate elements, thereby forming alternating flow paths. The flow paths are separated at their largest surface by the plate elements. To even further increase the surface area and guide the flow of the fluid, the plate elements are typically corrugated. The plates used in a plate heat exchanger are typically obtained by one piece pressing of metal plates for heat exchangers or plates made of a polymer material for enthalpy exchangers. In the context of enthalpy exchangers, ultrasonic welding and / or laser welding are typically used for connecting the aligned plate elements to each other. The welding processes are strongly dependent on the respective materials in terms of their applicability and cannot be used universally.

[0006] Particularly in the case of heat exchange elements made of formable membranes, material combinations are used which cannot be processed with conventional welding processes without major adaptation effort, making the processes complicated and inflexible. Welding heat exchange elements made of formable membranes is time consuming, because each pair of two aligned plate elements has to be joined individually. As an alternative to welding, partial foaming / molding is possible. The downside of that method is that a lot of surface area is lost. In addition, foaming needs additional volume, leading to a greater size of the overall heat exchanger, which is not desired.

[0007] One objective of the present disclosure can therefore be seen in improving the known heat exchangers, in particular providing a material independent joining process for the plate elements of the heat exchanger and / or a plate heat exchanger which can be produced in a more efficient manner.

[0008] The present disclosure relates to a plate heat exchanger for heat exchange between at least two fluids. The plate heat exchanger is formed by a stack of alternatingly arranged plate elements of a first type and plate elements of a second type. The plate elements of the first type and the plate elements of the second type may both be made from an essentially planar base element with fluid guiding ribs, as will be described in more detail below noted. The plate elements can be delimited by a circumferential outer edge and differ from each other in the shape of the ribs and corrugations. The plate elements of the first type and the plate elements of the second type define alternatingly arranged first flow paths and second flow paths between each other, wherein each first flow path extends from a first inlet to a first outlet and each second flow path extends from a second inlet to a second outlet. The plate elements of the first type may be considered as first plate elements and the plate elements of the second type as second plate elements. The plate elements of the first type and the plate element of the second type may for example differ from each other, in particular only differ from each other, in the configuration and / or arrangement of beadings, ribs and / or corrugations. The flow paths are formed by alternatingly superimposing plate elements of the first type and of the second type.

[0009] The plate elements of the first type and the plate elements of the second type may extend along a longitudinal axis and are typically alternatingly arranged with respect to each other parallel to the longitudinal axis. The alternatingly arranged first flow paths and second flow paths may be created by beadings and / or recesses, which are stamped into the plate elements of the first type and the plate elements of the second type. In the assembled state, the beadings and / or recesses of the first flow paths and the second flow paths may be laterally displaced with respect to each other or shaped to opposite sides of the plates elements of the first and second type, to form the first flow paths and the second flow paths between each other.

[0010] The plate elements of the first and second type can be formed from a flat panel with the fluid-guiding ribs and the longitudinal ribs being formed by shaping the plate elements accordingly. The plate elements are usually delimited by a circumferential outer edge. To form and delimit the fluid paths, the stack is formed by superimposing plate elements of the first and second type. The plate elements can be superimposed by arranging the outer edges of the plate elements of the first and second type onto one another. To avoid the need for a welding step, a connection element can be used to interconnect the plate elements of the first type and the plate elements of the second type to each other by holding structures of the connection element which define, in particular each define, a recess. The connection element can be arranged in the region of the first and second inlets and / or in the region of the first and second outlets of the plate elements of the first type and of the second type by sliding the connection element onto the outer edges. In particular embodiments, the connection element is slid onto the outer edges in a direction parallel to the outer edges. The direction in parallel to the outer edges refers to the direction along which the outer edges extend. Thus, the connection element may in such embodiments not be pushed perpendicularly onto the outer edges of neighboring plate elements of the first type and the second type (e.g. not perpendicular to the direction along which they extend). The recess thereby preferably encompasses the superimposed outer edges of neighboring plate elements of the first type and of the second type. Sliding the connection element in this manner onto the outer edge can help to align and seal the plate elements of the first type and of the second type without buckling the plate elements, during application of the connection element.

