Plate package using a heat exchanger plate with integrated draining channel and a heat exchanger including such plate package

Abstract

A plate package for a heat exchanger device includes a plurality of heat exchanger plates of a first type and a plurality of heat exchanger plates of a second type. At least the heat exchanger plates of the first type include, along at least a section of the opposing side portions, a draining channel flange. The draining channel flanges are oriented in one and the same direction such that a draining channel flange of a first heat exchanger plate of the first type abuts or overlaps a draining channel flange of a subsequent heat exchanger plate. The draining channel flanges form outer walls to the outer draining portions thereby transforming the outer draining portions into draining channels. A method of using such plate package in a heat exchanger device and also a heat exchanger device as such are also disclosed.

Claims

1. A plate package for a heat exchanger device, comprising: a plurality of first heat exchanger plates; and a plurality of second heat exchanger plates arranged alternatingly in the plate package, one on top of another in a first direction, wherein each of the first and second heat exchanger plates have a geometrical main extension plane, and form first plate interspaces arranged to permit a flow of a medium to be evaporated there through, and second plate interspaces arranged to permit a flow of a fluid for evaporating the medium, wherein each of the first and second heat exchanger plates has a circumferential edge portion having an upper portion, a lower portion and two opposing side portions interconnecting the upper and lower portions, wherein each of the first and second heat exchanger plates further comprise, along at least a section of the opposing side portions, mating abutment portions extending along and at a distance from the circumferential edge portion, thereby separating each of the first plate interspaces into an inner heat transferring portion and two outer draining portions, wherein at least the first heat exchanger plates further comprise, along at least a section of the opposing side portions, draining channel flanges extending from the circumferential edge portion in a direction from the geometrical main extension plane, wherein the draining channel flanges of the first heat exchanger plates are oriented in a same direction, and have an extension with a component in the first direction such that the components of adjacent draining channel flanges of the first heat exchanger plates abut or overlap each other in a second direction perpendicular to the first direction, wherein the mating abutment portions form inner walls and the draining channel flanges form outer walls to the outer draining portions thereby transforming the outer draining portions into draining channels, and wherein each of the draining channels has an inlet opening between an upper end of the draining channel flange and the upper portion of the circumferential edge portion, said inlet opening having a mouth having a generally horizontal extension and an outlet opening at a lower end of the mating abutment portions facing the lower portion of the circumferential edge portion.

2. The plate package according to claim 1, wherein the mating abutment portions are formed: by ridges formed in the first heat exchanger plates and in the second heat exchanger plates; or by one of the first or second heat exchanger plates comprising a ridge and another one of the first or second heat exchanger plates comprising an essentially flat surface.

3. The plate package according to claim 2, wherein each of the draining channels, as seen in a cross section transverse to a longitudinal extension thereof, is defined by a draining channel flange, an outer draining portion and an abutment portion of one of the first heat exchanger plates and by an abutment portion and an outer draining portion of an adjacent second heat exchanger plate.

4. The plate package according to claim 2, wherein a respective draining channel, as seen in a cross section transverse to a longitudinal extension thereof, has a uniform cross-sectional geometry along said longitudinal extension.

5. The plate package according to claim 2, wherein the abutment portions of a respective first heat exchanger plate sealingly abut the abutment portions of a respective second heat exchanger plate.

6. The plate package according to claim 1, wherein each of the draining channels, as seen in a cross section transverse to a longitudinal extension thereof, is defined by a draining channel flange, an outer draining portion and an abutment portion of one of the first heat exchanger plates and by an abutment portion and an outer draining portion of an adjacent second heat exchanger plate.

7. The plate package according to claim 6, wherein a respective draining channel, as seen in a cross section transverse to a longitudinal extension thereof, has a uniform cross-sectional geometry along said longitudinal extension.

8. The plate package according to claim 6, wherein the abutment portions of a respective first heat exchanger plate sealingly abut the abutment portions of a respective second heat exchanger plate.

9. The plate package according to claim 1, wherein a respective draining channel, as seen in a cross section transverse to a longitudinal extension thereof, has a uniform cross-sectional geometry along said longitudinal extension.

10. The plate package according to claim 9, wherein the abutment portions of a respective first heat exchanger plate sealingly abut the abutment portions of a respective second heat exchanger plate.

11. The plate package according to claim 1, wherein the abutment portions of a respective first heat exchanger plate sealingly abut the abutment portions of a respective second heat exchanger plate.

12. The plate package according to claim 1, wherein a lower portion of the draining channel flange extends past a transition between the side portion and the lower portion of the circumferential edge portion.

