Plate heat exchanger

Abstract

A plate heat exchanger, which comprises a plate pack formed of elongated rectangular heat exchanger plates for providing an improved heat exchange efficiency. The heat exchanger plates (1) comprises a rounded first end (2a) and a rounded second end (2b) in a length direction5 of the heat exchanger plate, and the heat exchanger plate (1) comprises a first opening (3a) and a second opening (3b) for a heat exchange medium, which openings of the heat exchanger plate are arranged at the first end of the heat exchanger plate. The heat0 exchanger plate (1) further comprises a barrier structure (4) arranged between the first opening (3a) and the second opening (3b), which barrier structure divides a surface of the heat exchanger plate to two distinct partitions. The structure of the heat exchanger plates5 forces a heat exchange medium to flow U-path inside the plate pack.

Description

[0001] PLATE HEAT EXCHANGER

[0002] Field of the invention

[0003] The present invention relates to a plate heat exchanger according to the claims presented below.

[0004] Background of the invention

[0005] Plate and Shell -type heat exchangers are composed of a plate pack formed by heat exchange plates and an outer casing surrounding it, functioning as a pressure vessel. A plate pack is typically composed of circular heat exchanger plates, where the plates have been welded tightly together at openings therein and / or at the perimeters of the plates. A primary circuit of the heat exchanger is formed between the openings in the plates, and a secondary circuit between connections of the outer casing surrounding the plate pack, so that a primary side flow medium flows in every other plate space of the plate pack and a secondary side flow medium in every other plate space. In some cases, a plate pack can be formed of elongated rectangular heat exchanger plates. Plate and Shell heat exchangers can be used in many different applications.

[0006] Especially in heat exchangers, which are used to recover heat from gases, it is desirable to achieve an efficient heat exchange for plate pack side without increasing the pressure loss in the shell side of the heat exchanger.

[0007] Summary of the Invention

[0008] It is an object of the invention to provide a plate heat exchanger with a novel structure which improves heat exchange efficiency and utilizes the whole area of the heat exchanger plates more efficiently.

[0009] Further, it is an object of the present invention to provide a plate heat exchanger, which provides an efficient heat exchange for plate pack side without increasing the pressure loss in the shell side of the heat exchanger. In order to achieve among others the objects presented above, the invention is characterized by what is presented in the characterizing parts of the enclosed independent claims.

[0010] The embodiments and advantages mentioned in this text relate, where applicable, both to the heat exchanger plate, the plate pack as well as to the plate heat exchanger according to the invention, even though it is not always specifically mentioned.

[0011] Some preferred embodiments of the invention will be described in the other claims.

[0012] Typical plate heat exchanger according to the present invention comprises

[0013] - an outer casing, which comprises a shell and a first end plate and a second end plate arranged at the ends of the shell,

[0014] - a plate pack arranged inside the outer casing, which plate pack is formed of the heat exchanger plates stacked on top of each other, in which plate pack the heat exchanger plates are attached to each other as plate pairs,

[0015] - an inlet connection and an outlet connection arranged at an end plate of the outer casing for a heat exchange medium to lead a heat exchange medium into the plate pack and out from it, and

[0016] - an inlet connection and an outlet connection arranged through the outer casing for a heat exchange medium flowing in the shell side, and the heat exchanger plates of the plate pack are an elongated rectangular heat exchanger plates having a rounded first end and a rounded second end in a length direction of the heat exchanger plate, and the heat exchanger plates comprise

[0017] - a first opening and a second opening for a heat exchange medium, which first opening and second opening of the heat exchanger plate are arranged at the first end of the heat exchanger plate, and