[0011] The outer edges of superimposed plate elements of the first and second type may in some embodiments be in direct contact with each other. In some embodiments, the outer edges of superimposed plates of the first and second type contact each other in a planar manner. The recess can encompass superimposed outer edges of neighboring plate elements of the first type and of the second type in the region of the first and second inlets and / or in the region of the first and second outlets and thereby provides a sealing connection between the plate elements of the first type and of the second type in the region of the first and second inlets and / or in the region of the first and second outlets. The recess can be in form of a longitudinal groove which in the mounted state of the connection element encompasses the outer edges of the plate elements.

[0012] By using a connection element, a joining process, like state of the art welding of the individual layers can be eliminated. The manufacturing process of the heat exchanger can thus be considerably simplified. The uncertainties arising from the previous welding process are also eliminated, e.g. defective welds, dimensional deviations due to burn-off or melt flow in the region of the welds and the therefrom resulting rework. In addition, the stability of the overall heat exchanger is improved by the connection elements at the first and second inlets and / or first and second outlets. The connection elements can in addition act as a contact protection at the otherwise sensitive first and second inlets and first and second outlets. The dimensional accuracy of the stack of the individual plate elements can be improved by the use of a connection element in form of a grid. Due to the resulting constrained position of the plate elements with respect to each other, they are aligned, which is also a requirement for achieving a positive transmission characteristics of the heat exchanger.

[0013] The plate elements of the first and / or the second type can be in the simplest form rectangular or rhomb shaped or a combination thereof, forming a crossflow heat exchanger. In a variation the plate elements may comprise a rectangular intermediate zone and thereto adjacent first and second inlet / outlet sections (first and second cross-flow zones) forming a counter / parallel-flow heat exchanger with a hexagonal footprint. The plate elements of the first and / or the second type may be circumferentially delimited by an outer edge, which can be at least partially designed as a folding or a bulge.

[0014] The plate elements of the first and second type may each extend along a longitudinal axis and include a first cross-flow zone, a second cross-flow zone and an intermediate zone located along the longitudinal axis between the first and second cross-flow zones. When looking in the direction of the longitudinal axis, the first of the two fluids is fed into the heat exchanger through the first inlet into the first cross-flow zone and flows along the longitudinal direction through the first cross-flow zone into the intermediate zone and subsequently the second cross-flow zone, before exiting the heat exchanger through the first outlet. The second of the two fluids is fed into the heat exchanger through the second inlet, being with regard to the longitudinal direction either located adjacent (parallel flow heat exchanger) or opposite to the first inlet (counter-flow heat exchanger). The second fluid also flows along the longitudinal direction through the first cross-flow zone, the intermediate zone and the second cross-flow zone, before it exits the heat exchanger through the second outlet.

[0015] The first flow paths and the second flow paths can be designed, such that the two fluids flow in the region of the intermediate zone in opposite directions but essentially parallel with respect to the longitudinal axis and with respect to each other. In case of a counter-flow heat exchanger, the first cross-flow zone of the first flow path can be arranged adjacent to the second cross-flow zone of the second flow path and vice versa. This results in a fluid guidance within the heat exchanger such that after the entry of the one fluid into the heat exchanger, it first flows through the first cross-flow zone, i.e. heat is exchanged with the other fluid such that both fluid flows intersect.

[0016] The counter-flow zone is subsequently passed, in which the two fluids flow diametrically, e.g. opposite, to one another. This is followed by the intermediate zone where the two fluids flow parallel to each other, before entering the second cross-flow zone, in which the two fluid flows intersect again. From their first and second inlets to their respective first and second outlets the two flows resemble a cross with respect to each other. However, the fluid flows are always separated from one another by the plate elements of the first type and of the second type, which are arranged in the stack in an alternating manner. To delimit the flow paths, except for the first and second inlets and first and second outlets, the outer edges of the plate elements of the first type and the plate elements of the second type may be aligned with each other in that they are in physical contact with other.