13. The plate package according to claim 1, wherein the upper portion of each heat exchanger plate is curved and the lower portion of each heat exchanger plate is substantially straight, and wherein a first porthole is arranged in a lower section of each heat exchanger plate and located at a distance from the lower portion of the circumferential edge portion thereby defining a first intermediate portion located between the lower substantially straight portion of the circumferential edge portion and a circumferential edge of the first porthole, the first intermediate portion including a shortest distance between a centre of the first porthole and the lower portion of the circumferential edge portion, wherein a second porthole is arranged in an upper section of the heat exchanger plate and located at a distance from the upper portion of the circumferential edge portion thereby defining a second intermediate portion located between the upper portion of the circumferential edge portion and a circumferential edge of the second porthole, the second intermediate portion including a shortest distance between a centre of the second porthole and the upper portion of the circumferential edge portion, wherein a first shielding flange is arranged along at least a section of the first intermediate portion and having an extension along the lower portion of the circumferential edge portion, and said first shielding flange having a length as seen in a direction transverse the shortest distance between a centre of the first porthole and the lower portion of the circumferential edge portion, being smaller than the diameter of the first porthole, and/or wherein a second shielding flange is arranged along at least a section of the second intermediate portion and having an extension along the upper portion of the circumferential edge portion and said second shielding flange having a length as seen in a direction transverse the shortest distance between a centre of the second porthole and the upper portion of the circumferential edge portion, being 200-80% of the diameter of the second porthole.

14. The plate package according to claim 1, wherein the upper portion of each heat exchanger plate is curved and the lower portion of each heat exchanger plate is substantially straight, and wherein a first porthole is arranged in a lower section of each heat exchanger plate and located at a distance from the lower portion of the circumferential edge portion thereby defining a first intermediate portion located between the lower substantially straight portion of the circumferential edge portion and a circumferential edge of the first porthole, the first intermediate portion including a shortest distance between a centre of the first porthole and the lower portion of the circumferential edge portion, wherein a second porthole is arranged in an upper section of the heat exchanger plate and located at a distance from the upper portion of the circumferential edge portion thereby defining a second intermediate portion located between the upper portion of the circumferential edge portion and a circumferential edge of the second porthole, the second intermediate portion including a shortest distance between a centre of the second porthole and the upper portion of the circumferential edge portion, wherein a first shielding flange is arranged along at least a section of the first intermediate portion and having an extension along the lower portion of the circumferential edge portion, and said first shielding flange having a length as seen in a direction transverse the shortest distance between a centre of the first porthole and the lower portion of the circumferential edge portion, being smaller than 80% of the diameter of the first porthole, and/or wherein a second shielding flange is arranged along at least a section of the second intermediate portion and having an extension along the upper portion of the circumferential edge portion and said second shielding flange having a length as seen in a direction transverse the shortest distance between a centre of the second porthole and the upper portion of the circumferential edge portion, being 180-120% of the diameter of the second porthole.

15. The plate package according to claim 1, wherein each abutment portion comprises at least one ridge extending along one of the side portions and along the upper portion.

16. A method comprising using the plate package according to claim 1 in a heat exchanger device.

17. A heat exchanger device, comprising: a shell forming a substantially closed inner space and including an inner wall surface facing the inner space, said heat exchanger device being arranged to include a plate package, said plate package including: a plurality of first heat exchanger plates and a plurality of second heat exchanger plates arranged alternatingly in the plate package, one on top of another in a first direction, wherein each of the first and second heat exchanger plates have a geometrical main extension plane and is provided in such a way that the main extension plane is substantially vertical, and form first plate interspaces which are substantially open towards the inner space and arranged to permit circulation of a medium to be evaporated from a lower part of the inner space upwardly to an upper part of the inner space, and second plate interspaces, which are closed to the inner space and arranged to permit flow of a fluid for evaporating the medium, wherein each of the first and second heat exchanger plates has a circumferential edge portion having an upper portion, a lower portion and two opposing side portions interconnecting the upper and lower portions, wherein each of the first and second heat exchanger plates further comprise, along at least a section of the opposing side portions, mating abutment portions extending along and at a distance from the circumferential edge portion, thereby separating each of the first plate interspaces into an inner heat transferring portion and two outer draining portions, wherein at least the first heat exchanger plates further comprise, along at least a section of the opposing side portions, draining channel flanges extending from the circumferential edge portion in a direction from the geometrical main extension plane, wherein the draining channel flanges of the first heat exchanger plates are oriented in a same direction, and have an extension with a component in the first direction such that the components of adjacent draining channel flanges of the first heat exchanger plates abut or overlap each other in a second direction perpendicular to the first direction, wherein the mating abutment portions form inner walls and the draining channel flanges form outer walls to the outer draining portions thereby transforming the outer draining portions into draining channels, and wherein each of the draining channels has an inlet opening between an upper end of the draining channel flange and the upper portion of the circumferential edge portion, said inlet opening having a mouth having a generally horizontal extension and an outlet opening at a lower end of the mating abutment portions facing the lower portion of the circumferential edge portion.