[0018] - a barrier structure arranged between the first opening and the second opening, which barrier structure divides a surface of the heat exchanger plate to two distinct partitions, and the barrier structure elongates from the first end of the heat exchanger plate comprising the first and second openings towards the second end of the heat exchanger plate in the length direction of the heat exchanger plate. A plate heat exchanger according to the present invention is Plate and Shell - type heat exchanger. A heat exchanger plates used in the plate heat exchanger according to the present invention is designed to improve the heat exchange efficiency of the plate heat exchanger. The heat exchanger plate provides a longer flow path for a heat exchange medium inside the plate pack, and thus the whole area of the heat exchanger plates can be better utilised to the heat exchange. This is especially advantageous in heat exchanger for use in recovering heat from gas flows. The longer flow path of the heat exchange medium is obtained by arranging the openings of the heat exchanger plate to the same end of the elongated heat exchanger plate and forming a barrier structure on the surface of the heat exchange plate between the openings, typically in the middle of the heat exchanger plate. Thus, a heat exchange medium has to flow a certain longer flow path when it flows from the first opening to the second opening of the heat exchanger plate in the plate pack. Thus, a heat exchange medium is forced to flow ll-path inside the plate pack. A flow path inside the plate pack is longer in compared to the flow in the shell side in the heat exchanger according to the invention.

[0019] The present invention also provides a compact structure of the plate heat exchanger since the inlet and outlet connections of the plate pack are arranged to the same end plate of the plate heat exchanger.

[0020] A plate heat exchanger according to the present invention can be especially used in applications with gas flow, such as heat recovery from exhaust gas. A plate heat exchanger according to the present invention can also be utilised in heat recovery in other applications.

[0021] Description of the drawings

[0022] The invention will be described in more detail with reference to appended drawings, in which

[0023] Fig.1 shows a heat exchanger plate according to an embodiment of the plate heat exchanger of the present invention,

[0024] Fig. 2 shows a structure of the plate pack according to an embodiment of plate heat exchanger of the present invention, Fig. 3 shows a structure of the plate heat exchanger according to an embodiment of the present invention by illustrating a plate pack inside the outer casing, the flow paths of the heat exchange media are presented by arrows, and

[0025] Fig. 4 shows the plate heat exchanger according to an embodiment of the present invention from outside.

[0026] Detailed description of the invention

[0027] In a plate heat exchanger according to the present invention, a plate pack is formed of the heat exchanger plates, which are elongated rectangular heat exchanger plates having a rounded first end and a rounded second end in a length direction of the heat exchanger plate. The rounded ends mean that the comers of the rectangular plate are rounded. The heat exchanger plate has a length direction, which is a length from the rounded first end to the rounded second end. A width direction of the heat exchanger plate is perpendicular to the length direction of the heat exchanger plate. In a typical embodiment of the present invention, a width of the elongated rectangular heat exchanger plate is smaller than the length of the heat exchanger plate. According to an embodiment of the present invention, a ratio of the width and the length of the heat exchanger plate can be varied in the range of 1 :1 .2 - 1 :10.

[0028] The elongated rectangular heat exchanger plates comprise a first opening and a second opening for a heat exchange medium, which first opening and second opening of the heat exchanger plate are arranged at the same end of the heat exchanger plate. Typically, the first opening and the second opening are arranged next to each other in the width direction of the heat exchanger plate. In this description, the end comprising the first opening and the second opening for a heat exchanger medium is named as the first end of the heat exchanger plate. According to an embodiment of the present invention, a second end of the heat exchanger plate is free of the openings for a heat exchanger medium.