[0017] Good results regarding heat exchange are achieved when the intermediate zone, either as counter-flow zone or identical-flow zone, is longer than each of the cross-flow zones. In particular, the counter-flow zone or the identical-flow zone can be three times, preferably four times, particularly more than four times longer than the length of a cross-flow zone (each as seen looking in the direction of the longitudinal axis). Instead of the counter-low zone, there can also be the aforementioned identical-flow zone, i.e. in this zone, the two fluid flows flow in identical directions. This requires that both fluid flows are fed to the same front side of the heat exchanger and removed from the same front side of the heat exchanger.

[0018] To be able to guide the first and second fluid accordingly, at least one fluid-guiding rib can be arranged between the plate elements of the first and second type in the first cross-flow zone and / or the second cross-flow zone and preferably at least one longitudinal rib is arranged in the intermediate zone extending along the longitudinal axis. The fluid-guiding rib may be arranged inclined with respect to the longitudinal axis. The fluid-guiding rib of the plate element of the first type and the fluid-guiding rib of the plate element of the second type can be arranged opposing, forming a cross with each other. The first and second inlets and / or outlets are arranged inclined with respect to the longitudinal axis and the at least one fluid-guiding rib in the first cross-flow zone and / or the second cross-flow zone is arranged inclined with respect to the longitudinal axis, preferably perpendicular to the first and second inlets and / or outlets.

[0019] The connection element can be formed as a grid, comprising a plurality of holding structures and transversal ribs bridging neighboring holding structures. The grid may comprise a plurality of holding structures, which are arranged in parallel to each other. Each holding structure may define one recess for encompassing the outer edge of one plate element of the first type and the thereto-aligned outer edge of one plate element of the second type. The transversal ribs bridging neighboring holding structures may be arranged perpendicular to the holding structures, thereby forming a grid with rectangular orifices. A connection element in form of a grid can be especially beneficial for a fast assembly process as well as providing additional stability for the stack of plate elements. The transversal ribs are mainly for providing stability for the holding structures, which can be designed as elongated bars comprising and / or defining the recesses.

[0020] In a top view on the connection element, the transversal ribs of the connection element and the fluid-guiding ribs in the first cross-flow zone and / or the second cross-flow zone can be arranged aligned to each other. This leads to favorable flow characteristics in that there are no major turbulences in the first and second inlets or outlet.

[0021] The connection element may comprise a guiding chamfer adjacent to an end of the recess, defining a gap being larger than a thickness of the neighboring plate elements in the region of the first and second inlets and / or outlets, such that the connection element is slidable over the outer edges of the plate elements. The guiding chamfers are provided for the assembly of the connection elements. When sliding the connection element onto the preassembled stack of plate elements, the guiding chafers center the two plate elements with respect to each other. The guiding chamfer can be funnel shaped, with the recess having a uniform cross-section over the entire length of the recess, except for the guiding chamfer comprising a widening cross section towards the end of the recess.

[0022] To secure the assembled connection element in place and at the same time assure that the stack of plate elements is airtight and sealed, the connection element can be connected to the plate elements of the first and second type by an adhesive, preferably circumferentially and adjacent to the guiding chamfers. In case of a connection element in form of the grid, an adhesive bead can be applied which encircles the grid on its outer edge. The stack of alternatingly arranged plate elements of the first type and plate elements of the second type with mounted connection element can form a self-contained and sealed subassembly.

[0023] Therefore, the adhesive can in addition also be applied to the remaining segments of the outer edges, apart from the first and second inlets and outlets. This ensures that the stack of alternatingly arranged plate elements is sealed and forms a fluid tight assembly in itself. After arranging the connection elements and sealing the connection elements as well as the remaining segments of the outer edges, the only remaining openings to the flow paths are the first and second inlet and outlet openings. To protect the sealed subassembly from mechanical damage, the plate heat exchanger may be accommodated in an additional casing, in particular a separate casing. The casing typically fulfills the function of protecting the plate heat exchanger, in particular the stack of alternatingly arranged plate elements of the first and second type from mechanical damage. However, as described below. The casing may typically not provide an adequate sealing of the stack of alternatingly arranged plate elements of the first type and plate elements of the second type. The casing typically merely provides protection, e.g. against physical impacts.