18. The heat exchanger device according to claim 17, wherein each abutment portion comprises at least one ridge extending along one of the side portions and along the upper portion.

19. A plate package for a heat exchanger device, comprising: a plurality of first heat exchanger plates; and a plurality of second heat exchanger plates arranged alternatingly in the plate package, one on top of another in a first direction, wherein each of the first and second heat exchanger plates have a geometrical main extension plane, and form first plate interspaces arranged to permit a flow of a medium to be evaporated there through, and second plate interspaces arranged to permit a flow of a fluid for evaporating the medium, wherein each of the first and second heat exchanger plates has a circumferential edge portion having an upper portion, a lower portion and two opposing side portions interconnecting the upper and lower portions, wherein each of the first and second heat exchanger plates further comprise, along at least a section of the opposing side portions, mating abutment portions extending along and at a distance from the circumferential edge portion, thereby separating each of the first plate interspaces into an inner heat transferring portion and two outer draining portions, wherein both of the first heat exchanger plates and the second heat exchanger plates further comprise, along at least a section of the opposing side portions, draining channel flanges extending from the circumferential edge portion in a direction from the geometrical main extension plane, wherein the draining channel flanges of the first and second heat exchanger plates are oriented in a same direction, and have an extension with a component in the first direction such that the components of adjacent draining channel flanges abut or overlap each other in a second direction perpendicular to the first direction, wherein the draining channel flanges form outer walls to the outer draining portions thereby transforming the outer draining portions into draining channels, and wherein each of the draining channels has an inlet opening between the upper end of the draining channel flange and the upper portion of the circumferential edge portion, said inlet opening having a mouth having a generally horizontal extension and an outlet opening a lower end of the mating abutment portions facing the lower portion of the circumferential edge portion.

20. The plate package according to claim 19, wherein each abutment portion comprises at least one ridge extending along one of the side portions and along the upper portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will by way of example be described in more detail with reference to the appended schematic drawings, which show a presently preferred embodiment of the invention.

(2) FIG. 1 discloses a schematically and sectional view from the side of a heat exchanger device of the plate-and-shell type.

(3) FIG. 2 discloses schematically another sectional view of the heat exchanger device of FIG. 1.

(4) FIG. 3 discloses a heat exchanger plate.

(5) FIG. 4 discloses a cross section of a plate package comprising heat exchanger plates of the type disclosed in FIG. 3.

(6) FIG. 5 discloses a cross section of the plate package as seen transverse the first shielding flange.

(7) FIG. 6 discloses a schematic cross section of a heat exchanger device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(8) Referring to FIGS. 1 and 2, a schematic cross section of a typical heat exchanger device of the plate-and-shell type is disclosed. The heat exchanger device includes a shell 1, which forms a substantially closed inner space 2. In the embodiment disclosed, the shell 1 has a substantially cylindrical shape with a substantially cylindrical shell wall 3, see FIG. 1, and two substantially plane end walls (as shown in FIG. 2). The end walls may also have a semi-spherical shape, for instance. Also other shapes of the shell 1 are possible. The shell 1 comprises a cylindrical inner wall surface 3 facing the inner space 2. A sectional plane p extends through the shell 1 and the inner space 2. The shell 1 is arranged to be provided in such a way that the sectional plane p is substantially vertical. The shell 1 may by way of example be of carbon steel.

(9) The shell 1 includes an inlet 5 for the supply of a two-phase medium in a liquid state to the inner space 2, and an outlet 6 for the discharge of the medium in a gaseous state from the inner space 2. The inlet 5 includes an inlet conduit which ends in a lower part space 2′ of the inner space 2. The outlet 6 includes an outlet conduit, which extends from an upper part space 2″ of the inner space 2. In applications for generation of cold, the medium may by way of example be ammonia.

