PAIR OF PLATES FOR A PLATE HEAT EXCHANGER

Description

DOMAINE DE L'INVENTION

[0001] The invention relates to the field of plate heat exchangers used in particular for the exchange of heat between two gases, but also between two liquids or between a liquid and a gas.

[0002] Heat exchangers of particular interest for the invention are gas-gas exchangers which operate with large or small flow volumes at relatively low pressures, for example from 0.1 to 1.5 MPa. They can be used for example as air preheaters for furnaces or can be part of NOx reduction plants ("DeNOx" devices).

[0003] Heat exchangers are designed to transfer heat between a high-temperature fluid and a low-temperature fluid without mixing them. Plate heat exchangers offer good thermal performance thanks to their large heat exchange surface area, while being compact.

[0004] Plate heat exchangers recover heat by arranging a plurality of plates stacked parallel to each other at predetermined intervals. The plates are spaced such that the space between two adjacent plates forms a channel through which a fluid can flow. A high-temperature fluid and a low-temperature fluid are alternately supplied to successive channels so as to effect heat transfer between the high-temperature fluid and the low-temperature fluid through each plate. ÉTAT DE LA TECHNIQUE:

[0005] Patent EP165179B1 describes a plate heat exchanger characterized in that the channels are defined by the space included between pressed quadrilateral plates. Said pressed plates comprise two pairs of opposite edges bent at 90° in opposite directions: one pair upwards and one pair downwards if the plates are considered in a horizontal plane. The pressed plates are mounted symmetrically and are associated with each other by welding their vertical edges. In such a heat exchanger, the inlet and outlet of each channel are identical. Each pressed plate requires at least four bending operations for its manufacture.

[0006] Patent application US2010 / 0006274A1 describes a plate heat exchanger consisting of quadrilateral plates having at least two opposite edges curved relative to the heat transfer surface. The fluid channels are defined by the space between a pair of identical plates which are positioned as a mirror image of each other. Therefore, the two curved edges of one plate are in contact with the two curved edges of the symmetrical plate. Thus, the plates are curved on at least two opposite edges. Document FR 2 969 269 A1 describes a pair of heat exchanger plates according to the preamble of claim 1.

[0007] The object of the invention is to provide an improved plate heat exchanger, in particular with a plate design ensuring a reduced number of manufacturing operations and / or a reduced manufacturing time, and preferably without affecting the heat transfer performance and the corrosion resistance, in particular the resistance to cracking corrosion. RÉSUMÉ DE L'INVENTION :

[0008] The pair of heat exchanger plates according to the invention, comprising a central panel with at least four sides, said central panel preferably being quadrilateral or quadrilateral with truncated corners, can be defined as follows: a first side of the central panel is inclined relative to said central panel and forms a first junction panel; the opposite side of said first side is flat.

[0009] It is specified that a "plane" side within the meaning of the invention is to be understood with its usual meaning, namely that the side is entirely planar, from one end to the other of the edge in question, and it therefore does not include any portion which is not, and which, for example, would be inclined.

[0010] Compared to previously known heat exchanger plates, the plate according to the invention is produced with a reduced number of operations, since only one bending operation is required to manufacture the plate. The heat exchanger plate has a heat transfer performance similar to that of conventional heat exchanger plates.

[0011] Compared to the already known heat exchanger plates, a single joining panel on two successive heat exchanger plates is possibly sufficient to mechanically connect them.

[0012] Compared to previously known heat exchanger plates, the corrosion resistance of the heat exchanger plate according to the invention is improved. The plate according to the invention makes it possible to maintain the temperature of the plate wall above the dew point of the fluid, while a hot gas flows at the inlet and outlet of the heat exchanger channel, which reduces the risk of corrosion due to condensed acids. In addition, the design of the channel inlet and outlet has a geometry with a lower risk of cracking corrosion since the number of bent edges is reduced.