[0029] The elongated rectangular heat exchanger plates have planar surfaces, which comprise a surface pattern formed of grooves and ridges. The surface pattern is on both planar surfaces of the heat exchanger plate. In a elongated rectangular heat exchanger plate used in a plate heat exchanger according to the present invention, a barrier structure has been arranged on a surface of the heat exchanger plate between the first opening and the second opening of the heat exchanger plate for dividing the surface of the heat exchanger plate to two distinct partitions, whereby a surface pattern formed on the planar surface of the heat exchanger plate is not uniformly arranged to the whole area of the heat exchanger plate, but the barrier structure splits the surface partly to two partitions. The barrier structure has been arranged to elongate from the first end of the heat exchanger plate comprising the first and second openings towards the second end of the heat exchanger plate in the length direction of the heat exchanger plate. However, the barrier structure does not split the whole heat exchanger plate in the length direction of the heat exchanger plate, but the second end, which does not comprise the openings for the heat exchanger medium, is formed to comprise uniformly arranged pattern of the heat exchanger plate, without any barrier structure. In an embodiment according to the present invention, a barrier structure is arranged to elongate from the first end at least to the middle of the heat exchanger plate in the length direction of plate. More typically a barrier structure is arranged to elongate from the first end to over the middle of the heat exchanger plate in the length direction of the plate, and even more typically the length of the barrier structure is about 3 / 4 of the length of the heat exchanger plate in its length direction. According to an embodiment of the present invention, at least 1 / 4 of the length of the heat exchanger plate in its length direction does not include the barrier structure.

[0030] A barrier structure is typically arranged only at one surface of the heat exchanger plate between the first opening and the second opening of the heat exchanger plate for dividing the surface of the heat exchanger plate to two distinct partitions, as described above. When the heat exchanger plates are stacked to each other, the barrier structures form the barrier between the heat exchanger plates and thereby guides a flow path of the heat exchanger medium between the plates to flow ll-path inside the plate pack, i.e. in the plate pack side. Thus, the heat exchanger plate used in a plate heat exchanger according to the present invention makes possible to construct plate packs which have a certain flow pattern of the heat exchanger medium inside the plate pack. In an embodiment according to the present invention, the barrier structure is arranged substantially in the middle of the heat exchanger plate in a width direction of the heat exchanger plate.

[0031] According to the present invention, the barrier structure may comprise a surface pattern or the like formed into a surface of the heat exchanger plate, a protrusion formed and / or attached to the heat exchanger plate, a weld joint, and / or a gasket. The aim of the barrier structure is to block the flow of the heat exchange medium from one side of the heat exchanger plate to the other side of the heat exchanger plate in the width direction of the plate and thus forces the heat exchange medium to flow ll-path.

[0032] A plate pack used in a plate heat exchanger according to the present invention has been formed of the stack of the heat exchanger plates. The stack of the plates defines the height direction of the plate pack. A plate pack comprises elongated rectangular heat exchanger plates. In a preferred embodiment of the present invention, the stack of the plates, i.e. plate pack has been formed of the heat exchanger elongated rectangular plates in such a manner that the barrier structures of the heat exchanger plates are arranged one against the other, whereby the barrier structures are in every other plate space of the plate pack, and every other plate space in the plate pack is thus free of the barrier structures. Every other plate space in the plate pack is free of the barrier structures, which means that there are no barrier structures in the shell side of the heat exchanger. The plate pack according to the present invention is used in Plate and Shell -type heat exchangers.

[0033] Plate and Shell -type heat exchangers comprise an outer casing and a plate pack arranged inside the outer casing. An outer casing comprises a shell and a first end plate and a second end plate, which are arranged at the ends of the shell. In a typical embodiment the shell is a cylindrical shell. In another embodiment according to the present invention, an outer casing may be a part of a flow channel, and the plate pack is arranged inside the flow channel.

[0034] A plate pack used in a plate heat exchanger according to the present invention is formed by arranging plate pairs on top of each other. Each plate pair is typically formed of two heat exchanger plates that are attached, preferably welded together at least at their outer periphery. Each heat exchanger plate has two openings for the flow of a heat exchange medium. Adjacent plate pairs are attached to each other by attaching the openings of two adjacent plate pairs to each other. Thus, a heat exchange medium can flow from a plate pair to another via the openings. The barrier structures in the heat exchanger plates according to the invention forces a heat exchange medium to flow ll-path inside the plate pair, i.e. in the plate pack side of the heat exchanger.