(10) The heat exchanger device includes a plate package 200, which is provided in the inner space 2 and includes a plurality of heat exchanger plates 100 provided adjacent to each other. The heat exchanger plates 100, are discussed in more detail in the following with reference in FIG. 3. The heat exchanger plates 100 are permanently connected to each other in the plate package 200, for instance through welding, brazing such as copper brazing, fusion bonding, or gluing. Welding, brazing and gluing are well-known techniques and fusion bonding can be performed as described in WO 2013/144251 A1. The heat exchanger plates 100 may be made of a metallic material, such as a iron, nickel, titanium, aluminum, copper or cobalt based material, i.e. a metallic material (e.g. alloy) having iron, nickel, titanium, aluminum, copper or cobalt as the main constituent. Iron, nickel, titanium, aluminum, copper or cobalt may be the main constituent and thus be the constituent with the greatest percentage by weight. The metallic material may have a content of iron, nickel, titanium, aluminum, copper or cobalt of at least 30% by weight, such as at least 50% by weight, such as at least 70% by weight. The heat exchanger plates 100 are preferably manufactured in a corrosion resistant material, for instance stainless steel or titanium.

(11) Each heat exchanger plate 100 has a main extension plane q and is provided in such a way in the plate package 200 and in the shell 1 that the extension plane q is substantially vertical and substantially perpendicular to the sectional plane p. The sectional plane p also extends transversally through each heat exchanger plate 100. In the embodiment disclosed, the sectional plane p also thus forms a vertical centre plane through each individual heat exchanger plate 100.

(12) The heat exchanger plates 100 form in the plate package 200 first interspaces 12, which are open towards inner space 2, and second plate interspaces 13, which are closed towards the inner space 2. The medium mentioned above, which is supplied to the shell 1 via the inlet 5, thus pass into the plate package 200 and into the first plate interspaces 12.

(13) Each heat exchanger plate 100 includes a first port opening 107 and a second port opening 108. The first port openings 107 form an inlet channel connected to an inlet conduit 16. The second port openings 108 form an outlet channel connected to an outlet conduit 17. It may be noted that in an alternative configuration, the first port openings 107 form an outlet channel and the second port openings 108 form an inlet channel. The sectional plane p extends through both the first port opening 107 and the second port opening 108. The heat exchanger plates 100 are connected to each other around the port openings 107 and 108 in such a way that the inlet channel and the outlet channel are closed in relation to the first plate interspaces 12 but open in relation to the second plate interspaces 13. A fluid may thus be supplied to the second plate interspaces 13 via the inlet conduit 16 and the associated inlet channel formed by the first port openings 107, and discharged from the second plate interspaces 13 via the outlet channel formed by the second port openings 108 and the outlet conduit 17.

(14) As is shown in FIG. 1, the plate package 200 has an upper side and a lower side, and two opposite transverse sides. The plate package 200 is provided in the inner space 2 in such a way that it substantially is located in the lower part space 2′ and that a collection space 18 is formed beneath the plate package 200 between the lower side of the plate package and the bottom portion of the inner wall surface 3.

(15) Furthermore, recirculation channels 19 are formed at each side of the plate package 200. These may be formed by gaps between the inner wall surface 3 and the respective transverse side or as internal recirculation channels formed within the plate package 10.

(16) Each heat exchanger plate 100 includes a circumferential edge portion 20 which extends around substantially the whole heat exchanger plate 100 and which permits said permanent connection of the heat exchanger plates 100 to each other. These circumferential edge portions 20 will along the transverse sides abut the inner cylindrical wall surface 3 of the shell 1. The recirculation channels 19 are formed by internal or external gaps extending along the transverse sides between each pair of heat exchanger plates 100. It is also to be noted that the heat exchanger plates 100 are connected to each other in such a way that the first plate interspaces 12 are closed along the transverse sides, i.e. towards the recirculation channels 19 of the inner space 2.

(17) The embodiment of the heat exchanger device disclosed in this application may be used for evaporating a two-phase medium supplied in a liquid state via the inlet 5 and discharged in a gaseous state via the outlet 6. The heat necessary for the evaporation is supplied by the plate package 200, which via the inlet conduit 16 is fed with a fluid for instance water that is circulated through the second plate interspaces 13 and discharged via the outlet conduit 17. The medium, which is evaporated, is thus at least partly present in a liquid state in the inner space 2. The liquid level may extend to the level 22 indicated in FIG. 1. Consequently, substantially the whole lower part space 2′ is filled by medium in a liquid state, whereas the upper part space 2″ contains the medium in mainly the gaseous state.

(18) Now turning to FIG. 3, a detailed first embodiment of the heat exchanger plate 100 is disclosed. The heat exchanger plate 100 is intended to form part of the plate package 200 according to the invention. The heat exchanger plate 100 may easily be converted into a heat exchanger plate of a first type A or a heat exchanger plate of a second type B in a manner to be described below.