[0024] The plate heat exchanger may be an enthalpy heat exchanger. The plate elements of the first and second type each can comprise heat exchange plates, which are perforated or with an inherent pore structure, which is preferably on at least one side coated by a thin polymer layer with water vapor transmission characteristics. The coating of the heat exchange plates may comprise a polymer, preferably a thermoplastic polymer. The heat exchange plates can be produced by thermal processing in form of a thermal forming step. The thermoplastic polymer can be polystyrene (PS), polyvinyl chloride (PVC), viscose or polyester, such as polyethylene terephthalate (PET), or co-polyester are selected as thermoplastic polymer for the coating. The polymer may not include any plasticizer. The polymer may in addition comprise a biocide (bactericide and / or fungicide).

[0025] In an embodiment, the heat exchange plate is a fabric, preferably a nonwoven fabric. The fabric may include thermoplastic fibers only or a combination of thermoplastic fibers and thermoset fibers or a combination of thermoplastic fibers and a resin or a combination of thermoplastic fibers and inorganic fibers. The fabric may include multicomponent or bi-component fibers together with standard thermoset and / or thermoplastic fibers. The fabric can include more than 50 wt.% multicomponent or bi-component fibers and may include multicomponent or bi-component fibers only. In addition, the fabric may include metal fibers and / or wick fibers providing high thermal conductivity together with mechanical strength and high capillary action ("humidity conductivity"), respectively. The inorganic fibers may be glass fibers, silicon carbide fibers or any mineral fiber.

[0026] In case of an enthalpy heat exchanger, the connection element may have additional advantages. Not only may the inflow and pressure drop behavior be influenced positively, but the connection element, especially in form of a grid, may also reduce the flammability of the heat exchanger elements. This can be achieved by selecting a suitable flame resistant material for the connection element. The connection element can also be made of an intumescent material, which "swells" or foams in case of fire. Such a material increases in volume and decreases in density when exposed to heat. After swelling, the material may close the first and second inlet and / or first and second outlet openings and thereby act as a flame and heat barrier.

[0027] A method for providing a plate heat exchanger typically comprising at least the following method steps: Providing a number of plate elements of the first type and plate elements of a second type; Forming a stack of alternatingly arranged plate elements of the first type and plate elements of the second type such that the plate elements define alternatingly arranged first flow paths and second flow paths with each first flow path extending from a first inlet to a first outlet and each second flow path extending from a second inlet to a second outlet; Arranging a connection element in the region of the first and second inlets and / or in the region of the first and second outlets of the plate elements of the first type and of the second type by sliding the connection element onto the outer edges such that the recess encompasses the superimposed outer edges of neighboring of the plate elements of the first type and of the second type.

[0028] In some embodiments, the connection element is typically slid such on the outer edges that it is slid at the same time over at least some, or even all of the outer edges of the plate elements of the stack.

[0029] After arranging the connection element in the region of the first and second inlets and / or in the region of the first and second outlets, the connection element can be secured in position by applying a circumferential bead of adhesive enclosing and sealing the connection element. The bead of adhesive can delimit the recess of the connection element, in case of a connection element in form of a grid the number of recesses. The adhesive may ensure that the connection element will not slip in an unwanted manner along the outer edges and that any remaining air gap can be sealed in an airtight manner.

[0030] In addition to applying a circumferential bead of adhesive enclosing and sealing the connection element, after arranging the connection element in the region of the first and second inlets and / or in the region of the first and second outlets of the plate elements of the first type and of the second type, the uncovered segments of the outer edges may be sealed by applying an adhesive, in particular a bead of adhesive.

[0031] To simplify and accelerate the assembly process, the uncovered segments of the outer edges may be sealed by applying the adhesive in form of a pasty adhesive and / or a foam adhesive, preferably in form of a continuous layer of foam adhesive. For forming the stack, especially before the connection element and adhesive is applied, the plate elements of the first and second type can be alternatingly placed in a stacking device, until the connection element is mounted and the plate heat exchanger forms a self-contained and sealed assembly. After pre-assembling the self-contained and sealed assembly the plate heat exchanger can enclosed by assembling the additional casing, preferably comprising side plates, a top plate and a bottom plate.