[0013] Compared to previously known heat exchanger plates, the plate according to the invention can be welded in such a way that it is not necessary to compensate for the expansion of the corners of the plate and it is not necessary to use a dedicated expansion device in the casing of the heat exchanger.

[0014] Advantageously, the first junction panel of the heat exchanger plate according to the invention comprises a first part, in particular a single part, said first part forming an angle α with said central panel. In this way, the plate is very easy to manufacture.

[0015] According to the invention, the first joining panel of the heat exchanger plate according to the invention is manufactured from a first part and a second part extending from said first part, said first part forming an angle α with the central panel and said second part being parallel to the central panel. The first joining panel can be manufactured with both parts in a single bending operation. The second part can advantageously be used to weld the first joining panel to another heat exchanger plate. Thus, the plate with a single joining panel can be manufactured in a single bending operation. As a result, the plate is very easy to manufacture and can be very easily assembled to another plate.

[0016] In the latter two cases, the angle α between the first part of the first junction panel and the central panel is preferably between 10° and 90°, preferably between 20° and 60°, and more preferably between 30° and 50°.

[0017] According to a first embodiment of the invention, a second side of the central panel of the heat exchanger plate according to the invention may be inclined relative to the central panel, said second side being adjacent to the first side and said second side forming a second joining panel inclined in the opposite direction relative to the first joining panel. Furthermore, the opposite side of said second side may be either flat or inclined so as to form a third joining panel, said third joining panel being a mirror image of said second joining panel.

[0018] In this first embodiment, the second joining panel can be used to mechanically connect the central panel of said heat exchanger plate to another heat exchanger plate.

[0019] In this first embodiment, either the opposite side of said second side is flat and the two joining panels of the heat exchanger plate according to this embodiment can be mechanically connected to two heat exchanger plates having two joining panels, each of the joining panels being connected to one of the two plates. Or, alternatively, the opposite side of said second side is inclined so as to form a third joining panel which is a image en miroir said second joining panel, i.e. the edge opposite the second joining panel is inclined in the same direction as the second joining panel. The heat exchanger plate with three joining panels can be mechanically connected to two other heat exchanger plates having only a first joining panel, the first joining panel being connected to one plate and the second and third joining panels being connected to the other plate.

[0020] Advantageously, in this first embodiment of the invention, the second joining panel of the heat exchanger plate according to the invention comprises a first part, in particular a single part, said first part forming an angle β with the central panel. In this way, the plate is very easy to manufacture.

[0021] Advantageously, in this first embodiment of the invention, the second joining panel of the heat exchanger plate according to the invention is manufactured from a first part and a second part extending from said first part, said first part forming an angle β with the central panel and said second part being parallel to the central panel. The second joining panel can be manufactured with both parts in a single bending operation, so that the plate with two joining panels can be manufactured in two bending operations. The second part of the joining panel can be used to weld the second joining panel to another heat exchanger plate. As a result, the plate is very easy to manufacture and very easy to assemble with two other plates having two joining panels.The third joining panel, if any, is a mirror image of the second joining panel and requires a third bending operation. However, the plate with three joining panels can be joined with two plates having only a first joining panel so that overall, the manufacture of a pair of plates requires only four bending operations.

[0022] Advantageously, in the last two cases of the first embodiment, said angle β between the first part of the second junction panel and the central panel is between 10° and 120°, preferably between 20° and 110°, and more preferably between 30° and 100° or, in particular, is 45° or 90°.

[0023] Another object of the present invention is a pair of heat exchanger plates comprising two spaced heat exchanger plates, as described above, i.e., a first and a second heat exchanger plate, the central panels of which are parallel to each other, wherein the first junction panel of the first heat exchanger plate and the first junction panel of the second heat exchanger plate are arranged so as to face each other, opposite each other, the first junction panel of said first heat exchanger plate is fixed directly to the central panel of the second heat exchanger plate on said opposite plane side, the first junction panel of said second heat exchanger plate is fixed directly to the central panel of the first heat exchanger plate on said opposite plane side, the space between the first and second heat exchanger plates forms a first channel for receiving a first fluid.