(19) The heat exchanger plate 100 is provided by a pressed thin walled sheet metal plate. The heat exchanger plate 100 may by way of example be made of stainless steel. The heat exchanger plate 100 has a geometrical main extension plane q and a circumferential edge portion 101. The circumferential edge portion 101 delimits a heat transferring surface 102 extending essentially across the geometrical main extension plane q.

(20) The circumferential edge portion 101 comprises a curved upper portion 103, a substantially straight lower portion 104 and two opposing side portions 105 interconnecting the upper and the lower portions 103, 104. The two opposing side portions 105 do each have a curvature corresponding to the curvature of the inner wall 3 of the shell 1 of the heat exchanger device.

(21) The heat transferring surface 102 comprises a corrugated pattern 106 of ridges and valleys. To facilitate the understanding of the invention the corrugated pattern 106 in and around the first and second portholes 107, 108 (to be discussed below) have been removed. The corrugations 106 extend in different directions at different parts of the heat exchanger plate 100. When a plurality of heat exchanger plates 100 are stacked, one on top of the other, to thereby form the plate package 200, every second heat exchanger plate 100 (heat exchanger plate of the first type A) is turned in the manner disclosed in FIG. 3, whereas every other heat exchanger plate 100 (heat exchanger of the second type B) is rotated 180 degrees about a substantially vertical rotary axes coinciding with the sectional plane p. Thereby the corrugations 106 of adjacent heat exchanger plates 100 will cross each other. Also, a plurality of contact points will be formed where the ridges of the adjacent heat exchanger plates 100 abut each other. A layer of bonding material (not disclosed) may be arranged between the heat exchanger plates 100 during stacking. As the stack later is subjected to heat in an oven, the heat exchanger plates 100 will bond to each other along the contact points and thereby form a complex pattern of fluid channels. In such a way, an efficient heat transfer from the fluid to the medium is ensured at the same time as the plates included in the plate package 200 are given the required mechanical support.

(22) Depending on how the heat exchanger plate 100 is oriented in the plate package 200, one side of the heat exchanger plate 100 will, during operation of the plate package 200 in a heat exchanger device 300, face the first plate interspace 12 and hence be in contact with the two-phase medium, whereas the opposite side of the heat exchanger plate 100 will face the second plate interspace 13 and hence be in contact with the fluid.

(23) The heat exchanger plate comprises a first porthole 107 intended to form an inlet port to the plate package 200 and a second porthole 108 intended to form an outlet port to the plate package 200.

(24) In the disclosed embodiment, the first porthole 107 is located in the proximity of the lower portion 104 and the second porthole 108 is located in the proximity of the upper portion 103. When the heat exchanger plate 100 is arranged to form part of a plate package 200, the fluid will hence during operation, flow upwardly through the second plate interspaces 12 in the plate package 200. Alternatively, it is possible to provide the first portholes 107 at the upper portion 103 and the second portholes 108 at the lower portion 104. It is also possible to provide the portholes 107, 108 in other positions on the heat exchanger plate 100.

(25) Now turning to FIGS. 3 and 4 the heat exchanger plate 100 comprises a draining channel flange 109 that extends along the two opposite side portions 105 of the circumferential edge portion 101. The draining channel flange 109 also has an extension that partly extends along the lower portion 104 of the circumferential edge portion 101.

(26) The draining channel flange 109 extends from the circumferential edge portion 101 in direction from the geometrical main extension plane q. The draining channel flange 109 extends from the circumferential edge portion 101 at an angle β to the normal of the geometrical main extension plane q.

(27) Also, the heat exchanger plate 100 comprises a ridge 110 that extends along the two opposite side portions 105 of the circumferential edge portion 101. The ridge 110 is located at a distance from the draining channel flange 109 and follows the curvature thereof. In the disclosed embodiment, the ridge 110 also has an extension that partly extends along the upper portion 103 of the circumferential edge portion 101.

(28) Now turning specifically to FIG. 4, a cross section of a plate package 200 being arranged in the shell 1 of a heat exchanger device 300 is disclosed. A draining channel 111 is disclosed as seen transverse its longitudinal extension. In the disclosed embodiment, the draining flange 109 of every second heat exchanger plate 100 has been cut-off to thereby convert that plate into a heat exchanger plate 100 of the second type B. In all other aspects the heat exchanger plates are identical.