[0032] It is to be understood that both the features described in the context of the plate heat exchanger and the features described in the context of the method for providing a plate heat exchanger can be used interchangeable.

[0033] It is to be understood that both the foregoing general description and the following detailed description present embodiments are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings which should not be considered as limiting to the disclosure described in the appended claims. The drawings show: Fig. 1a perspective view on a first variation of the plate heat exchanger with the casing in an exploded view; Fig. 2a perspective view on a first variation of the connection element in form of a grid in Fig. 2a and a detailed view thereof in Fig. 2b; Fig. 3a perspective view on a first variation of a matching pair of a plate elements of the first type and a plate elements of the second type; Fig. 4a perspective view on a first variation of a stack of alternatingly arranged plate elements according to Figure 3; Fig. 5a perspective view on a first variation of the stack according to Figure 4 with the connection element in form of a grid being slid onto the stack; Fig. 6a perspective view on the stack according to Figure 5 with a continuous layer of adhesive being applied to the stack; Fig. 7a perspective view on the plate heat exchanger being assembled and forming a self-contained and sealed subassembly; Fig. 8a perspective view on the plate heat exchanger being assembled with thereto mounted casing. DESCRIPTION OF THE EMBODIMENTS

[0035] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible like reference numbers will be used to refer to like components or parts.

[0036] Figure 1 shows a perspective view on a first variation of the plate heat exchanger 1 with the casing 27 in an exploded view. The shown variation of the plate heat exchanger 1 for heat exchange between at least two fluids comprises a stack 2 of pre-assembled plate elements of a first 3 and second type 4, which are arranged alternatingly. The shown plate heat exchanger 1 is an enthalpy heat exchanger with alternatingly arranged plate elements of the first type 3 and plate elements of the second type 4 being, for example made of a fibrous material.

[0037] The shown connection element 11 is in form of a grid 15, which interconnects the plate elements of the first type 3 and the plate elements of the second type 4 to each other by the holding structures 12, which each define a recess. The recesses each encompass superimposed outer edges of neighboring plate elements 3, 4 in the region of the first and second inlets 7, 9 and / or in the region of the first and second outlets 8, 10 and thereby seals the plate elements 3, 4 in the region of the first and second inlets 7, 9 and / or in the region of first and second outlets 8, 10. As stated above, the shown plate heat exchanger 1 is an enthalpy exchanger with the plate elements of the first 3 and second type 4 each comprising a heat exchange plate 19, which is perforated or with an inherent pore structure. To provide the necessary stability, the heat exchange plates 19 are on at least one side coated by a thin polymer layer 20 with water vapor transmission characteristics.

[0038] Figure 2 shows a perspective view on a first variation of the connection element 11 in form of a grid 15 in Figure 2a and a detailed view thereof in Figure 2b. The grid 15 comprises a plurality of holding structures 12 and transversal ribs 16 bridging neighboring holding structures 12. The shown holding structures 12 each comprise a recess 13 and a guiding chamfer 17, defining a gap between them. The gap is larger than a thickness of the neighboring plate elements in the region of the first and second inlets and / or in the region of the first and second outlets such that the connection element 11 is slideable over the outer edges. The connection element 11 can be connected to the plate elements of the first and second type by an adhesive, preferably circumferentially and adjacent to the guiding chamfers 17.