[0024] The two plates of the pair of plates according to the invention are assembled by their first joining panels. The space between the two plates forms the first channel for receiving a first fluid. The first channel has a trapezoidal section which remains identical over its entire length. The speed of the fluid is substantially constant over the entire length of the channel, which can be advantageous depending on the nature of the fluids.

[0025] As the manufacturing time of each heat exchanger plate is reduced compared to that of conventional heat exchanger plates, the manufacturing time of the plate pair is also reduced.

[0026] Another object of the present invention is a stack of pairs of heat exchanger plates, comprising two successive pairs of spaced plates as described above, a first pair of heat exchanger plates and a second pair of heat exchanger plates, wherein: said first pair and said second pair are arranged parallel to each other, the space between the first and second pair of heat exchanger plates forms a second channel for receiving a second fluid, preferably, said second pair is identical to said first pair, or said second pair is a mirror image of said first pair.

[0027] Stacking two pairs of successive plates spaced apart according to the invention makes it possible to form the second channel for receiving a second fluid. The second channel has a cross-section that varies along the length of the second channel. The velocity of the fluid varies along the length of the channel, which can be advantageous depending on the nature of the fluids. The manufacturing time of each pair of heat exchanger plates is reduced compared to that of conventional pairs of heat exchanger plates, so that the manufacturing time of the stack of pairs of plates is also reduced.

[0028] Advantageously, the two successive pairs of the stack of pairs of plates according to the invention are connected laterally by closing means, said closing means preferably comprising a lateral bar, a cover plate with a C or U profile, or a flat cover plate of hexagonal or pentagonal shape.

[0029] According to a first embodiment of the invention, referred to as the "single junction panel" mode throughout this text, the heat exchanger plates according to the invention do not have a second junction panel.

[0030] According to another embodiment of the invention, referred to as the "two junction panel" mode throughout the present text, the stack of pairs of heat exchanger plates as described above, said second pair being preferably identical to said first pair, comprises heat exchanger plates such that a second side of the central panel is inclined relative to the central panel, said second side being adjacent to the first side and said second side forming a second junction panel being inclined in the opposite direction relative to the first junction panel, and the opposite side of said second side is planar. The stack according to the invention is then such that: advantageously, the second joining panel of the second heat exchanger plate of the first pair is fixed directly to the central panel of the first heat exchanger plate of the second pair and the second joining panel of the first heat exchanger plate of the second pair is fixed directly to the central panel of the second heat exchanger plate of the first pair, optionally, either closing means can laterally connect said two pairs, on the side of the second joining panels, or the corner area at the intersection between the first and second joining panels can be shaped so as to mechanically connect said two pairs.

[0031] Stacking two pairs of successive spaced plates according to this embodiment of the invention allows the first and second joining panels to be used to mechanically connect the heat exchanger plates. The manufacturing time of each pair of heat exchanger plates is reduced compared to that of conventional pairs of heat exchanger plates, and the manufacturing time of the stack of plate pairs is also reduced.

[0032] Where the corner area at the intersection of the first and second junction panels is formed to mechanically connect the two pairs of plates, it may not be necessary to use cover plates.

[0033] In the "two joining panel" mode, the stack of pairs of heat exchanger plates may advantageously comprise heat exchanger plates in which said second joining panel of each plate of the stack comprises a first portion, in particular a single portion, said first portion forming an angle β with the central panel, or in which said second joining panel of each plate of the stack is manufactured from a first portion and a second portion extending from said first portion, said first portion forming an angle β with the central panel and said second portion being parallel to the central panel.

[0034] Another object of the invention is a plate heat exchanger comprising the heat exchanger plates and / or pairs of heat exchanger plates and / or a stack of pairs of heat exchanger plates as described above, arranged in a suitable casing.