[0035] In the plate pack used in the plate heat exchanger according to the present invention, the barrier structure is typically arranged only at the plate pack side. The barrier structure is not arranged to the plate space of the heat exchanger plates, where a heat exchange medium of the shell side is flown, and thus the pressure loss is not increased. The plate pack formed of the elongated rectangular heat exchanger plates provides a short flow path through the plate pack for a heat exchange medium in the shell side, since the plate pack is arranged to the heat exchanger in such a manner that the length direction of the elongated rectangular heat exchanger plates is perpendicular to the flow direction of the heat exchanger medium in the shell side of the heat exchanger.

[0036] An inlet connection and an outlet connection for a heat exchange medium for leading a heat exchange medium into the plate pack and out from it are arranged at an end plate of the outer casing. The inlet and outlet connection for the heat exchange medium are arranged in connection with the inner parts of the plate pack, i.e. inner parts of the plate pairs of the plate pack, whereby the primary circuit of the heat exchanger is formed between the inlet and outlet connection of the plate pack. The primary circuit is called as plate pack side of the heat exchanger. The inlet and outlet connections for other heat exchange medium are arranged in connection with the inner side of the outer casing, i.e. with the outer side of the pack of plates. In other words, the secondary circuit of the heat exchanger is formed between the inlet and outlet connection of the shell side, inside the outer casing, in the spaces between the plate pairs. The inlet and outlet connections are typically arranged through the outer casing. The secondary circuit is called as shell side of the heat exchanger. The primary and secondary circuits are separate from each other, i.e. the heat exchange medium flowing in the inner part of the plate pack cannot get mixed with the other heat exchange medium flowing in the outer casing. Thus, the heat exchange medium of the plate pack side flows in every other plate space and the heat exchange medium of the shell side flows in every other plate space of the plate pack.

[0037] In a plate heat exchanger according to the invention, an inlet connection and an outlet connection for a heat exchange medium in the shell side are typically arranged through a cylindrical shell of the outer casing. A heat exchanger medium of the shell side flows through the plate pack in width direction of the plate pack. A width direction of the plate pack corresponds with the width direction of the heat exchanger plates. The width direction of the plate pack is perpendicular to the length direction of the plate pack and the heat exchanger plates.

[0038] Detailed description of the drawings

[0039] Figure 1 shows a heat exchanger plate 1 used in a plate heat exchanger according to an embodiment of the present invention. The heat exchanger plate 1 is an elongated rectangular heat exchanger plate having a rounded first end 2a and a rounded second end 2b in a length direction A of the heat exchanger plate. The heat exchanger plate 1 comprises a first opening 3a and a second opening 3b for a heat exchange medium, which first opening and second opening of the heat exchanger plate are arranged at the first end 2a of the heat exchanger plate. The first opening 3a and the second opening 3b of the heat exchanger plate are arranged next to each other in the width direction of the heat exchanger plate. A barrier structure 4 has been arranged between the first opening 3a and the second opening 3b in the middle of the plate in the width direction B of the heat exchanger plate. The barrier structure divides a surface pattern of the heat exchanger plate 1 to two distinct partitions. The barrier structure elongates from the first end 2a of the heat exchanger plate comprising the first and second openings towards the second end 2b of the heat exchanger plate in the length direction A of the heat exchanger plate. In an embodiment presented in Figure 1 , the length of the barrier structure is about 3 / 4 of the length of the heat exchanger plate in its length direction A. Thus, about 1 / 4 of the length of the heat exchanger plate in its length direction A does not include the barrier structure. The second end 2b of the heat exchanger plate comprises uniformly arranged pattern of the heat exchanger plate, without any barrier structure. Figure 2 shows a structure of the plate pack 5 relating to a plate heat exchanger according to an embodiment of the present invention. The plate pack 5 has been formed of the stack of the heat exchanger plates. The plate pack comprises elongated rectangular heat exchanger plates 1 according to the present invention. The plate pack 5 has been formed of the heat exchanger plates according to the present invention in such a manner that the barrier structures of the heat exchanger plates are arranged one against the other, whereby the barrier structures are in every other plate space of the plate pack, and every other plate space in the plate pack is thus free of the barrier structures. The inlet connection 6a and outlet connection 6b for guiding a heat exchange medium inside and out from the plate pack 5 are attached to the openings of the uppermost heat exchanger plate of the plate pack.