[0039] Figures 3 to 8 show the assembly process of the plate heat exchanger 1 step by step. The most essential steps are shown by Figures 3 to 5. First, a number of plate elements of the first type 3 and plate elements of a second type 4 are provided, thereby defining alternatingly arranged first flow paths 5 and second flow paths 6. Each first flow path 5 thereby extends from a first inlet 7 to a first outlet 8 and each second flow path 6 extends from a second inlet 9 to a second outlet 10, as shown by Figure 4. A stack 2 is formed by alternatingly arranging plate elements of the first type 3 and plate elements of the second type 4 such that the plate elements 3, 4 come at least partially in contact with each other along their outer edges 14, as shown by Figure 3. To seal the stack in the region of the first 7 and second inlets 9 and / or in the region of the first 8 and second outlets 10, the connection element 11 is arranged in the region of the first and second inlets 7, 9 and / or in the region of the first and second outlets 8, 10 of the plate elements of the first type 3 and of the second type 4 by sliding the connection element 11 onto the outer edges 14 such that the recess 13 encompasses the superimposed outer edges 14 of neighboring of the plate elements of the first type 3 and of the second type 4 as shown by Figures 5.

[0040] Figure 3 shows a perspective view on a first variation of a matching pair of plate elements of the first type 3 and a plate elements of the second type 4. The shown plate elements of the first 3 and / or the second type 4 comprise a rectangular intermediate zone 23 and thereto adjacent inlet / outlet sections (first and second cross-flow zones) which are triangular. The plate elements of the first 3 and the second type 4 are circumferentially delimited by an outer edge 14, which is designed as a folding or a bulge. The plate elements of the first 3 and second 4 type extend along a longitudinal axis x and include a first cross-flow zone 21, a second cross-flow zone 22 and an intermediate zone 23 located along the longitudinal axis x between the first 21 and second 22 cross-flow zones.

[0041] When looking in the direction of the longitudinal axis x, the first of the two fluids is fed into the heat exchanger 1 through the first inlet 7 into the first cross-flow zone 21 and flows along the longitudinal direction through the first cross-flow zone 21 into the intermediate zone 23 and subsequently the second cross-flow zone 22, before exiting the heat exchanger 1 through the first outlet 8. The second of the two fluids is fed into the heat exchanger 1 through the second inlet 9, being in the shown variation with regard to the longitudinal direction located opposite to the first inlet 7. The second fluid also flows along the longitudinal direction through the first cross-flow zone 21, the intermediate zone 23 and the second cross-flow zone 22, before it exits the heat exchanger 1 through the second outlet 10.

[0042] Figure 4 shows a perspective view on a first variation of a stack 2 of alternatingly arranged plate elements 3, 4. The plate elements of the first 3 and second type 4 are arranged in a stacking device 32 until the connection element 11 is mounted and the plate heat exchanger 1 forms a self-contained and sealed assembly 26. The plate elements of the first type 3 and the plate elements of the second type 4 define alternatingly arranged first flow paths 5 and second flow paths 6 between each other, wherein each first flow path 5 extends from a first inlet 7 to a first outlet 8 and each second flow path 6 extends from a second inlet 9 to a second outlet 10. The shown first and second inlets 7, 9 and first and second outlets 8, 10 are arranged inclined with respect to the longitudinal axis x. The shown fluid-guiding ribs 24 in the first cross-flow zone 21 and in the second cross-flow zone 22 are arranged inclined with respect to the longitudinal axis x, preferably perpendicular to the first and second inlets 7, 9 and / or first and second outlets 8, 10, while the longitudinal ribs 25 in the intermediate zone 23 are arranged parallel with respect to the longitudinal axis x.

[0043] Figure 5 shows a perspective view on a first variation of the stack 2 according to Figure 4 with the connection element 11 in form of a grid 15, which is slid onto the stack 2. It can be seen that the connection element 11 is slid onto the outer edges 14 in a direction parallel to the outer edges, i.e. in parallel to the direction the outer edges 14 extend. In a top view on the connection element 11, the transversal ribs 16 of the connection element 11 and the fluid-guiding rib 24 in the first cross-flow zone 21 and / or the second cross-flow zone 22 are arranged aligned to each other. The shown grid 15 comprises a plurality of holding structures 12, which are arranged in parallel to each other. Each holding structure 12 defines one recess for encompassing the outer edge 14 of one plate element of the first type 3 and the thereto-aligned outer edge of one plate element of the second type 4. The transversal ribs 16 bridging neighboring holding structures 12 are arranged perpendicular to the holding structures 12, thereby forming the grid 15 with rectangular orifices 33. The connection element 12 in form of a grid 15 is beneficial for a fast assembly process as well as providing additional stability for the stack 2 of plate elements 3, 4.