[0035] The present invention also relates to a method of manufacturing a pair of heat exchanger plates as described above, said method comprising the following steps: preparing two central panels, preferably quadrilateral, possibly truncated, comprising a first side and a second side adjacent to the first, for each of said central panels, folding said first side so as to form a first joining panel, said first joining panel comprising a first part, in particular a single part, said first part forming an angle α with the central panel, optionally, for each of said central panels, folding said second side so as to form a second joining panel, said second joining panel comprising a first part, in particular a single part, said first part forming an angle β with the central panel, arranging the two heat exchanger plates so that their first joining panels are opposite each other and their central panels are parallel to each other,joining the two heat exchanger plates so as to form a pair of plates, the space between the two plates forming a first fluid channel, mechanically fixing the two plates along their first joining panels.

[0036] The assembly of the heat exchanger plate pair is easy and involves a reduced number of bending operations, which reduces manufacturing costs and time.

[0037] The present invention also relates to a method of manufacturing a stack of pairs of heat exchanger plates as described above, said method comprising: preparing at least four central panels, preferably quadrilateral, possibly truncated, comprising a first side and a second side adjacent to the first, for each of said central panels, folding said first side so as to form a first joining panel, said first joining panel comprising a first part, in particular a single part, said first part forming an angle with the central panel, optionally, for each of said central panels, folding said second side so as to form a second joining panel, said second joining panel comprising a first part, in particular a single part, said first part forming an angle β with the central panel, arranging the heat exchanger plates in pairs so that their first joining panels are opposite each other, facing each other, and their central panels are parallel to each other,joining the heat exchanger plates so as to form at least two pairs of plates, the space between the two plates forming a first fluid channel, mechanically fixing the two plates of each pair along their first joining panels, stacking the at least two pairs of plates, the space between the pairs of heat exchanger plates forming a second fluid channel, Optionally, mechanically fixing the two pairs of plates along their second joining panels.

[0038] In the "single junction panel" embodiment of the invention, the plates of the heat exchanger may be substantially identical, and are preferably identical, which makes assembly easier and reduces manufacturing costs: to form a stack of pairs, it is sufficient, for example, only to prepare a first stack of plates, and a second stack of plates in which the plates, in particular all identical, have undergone a 180° rotation and have been turned over. Then, the plates are taken alternately from the two stacks to gradually manufacture the stack. The process can be automated.

[0039] In the "two joining panel" embodiment of the invention, the heat exchanger plates may be substantially similar: the second joining panel is located alternately on one side and the other of the first joining panel, for two plates that follow one another in the stack of plates. Indeed, the second joining panels may thus be opposite each other when two successive pairs are assembled. This makes assembly easy and reduces manufacturing costs: to form a stack of pairs, it is sufficient, for example, only to prepare a first stack of plates of the first type and a second stack of plates to manufacture the stack. The process may be automated. DESCRIPTION

[0040] Throughout this text, the terms "supply" or "inlet" and "outlet" or "discharge" and "in" or "out of" are used with reference to the direction of flow of fluids.

[0041] Throughout this text, the term "side" of the central panel is used with reference to the periphery of the central panel, over a certain width, for example up to 5% of the width of the plate.

[0042] Throughout this text, the term "mirror image" means symmetry about a plane in the middle of the space separating the object from its image.

[0043] The invention can be used, for example, for plate heat exchangers operating according to the cross-flow principle in which the fluids flowing over both sides of each plate are directed substantially perpendicular to each other. The invention can also be used for plate heat exchangers operating according to a counter-flow principle, in which the fluids flowing over both sides of each plate are directed substantially in opposite directions. The invention can also be used for plate heat exchangers operating according to a co-current flow principle in which the fluids flowing over both sides of each plate are directed substantially in the same direction. The invention can also be used for plate-type heat exchangers operating according to other flow principles.

[0044] The invention is particularly suitable for the exchange between two fluids, in particular two gases, but can also be used to exchange heat between two liquids or between a liquid and a gas.