(29) When two heat exchanger plates 100 of the first and second types A, B are stacked as disclosed in FIG. 4, the ridges 110 of two subsequent heat exchanger plates 100 will form mating abutment portions 112. In a bonded condition, the abutment portions 112 of a heat exchanger plate 100 of the first type A will sealingly abut the corresponding abutment portions 112 of a heat exchanger plate 100 of the second type B.

(30) The mating abutment portions 112 extend along and at a distance from the circumferential edge portion 101, thereby separating the respective first plate interspaces 12 into an inner heat transferring portion HTP and two outer draining portions DP. When stacked, the draining channel flanges 109 of the respective heat exchanger plates 100 are oriented in one and the same direction, and have an extension with a component along a normal to the main extension plane such that a draining channel flange 109 of a first heat exchanger plate 100 of the first type abuts or overlaps a draining channel flange 109 of a subsequent heat exchanger plate. It is to be understood that the subsequent heat exchanger plate 100 may be either a heat exchanger plate 100 of the first type A or a heat exchanger plate 100 of the second type B.

(31) The draining channel flanges 109 form outer walls to the outer draining portions DP thereby transforming the outer draining portions DP into draining channels 111. After bonding, the draining channel flanges 109 of a heat exchanger plate 100 of the first type sealingly abuts or sealingly overlaps the draining channel flanges 109 of a subsequent heat exchanger plate 100 of the first or the second type.

(32) The draining channel 111 has a cross section as seen transverse its longitudinal extension that is defined by the draining channel flange 109, the outer draining portion DP and the abutment portion 112 of a heat exchanger plate 100 of the first type A, and by the abutment portion 112 and the outer draining portion DP of an adjacent heat exchanger plate 100 of the second type B.

(33) The draining channel 111 preferably has, as seen in a cross section transverse its longitudinal extension, a uniform cross-sectional geometry along its longitudinal extension.

(34) When the resulting plate package 200 is arranged in the shell 1 of a heat exchanger device 300, the respective draining channel flanges 109 may be in contact with the inner wall 3 of the shell 1.

(35) In the disclosed embodiment, the ridges 110 are of equal height. The skilled person will understand that the ridges 110 may be of different height and also that one heat exchanger plate 100 may be provided with a ridge 110, whereas the subsequent heat exchanger plate 100 may comprise an essentially flat mating abutment portion 112.

(36) Now turning to FIG. 3 anew, the draining channel 111 has an inlet opening 113 facing the upper portion 103 of the circumferential edge portion 101. The inlet opening 113 has a mouth 114 having a generally horizontal extension. Further, the draining channel 111 has an outlet opening 115 facing the lower portion 104 of the circumferential edge portion 101. The draining channel flange 109 extends past a transition between the side portion 105 and the lower portion 104 of the circumferential edge portion 101.

(37) Now turning to FIG. 4, when a plate package 200 that is composed by heat exchanger plates 100 of this type is used in a heat exchanger device 300 of the plate-and-shell type, medium in liquid form that is present in the upper part space 2″ of the shell 1 may be guided inside and along a plurality of draining channels 111 that extend along opposing side portions of the inner wall surface 3 of the shell 1 but at a distance therefrom, and also at a distance from the first plate interspaces 12 that are formed between opposing major surfaces of the heat exchanger plates 100. The distance is provided, depending on the design of the walls and the joints respectively defining the cross section of the draining channel 111 by at least the material thickness of the sheet material making up the heat exchanger plates 100. The distance formed can be seen as an insulation which reduces heat transfer from the inner wall surface 3 of the shell 1 and from the first plate interspaces 12 in the plate package 200 towards the draining channel 111 and which thereby reduces the risk of the liquid medium evaporating inside the draining channel 111 and thereby disturbance or stopping of the thermo-syphon loop. Thereby a more stable liquid flow is promoted.

(38) Also, the draining channels 111 prevents the compressor oil, which typically, due to its stronger affinity to carbon steel than stainless steel, is prone to follow the curvature of the inner wall surface 3 of the shell 1, from transferring into the first interspaces 12 of the plate package 200. By the presence of the draining channels 111, the compressor oil that is present inside the interspace between the inner wall surface 3 of the shell 1 and the outer boundary of the plate package 200 is prevented from transferring in a direction transverse the longitudinal extension of the draining channel 111 and into the first plate interspaces 12. Instead, the inflow of compressor oil into the first plate interspaces 12 is now restricted to longitudinal gaps 116 facing the upper part space 2″ of the shell 1 and which forms openings towards to the first interspaces 12.