[0044] Figure 6 shows a perspective view on the stack 2 according to Figure 5 with a continuous layer of adhesive 18 being applied to the stack 2. The uncovered segments of the outer edges 14 are sealed by applying the adhesive 18 in form of a pasty adhesive and a foam adhesive, preferably in form of a continuous layer 28 of foam adhesive. Figure 7 shows a perspective view on the plate heat exchanger 1 being fully assembled and sealed by beads of adhesive 18, forming the self-contained and sealed subassembly 26. The connection element 11 is secured in position by applying a circumferential bead of adhesive 18 enclosing and sealing the connection element 11. The stack 2 of alternatingly arranged plate elements of the first type 3 and plate elements of a second type 4 with mounted connection element 11 forms the self-contained and sealed subassembly 26.

[0045] Figure 8 shows a perspective view on the plate heat exchanger being assembled with thereto mounted casing 27.The plate heat exchanger 1 is enclosed by assembling the additional casing 27, in the shown variation comprising side plates 29, a top plate 30 and a bottom plate 31.LIST OF DESIGNATIONS

[0046] 1Plate heat exchanger 2Stack 3First type plate elements 4Second type plate elements 5First flow path 6Second flow path 7First inlet 8First outlet 9Second inlet 10Second outlet 11Connection element 12Holding structure 13Recess 14Outer edge 15Grid 16Rib 17Guiding chamfer 18Adhesive 19Heat exchange plate 20Polymer layer 21First cross-flow zone 22Second cross-flow zone 23Intermediate zone 24Fluid-guiding rib 25Longitudinal rib 26Subassembly 27Casing 28Layer (Adhesive) 29Side plate (Casing) 30Top plate (Casing) 31Bottom Plate (Casing) 32Stacking device 33Orifice (grid) xLongitudinal axis

Claims

1. A plate heat exchanger (1) for heat exchange between at least two fluids, comprising: a. a stack (2) of alternatingly arranged plate elements of a first type (3) and plate elements of a second type (4), wherein i. the plate elements of the first type (3) and the plate elements of the second type (4) define alternatingly arranged first flow paths (5) and second flow paths (6) between each other, wherein ii. each first flow path (5) extends from a first inlet (7) to a first outlet (8) and each second flow path (6) extends from a second inlet (9) to a second outlet (10); b. a connection element (11) interconnecting the plate elements of the first type (3) and the plate elements of the second type (4) with each other by holding structures (12) each defining a recess (13), which encompasses superimposed outer edges (14) of neighboring plate elements of the first type (3) and of the second type (4) in the region of the first and second inlets (7, 9) and / or in the region of the first and second outlets (8, 10) and thereby providing a sealing connection between the plate elements of the first type (3) and of the second type (4) in the region of the first and second inlets (7, 9) and / or the first and second outlets (8, 10).

2. The plate heat exchanger (1) according to claim 1, wherein the connection element (11) is formed as a grid (15) comprising a plurality of holding structures (12) and transversal ribs (16) bridging neighboring holding structures (12).

3. The plate heat exchanger (1) according to claim 1 or 2, wherein the connection element (11) comprises a guiding chamfer (17) adjacent to an end of the recess (13), defining a gap being larger than a thickness of the neighboring plate elements (3, 4) in the region of the first and second inlets (7, 9) and / or in the region of the first and second outlets (8, 10), such that the connection element (11) is slideable over the outer edges (14).

4. The plate heat exchanger (1) according to any one of the preceding claims, wherein the connection element (11) is connected to the plate elements of the first (3) and second type (4) by an adhesive (18), preferably circumferentially and adjacent to the guiding chamfers (17).

5. The plate heat exchanger (1) according to any one of the preceding claims, wherein the plate heat exchanger (1) is an enthalpy heat exchanger, wherein preferably the plate elements of the first (3) and second type (4) each comprise a heat exchange plate (19) which is perforated or with an inherent pore structure, which is optionally on at least one side coated by a thin polymer layer (20) with water vapor transmission characteristics.