[0045] The invention is more particularly suitable for the exchange between two gases, in particular gas flows at the inlet and outlet of a single piece of equipment, such as for example the air to be conveyed to a furnace and the fumes from the same furnace or similarly, the hot stream coming from a NOx reduction system and the cold stream going to the same NOx reduction system.

[0046] A plate heat exchanger according to the invention can be used for fluids operating at a pressure ranging from full vacuum pressure up to 1.5 MPa, preferably from 0.1 to 1.0 MPa, more preferably from 0.1 to 0.6 MPa.

[0047] A plate heat exchanger according to the invention may consist either of channels of uniform height or of channels of different heights on each circuit. Correspondingly, the height of the first junction panel and the heights of the second and third junction panels, if any, may be similar or different.

[0048] The channel height (the spacing between two consecutive plates) can be determined according to the service conditions. Typically, it can be 5 to 30 mm, including 5 mm, 10 mm, 15 mm, 20 mm, 30 mm or any suitable height.

[0049] The width of the heat exchanger plate according to the invention may typically be between 1000 mm and 2000 mm, preferably between 1300 mm and 1700 mm. The length of the heat exchanger plate according to the invention may typically be between 1000 mm and 7500 mm, preferably between 1500 mm and 7000 mm. The thickness of the plate may be between 0.6 mm and 6 mm, preferably between 1.5 mm and 2.0 mm.

[0050] The central panel of the heat exchanger plate according to the invention may have any suitable shape, for example trapezoidal, hexagonal or quadrilateral. The central panel is most preferably quadrilateral, in particular rectangular or square, possibly with truncated corners.

[0051] The central panel comprises a first face (or lower face) and a second face (or upper face) opposite the first face. The first and second faces may be flat but may also locally include reliefs, grooves or protrusions.

[0052] Advantageously, dimples may be added or pressed into the central panel of the plates. Dimples may be implemented on one face of the plate or on both faces of the plate with several arrangements depending on the characteristics of the plate and the use of said dimples. The dimples may be used as spacers and are intended to minimize deformation of the plates when stacked on top of each other. Single or double dimples are typically distributed over the surface of the central panel of the heat exchanger plates.

[0053] Optionally, pin fins or pin fins may also be welded onto the central panel of the heat exchanger plate according to the invention using resistance welding.

[0054] According to a preferred embodiment of the invention, the heat exchanger according to the invention is such that: the first channel is located between the two heat exchanger plates of a single pair of plates according to the invention. Said two plates are mechanically connected by their first joining panels on each side. The first channel has a trapezoidal cross-section and said section maintains the same dimension over the entire length of the channel. The fluid enters directly at a given speed into the channel. Then, the speed of the fluid flow is constant over the entire length of the channel. The fluid also exits at the same speed. Therefore, the first channel is said to have "direct" inlet and outlet zones ("bluff" in Anglo-Saxon terminology), unlike the second channel. on the contrary, the second channel is located between two successive spaced pairs of two plates. The section of the channel is not constant over the entire length of the channel.Indeed, a cross-section of the second channel shows that the inlet and outlet areas are larger than the rectangular central section of the channel. Therefore, the fluid velocity varies along the length of the second channel: it increases as the channel section decreases in the first part of the channel (the inlet) and it decreases as the channel section increases in the last part of the channel (the outlet). Therefore, the second channel is said to have a "sharp" inlet and outlet area, unlike the first channel.

[0055] In the remainder of this text, the first channel with a "direct" input and output is called the "direct channel" and the second channel with the "live" input and output is called the "live channel".

[0056] According to a first mode of operation of the invention, the hot fluid to be treated in the plate heat exchanger on the hot side can be sent to the "direct channels" and the cold fluid to be treated on the cold side can be sent to the "live channels".

[0057] According to a second mode of operation of the invention, the cold fluid to be treated in the plate heat exchanger on the cold side can be sent to the "direct channels" and the hot fluid to be treated on the hot side can be sent to the "live channels".