(39) Now turning to FIG. 3 anew, the first porthole 107 is arranged in a lower section of the heat exchanger plate 100 and located at a distance from the lower portion 104 of the circumferential edge portion 101. Thereby a first intermediate portion 117 is defined which is located between the circumferential edge portion 101 and a circumferential edge 118 of the first porthole 107. The first intermediate portion 117 includes the shortest distance d1 between a centre of the first porthole 107 and the lower portion 104 of the circumferential edge portion 101. Also, the first intermediate portion 117 has a height Y1 along the shortest distance d1 and a width X1 transverse to the shortest distance d1.

(40) A first shielding flange 119 is arranged to have an extension along the lower portion 104 of the circumferential edge portion 101. The first shielding flange 119 is arranged to extend along at least a section of the first intermediate portion 117. The first shielding flange 119 extends towards the surface of the heat exchanger plate 100 that is intended to be in contact with the fluid, i.e. the surface that is intended to face the second plate interspace.

(41) The first shielding flange 119 has a length L1 as seen in a direction transverse the shortest distance d1, being smaller than the diameter D1 of the first porthole 107 and more preferred smaller than 80% of the diameter D1 of the first porthole 107.

(42) The second porthole 108 is arranged in an upper section of the heat exchanger plate 100 and located at a distance from the upper portion 103 of the circumferential edge portion 101. Thereby a second intermediate portion 120 is defined which is located between the circumferential edge portion 101 and a circumferential edge 121 of the second porthole 108. The second intermediate portion 120 includes the shortest distance d2 between a centre of the second porthole 108 and the upper portion 103 of the circumferential edge portion 101. Also, the second intermediate portion 120 has a height Y2 along the shortest distance d2 and a width X2 transverse to the shortest distance d2.

(43) A second shielding flange 122 is arranged to have an extension along the upper portion 103 of the circumferential edge portion 101. The second shielding flange 122 is arranged to extend along at least a section of the second intermediate portion 120. The second shielding flange 122 extends towards the surface of the heat exchanger plate 100 that is intended to be in contact with the fluid, i.e. the surface that is intended to face the second plate interspace 13.

(44) The second shielding flange 122 has a length L2 as seen in a direction transverse the shortest distance d2, being 200-80% of the diameter D2 of the second porthole 108 and more preferred 180-120% of the diameter D2 of the second porthole 108.

(45) As is best seen in FIGS. 3 and 6, the curvature of the upper portion 103 of the circumferential edge portion 101 of the heat exchanger plate 100 differs from the curvature of the lower portion 104 of the heat exchanger plate 100. When the heat exchanger 100 is included in a plate package 200 and used in a heat exchanger device 300, the lower portion 104 is intended to face the collection space 18 that is formed in the shell 1 beneath the plate package 200. To allow the collection space 18 to have a certain volume, the lower portion 104 is in the disclosed embodiment more or less straight, whereas the upper portion 103 which is intended to face the upper part space 2″ of the shell 1 has a convex curvature. Accordingly, the extension of the circumferential edge portion 101 adjacent a porthole 107; 108 affects the area of the available intermediate portion 117; 120.

(46) In the case where the lower portion 104 is essentially straight, the height Y1 of the first intermediate portion 117 between the lower portion 104 and the circumferential edge 118 of the first porthole 107 will increase rather rapidly with the distance X1 from the sectional plane p. This can be compared to the second porthole 108 adjacent the curved upper portion 103 where the height Y2 of the second intermediate portion 120 between the curved upper portion 103 and the circumferential edge 121 of the second porthole 108 will increase more slowly with the distance X2 from the sectional plane p. The decisive factor in this case is the radius of the curved upper portion 103.

(47) The impact from this difference can be seen by studying the temperature gradient when subjecting a stack of heat exchanger plates 100 to heat in an oven. The second intermediate portion 120 with the curved upper portion 103 will heat more rapidly than the first intermediate portion 117 with the straight lower portion 104. By introducing the first and the second shielding flanges 119; 122 and adjusting their lengths L1; L2 to the diameter D1; D2 of the respective porthole 107; 108, the difference in heating may be compensated for. Thereby the risk of buckling due to uneven thermal expansion and thereby insufficient bonding may be dealt with.

(48) Now turning to FIG. 5 a schematic cross section of a plate package 200 which is composed of a plurality of heat exchanger plates 100 of the above type is disclosed. The cross section in FIG. 5 is taken transverse the first shielding flange 119. For the record, a corresponding cross section taken transverse the second shielding flange 122 may look the same.