6. The plate heat exchanger (1) according to any one of the preceding claims, wherein the plate elements of the first (3) and second type (4) each extend along a longitudinal axis (x) and include a first cross-flow zone (21), a second cross-flow zone (22) and an intermediate zone (23) located along the longitudinal axis (x) between the first (21) and second cross-flow zones (22), wherein preferably at least one fluid-guiding rib (24) is arranged between the plate elements of the first (3) and second type (4) in the first cross-flow zone (21) and / or the second cross-flow zone (22) and preferably at least one longitudinal rib (25) is arranged in the intermediate zone (23) extending along the longitudinal axis (x).

7. The plate heat exchanger (1) according to claim 6, wherein the first and second inlets (7, 9) and / or first and second outlets (8, 10) are arranged inclined with respect to the longitudinal axis (x) and the at least one fluid-guiding rib (24) in the first cross-flow zone (21) and / or the second cross-flow zone (22) is arranged inclined with respect to the longitudinal axis (x), preferably perpendicular to the first and second inlets (7, 9) and / or first and second outlets (8, 10).

8. The plate heat exchanger (1) according to claim 2 and 7, wherein in a top view on the connection element (11) the transversal ribs (16) of the connection element (11) and the fluid-guiding rib (24) in the first cross-flow zone (21) and / or the second cross-flow zone (22) are arranged aligned to each other.

9. The plate heat exchanger (1) according to any one of the preceding claims, wherein the stack (2) of alternatingly arranged plate elements of the first type (3) and plate elements of a second type (4) with mounted connection element (11) forms a self-contained and sealed subassembly (26).

10. The plate heat exchanger (1) according to any one of the preceding claims, wherein the plate heat exchanger (1) is accommodated in an additional casing (27), in particular a separate casing.

11. Method for providing a plate heat exchanger (1) according to one of the preceding claims, comprising at least the following method steps: a. Providing a number of plate elements of the first type (3) and plate elements of a second type (4); b. Forming a stack (2) of alternatingly arranged plate elements of the first type (3) and plate elements of the second type (4) such that the plate elements (3, 4) define alternatingly arranged first flow paths (5) and second flow paths (6) with each first flow path (5) extending from a first inlet (7) to a first outlet (8) and each second flow path (6) extending from a second inlet (9) to a second outlet (10); c. Arranging a connection element (11) in the region of the first and second inlets (7, 9) and / or in the region of the first and second outlets (8, 10) of the plate elements of the first type (3) and of the second type (4) by sliding the connection element (11) onto the outer edges (14) such that the recess (13) encompasses the superimposed outer edges (14) of neighboring plate elements of the first type (3) and of the second type (4).

12. The method according to claim 11, wherein after arranging the connection element (11) in the region of the first and second inlets (7, 9) and / or in the region of the first and second outlets (8, 10) of the plate elements of the first type (3) and of the second type (4), the connection element (11) is secured in position by applying a circumferential bead of adhesive (18) enclosing and sealing the connection element (11).

13. The method according to claim 11 or 12, wherein after arranging the connection element (11) in the region of the first and second inlets (7, 9) and / or in the region of the first and second outlets (8, 10) of the plate elements of the first type (3) and of the second type (4), the uncovered segments of the outer edges (14) are sealed by applying an adhesive (18), in particular a bead of adhesive, wherein preferably the uncovered segments of the outer edges (14) are sealed by applying the adhesive (18) in form of a pasty adhesive and / or a foam adhesive, preferably in form of a continuous layer (28) of foam adhesive.

14. The method according to any one of claims 11 to 13, wherein the plate heat exchanger (1) is enclosed by assembling the additional casing (27), preferably comprising side plates (29), a top plate (30) and a bottom plate (31).

15. The method according to any one of claims 11 to 14, wherein for forming the stack (2), the plate elements of the first type (3) and of the second type (4) are alternatingly placed in a stacking device (32) until the connection element (11) is mounted and the plate heat exchanger (1) forms a self-contained and sealed assembly.

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