[0058] When the hot fluid flows in the "direct channel", the profile of the heat exchanger plate is favorable to the condensation of the hot fluid vapor. On the contrary, when the hot fluid flows in the "live channel", the profile of the heat exchanger plate is favorable to prevent the condensation of the hot fluid.

[0059] Advantageously, closing means may be used where appropriate to close the lateral sides of the second channel and ensure the sealing of the channel. Advantageously, said closing means may be mechanically connected to the plates by any means known to those skilled in the art, for example by welding, in particular by seam welding or by bolting.

[0060] In a stack of pairs of plates according to the "single junction panel" mode, in which the heat exchanger plates do not have a second junction panel, the second channel is advantageously provided with means for closing its lateral side between two successive pairs of plates. Said closing means may be lateral bars ("edge bars" in English terminology) or dedicated cover plates ("cover parts" in English terminology) or any equivalent means. The cover plates may be manufactured in one or more pieces, some having a C shape, or a U shape or any profile allowing the second plate of the first pair and the first plate of the second pair to be assembled. The shape of the cover plate may also be octagonal so as to fit in one piece with the cross-section of the second channel.Closing means may be arranged longitudinally along the flow direction of the second fluid at the inlet and outlet of the second channel.

[0061] In a stack of pairs of plates according to the "two joining panel mode", in which heat exchanger plates have two joining panels, successive pairs are joined by the second joining panel of the second plate of the first pair on one side and by the second joining panel of the first plate of the second pair on the other side.

[0062] In this case, either, closing means may advantageously be arranged longitudinally along the direction of flow of the second fluid at the inlet and at the outlet of the second channel. Said closing means may preferably be a polygonal cover plate having a quadrilateral or pentagonal shape.

[0063] Alternatively, the corner area at the intersection between the first and second joining panels may be advantageously pressed or formed such that said corner area is used to mechanically connect the second plate of the first pair and the first plate of the second pair, so that it is not necessary to use closing means. Typically, said corner area may be stamped, embossed, pressed, hammered and enlarged sufficiently to be welded to adjacent plate panels.

[0064] The first and second channels, in particular the second channel, may either be completely empty (free channel), or may comprise any type of reinforcing element such as connecting bars.

[0065] Advantageously, spacers made for example from strips, profiles, protrusions or pin fins may be inserted into the channel to ensure spacing between the plates. They may be loose or may be spot welded or may be held in place using U-shaped profile clamps at the supply and discharge sides.

[0066] Advantageously, the first and second junction panels, comprising a part, in particular a single part, or manufactured from two parts, consist of flat or substantially flat plates.

[0067] According to a preferred embodiment of the invention, the first joining panel or the second joining panel may be mechanically attached to the central panel of the adjacent plate by any possible technique, typically by welding.

[0068] Advantageously, the second part of the first and / or second junction panel may be large enough to allow mechanical attachment of the second part to the central panel of the adjacent plate by any means known to those skilled in the art.

[0069] According to a first variant, the second junction panel can be oriented downwards relative to the plane of the central panel, with an angle β of between 10° and 90°, preferably between 20° and 60°, and more preferably between 30° and 50°.

[0070] According to a second variant, the second junction panel may be oriented downwards relative to the plane of the central panel, with an angle β of between 60° and 120°, preferably between 70° and 110°, and more preferably between 80° and 100°.

[0071] Alternatively, the second portion of the second junction panel may extend from the first portion of the second junction panel parallel to the plane of the central panel, said second portion being either oriented towards the inside of the channel or towards the outside of the channel.

[0072] Each of the first, second or third junction panels may preferably be formed in a single step by deformation. The deformation may be achieved by press forming and / or bending.

[0073] In another embodiment of the invention, different areas of the central heat exchanger panel may be provided with an insulation layer, consisting of a metal plate portion parallel to the central panel with air between the metal plate portion and the central panel. Said insulation layer may allow the temperature of the wall of the heat exchanger plate to be locally modified. Said insulation layer may typically be implemented in the coldest areas of the cold channel and is described for example in patent CZ298773B6.