(49) As given above, the heat exchanger plate 100 according to the invention can easily be converted into either a heat exchanger plate 100 of a first type A or into a heat exchanger plate 100 of a second type B by simply cutting off the first and second shielding flanges 119; 122 and the draining channel flanges 109 after pressing.

(50) When stacking the heat exchanger plates 100 to a form a plate package 200, one on top of the other, every second heat exchanger plate 100 is turned in the manner disclosed in FIG. 4, whereas every other plate is rotated 180 degrees about a substantially vertical rotary axes coinciding with the sectional plane p. Thereby the corrugated patterns 106 of adjacent heat exchanger plates 100 will cross each other. Also, a plurality of contact points will be formed where the ridges 110 of the adjacent heat exchanger plates 100 abut each other. Like in prior art, a layer of bonding material (not disclosed) may be arranged between the heat exchanger plates 100 during stacking. As the stack later is subjected to heat in an oven, the heat exchanger plates 100 will bond to each other along the contact points and thereby form a complex pattern of fluid channels. It is to be understood that the width of the joints depends of the cross section of the corrugated pattern 106.

(51) Depending on how the heat exchanger plate 100 is oriented in the plate package 200, one side of the heat exchanger plate 100 is intended to during operation of the plate package 200 face the first plate interspace 12 intended to be in contact with the medium, whereas the other side of the heat exchanger plate 100 will face the second plate interspace 13 intended to be in contact with the fluid, such as water.

(52) As is seen in the embodiments of FIGS. 4 and 5, the flanges 109; 119 of every second heat exchanger plate 100, i.e. the heat exchanger plate 100 of the second type B have been cut off. Also, the flanges 109; 119 of the respective heat exchanger plates 100 of the first type A are oriented in one and the same direction, and have an extension with a component along a normal to the main extension plane q such that a flange 109; 119 of a heat exchanger plate 100 of the first type A abuts or overlaps a flange 109; 119 of a second subsequent heat exchanger plate 100 of the first type A. The thus formed overlap between two subsequent flanges has a length e as seen in a direction corresponding to the normal of the geometrical main extension plane corresponding to 5-90% of the height f of the flange 109; 119.

(53) It is to be understood that it may be sufficient if the flange 109; 119 of a heat exchanger plate 100 of the first type A abuts a flange 109; 119 of a subsequent heat exchanger plate 100.

(54) The flanges 109; 119 are disclosed as extending from the circumferential edge portion 101 at an angle α, β to the normal of the geometrical main extension plane q. The angles α, β are preferably smaller than 20 degrees to the normal, and more preferred smaller than 15 degrees to the normal. It is to be understood that the angles α, β can be as small as 0 degrees. The angles α, β may be the same or be different from each other.

(55) The angles α, β depend on if both of two subsequent heat exchanger plates 100 to be joined are provided with flanges 109; 119 or if only one of the heat exchanger plates 100 have a flange 109; 119. In case of only one of the heat exchanger plates 100 having a flange 109; 119, the angles α, β can be made smaller, such as smaller than 10 degrees, such as smaller than 8 degrees, and typically about 6-7 degrees.

(56) The bonding of the heat exchanger plates 100 to provide the plate package 200 may be made by brazing or by fusion bonding as discussed above. Fusion bonding is especially suitable when the heat exchanger plates are made by stainless steel.

(57) Now turning to FIG. 6 one embodiment of the plate package 200 according to the invention is schematically disclosed as being contained in a heat exchanger device 300 according to the invention. From this view it can clearly be seen how the first and second shielding flanges 109; 122 and also the two opposing draining channel flanges 109 form sealed circumferential side walls of the plate package 200. By the limited length of the first and second shielding flanges 119; 122, the communication between the interior of the shell 1 and the first plate interspace 12 is not restricted to any substantial degree.

(58) It is contemplated that there are numerous modifications of the embodiments described herein, which are still within the scope of the invention as defined by the appended claims.

(59) By way of example, the heat exchanger plates of the first and second types may be identical with the only exception that the first and second flanges and the draining channel flanges 109 on every second heat exchanger plate 100 are cut-off to thereby convert them into heat exchanger plates of the first and the second type. Thereby, one and the same press tool may be used.

(60) It is to be understood that also the heat exchanger plates of the second type may be provided with flanges of the type described above and that these flanges are not cut-off. This allows for the flanges of heat exchanger plates of the first type to sealingly abut flanges of heat exchanger plates of the second type.

(61) The plate package has been disclosed as being applied to a heat exchanger of the plate-and shell type. The skilled person will understand that the concept also is applicable to other types of heat exchangers.