[0040] Figure 3 shows a structure of the plate heat exchanger 7 according to an embodiment of the present invention. Plate pack 5 is arranged inside the outer casing 8. The outer casing comprises an inlet connection 9a and an outlet connection 9b for a heat exchange medium flowing in the shell side of the heat exchanger. The plate pack 5 is arranged to the heat exchanger in such a manner that the length direction of the elongated rectangular heat exchanger plates is perpendicular to the flow direction of the heat exchange medium flowing in the shell side of the heat exchanger. Thus, the plate pack formed of the elongated rectangular heat exchanger plates provides a short flow path through the plate pack for a heat exchange medium in the shell side.

[0041] In Figure 3, it is also illustrated by the arrows the flow paths of the heat exchange media in the shell side and in the plate pack side. The barrier structure in the heat exchanger plates according to the invention forces a heat exchanger medium to flow ll-path inside the plate pairs of the plate pack, i.e. in the plate pack side. The heat exchange medium in the shell side can flow directly though the plate pack since the plate spaces open to the shell side do not include any barrier structures.

[0042] Figure 4 illustrates the plate heat exchanger according to an embodiment of the present invention from outside. The inlet connection 6a and the outlet connection 6b for a heat exchange medium for leading a heat exchange medium into the plate pack and out from it are arranged at the same end plate of the outer casing 8.

Claims

Claims1 . A plate heat exchanger (7), which comprises- an outer casing (8), which comprises a shell and a first end plate and a second end plate arranged at the ends of the shell,- a plate pack (5) arranged inside the outer casing, which plate pack is formed of the heat exchanger plates (1 ) stacked on top of each other, in which plate pack the heat exchanger plates are attached to each other as plate pairs,- an inlet connection (6a) and an outlet connection (6b) arranged at an end plate of the outer casing for a heat exchange medium to lead a heat exchange medium into the plate pack and out from it, and- an inlet connection (9a) and an outlet connection (9b) arranged through the outer casing for a heat exchange medium flowing in the shell side, characterized in that the heat exchanger plates (1 ) of the plate pack (5) are elongated rectangular heat exchanger plates having a rounded first end (2a) and a rounded second end (2b) in a length direction of the heat exchanger plate, and the heat exchanger plates (1 ) comprise- a first opening (3a) and a second opening (3b) for a heat exchange medium, which first opening and second opening of the heat exchanger plate are arranged at the first end of the heat exchanger plate, and- a barrier structure (4) arranged between the first opening (3a) and the second opening (3b), which barrier structure divides a surface of the heat exchanger plate to two distinct partitions, and the barrier structure elongates from the first end of the heat exchanger plate comprising the first and second openings towards the second end of the heat exchanger plate in the length direction of the heat exchanger plate.

2. The plate heat exchanger according to claim 1 , characterized in that the second end (2b) of the heat exchanger plate is free of the openings for a heat exchanger medium.

3. The plate heat exchanger according to claim 1 or 2, characterized in that the barrier structure (4) is arranged in the middle of the heat exchanger plate in a width direction of the heat exchanger plate.

4. The plate heat exchanger according to any one of the preceding claims, characterized in that the barrier structure (4) comprises a surface pattern formed into the surface of the heat exchanger plate, a protrusion formed and / or attached to the heat exchanger plate, a weld joint, and / or a gasket.

5. The plate heat exchanger according to any one of the preceding claims, characterized in that the barrier structure (4) has been formed only at one surface of the heat exchanger plate.

6. The plate heat exchanger according to any one of the preceding claims, characterized in that the surface of the heat exchanger plate (1 ) comprises a surface pattern formed of grooves and ridges.

7. The plate heat exchanger according to any one of the preceding claims, characterized in that a ratio of the width and the length of the heat exchanger plate (1 ) is 1 : 1 .2 - 1 : 10.

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