[0074] According to another embodiment of the pair of two heat exchanger plates according to the invention, a ferrule can be mounted over the edges of the two adjacent plates welded together, acting as a shield protecting the junction. The ferrule is typically made from a piece of sheet metal bent so as to be able to cover the weld joint. The ferrule can be welded to each of the two plates.

[0075] The heat exchanger plate according to the invention may be formed in one piece, usually by one-step deformation of a flat metal sheet made of a weldable material, for example a steel plate or a stainless steel plate. The first and optionally the second and third joining panels may be part of the central panel or may also be attached thereto. In the "two joining panels" mode, a second step of deformation of the flat metal sheet may be required to form the second side joining panel. The deformations may be obtained by press forming and / or bending. The heat exchanger plate according to the invention may also be manufactured by assembling several independent plate pieces. DESCRIPTION DÉTAILLÉE

[0076] Other characteristics and advantages will appear on reading the following description provided for purely illustrative and non-limiting purposes, which must be read with reference to the appended figures, in which: There figure 1a represents two identical heat exchanger plates A and B in the “single junction panel” mode, in which the heat exchanger plates do not have a second junction panel and the figure 1b represents the corresponding pair of plates according to the invention when said plates A and B are assembled. The figures 2a et 2b represent two plates A and B according to the “two junction panel” mode, in which said plates have a first and a second junction panel, according to two different embodiments. The figure 3a represents a stack of two pairs of heat exchanger plates according to a first embodiment and in the figure 3b , according to a second embodiment of the invention. The figures 4a et 4b represent an exploded view of a stack of pairs of heat exchanger plates similar to those of the figures 3a et 3b , but also illustrating cover plates and spacer bars. The figure 5 represents a stack of two pairs of heat exchanger plates according to one embodiment of the invention, in the “two junction panels” mode.

[0077] For the sake of clarity, the figures do not necessarily represent the plates in the spatial position in which they can be assembled or used.

[0078] The reference symbols shown in the figures are indicated below in relation to the components to which they refer: A-Heat exchanger plate AB - Heat exchanger plate BA 0, - Center panel of plate AB 0 - Center panel of plate BA 1 , A 2 , A 3 , A 4 - sides of center panel A 0 B 1 , B 2 , B 3 ,B 4 - sides of the central panel B 0 JA - first junction panel of the central panel A 0 JB - first junction panel of the central panel B 0 A 5 - first part of the first junction panel JAA 6 - second part of the first junction panel JAB 5 - first part of the first junction panel JB of the central panel B 0 B 6 - second part of the first junction panel JBKA - second junction panel of the central panel A 0 KB - second junction panel of the central panel B 0 A 7 - first part of the second junction panel KAA 8 - second part of the second junction panel KAB 7 - first part of the second junction panel KBB 8 - second part of the second junction panel KBA 9 - corner area at the intersection between the first and second junction panels JA and KAB 9 - corner area at the intersection between the first and second junction panels JB and KB . , The references of the components represented remain the same from one figure to another.

[0079] There figure 1a represents two identical heat exchanger plates A and B in the "single junction panel" mode, in which the heat exchanger plates do not have a second junction panel. The central panel A 0 is rectangular and has 4 sides numbered, in a clockwise direction, A 1 , A 2 , A 3 and A 4 . For brevity, all parts of plate B are numbered the same way.

[0080] A first side A 1 of the central panel is inclined relative to the central panel and forms a first junction panel JA. The side A 3 of the central panel located opposite the first junction panel JA is a flat edge. In the embodiment illustrated in the figure 1a , the first joining panel JA is formed of two parts, a first part A 5 forming an angle α with the central panel and a second part A 6 , which is parallel to the central panel plate. The first joining panel JA is connected by the fold line to the central panel, but it could also have been provided as a second piece and have been fixed to the central panel. The first joining panel in two parts is preferably formed in a single pass, by deformation. The first joining panel JA is oriented downwards at an angle of approximately 45° relative to the plane of the central panel A 0 .

[0081] Heat exchanger plate B is identical to A and is positioned symmetrically with respect to A with respect to the point in the center of the gap between plate A and plate B. This means that plate B was arranged after being turned over and rotated 180°, with the first joining panels of plates A and B facing each other.

[0082] There figure 1b illustrates a schematic perspective view of the manner in which the two plates A and B of the figure 1a are assembled and mechanically connected to form a pair of heat exchanger plates according to one embodiment of the invention.

[0083] The two plates of the figure 1a have been superimposed so as to be mechanically connectable. The "bottom face" of plate A faces the "bottom face" of plate B. The first joining panel JA of plate A faces the first joining panel JB of plate B. The second part A 6 of the first joining panel JA of plate A is welded to the plane side B 3 of the central panel of heat exchanger plate B. Similarly, the second part B 6 of the first joining panel JB of plate B is welded to the plane side A 3 of the central panel of heat exchanger plate A.

[0084] The channel formed between plate A and plate B constitutes a first channel of the heat exchanger made up of the plates according to the invention, in which a first fluid F 1 can flow. The first channel has a trapezoidal flow cross-section and said cross-section is the same over the entire length of the channel.

[0085] THE figures 2a et 2b represent a perspective view of two plates A and B according to the “two junction panel” mode, in which the heat exchanger plates have a second junction panel, according to two different embodiments.

[0086] There figure 2a represents two heat exchanger plates A and B in a first embodiment of the “two junction panel” mode. Plates A and B are substantially identical with a second side of their central panel A 0 or B 0 , respectively, which is inclined relative to the central panel, on an adjacent side A 2 or B 2 , respectively to the first junction panel, and which forms a second junction panel KA and KB , respectively. It will be noted, however, that the second junction panels KA and KB of plates A and B are located on opposite adjacent sides, relative to the respective first junction panels JA and JB . Thus plate B is a symmetrical image of plate A following a central symmetry relative to the point located at the center of the space delimited by plates A and B, which makes it easy to associate them in pairs.The second junction panels KA and KB are made of a single part A 7 or B 7 which forms an angle of 90° with the central panel (perpendicular to the plane of the central panel). The second junction panels are preferably formed in a single pass, by deformation. The deformation can be achieved by press forming and / or bending. Furthermore, the heat exchanger plates A and B are equipped with protrusions 1, which can be positioned differently on plate A and plate B.

[0087] There figure 2b represents two heat exchanger plates A and B in a second embodiment of the “two junction panel” mode. Plates B and A are mainly similar to plates A and B of the figure 2a but the second joining panels KA and KB are made from two parts, the first part A 7 and B 7 , respectively and the second part A 8 and B 8 , respectively. The first part A 7 or B 7 is connected by a fold line to the central panel on the edge A 2 or B 2 , respectively and forms an angle of about 45° with the central panel. The second part A 8 or B 8 is parallel to the plane of the central panel. Another difference with the figure 2a is that the corner areas A 9 and B 9 at the intersection between the first and second joining panels JA and KA , JB and KB , respectively, have not been cut out. On the contrary, said corner areas A 9 and B 9 have been formed in such a way that it is not necessary to use cover plates when the two plates are assembled in pairs.

[0088] THE figures 3a et 3b represent a stack of two pairs of heat exchanger plates according to a first embodiment and a second embodiment of the invention.

[0089] There figure 3a depicts a first embodiment of a stack of two spaced pairs of heat exchanger plates, each pair being similar to the pair of plates A and B shown in the figure 1b . In this embodiment, two identical pairs of two plates have been superimposed. The channel formed between the first and second pair constitutes the second channel of the heat exchanger, which is capable of receiving a second flow of fluid F 2 . The section of the second channel is not constant along the length of the channel. Indeed, the second fluid F 2 first enters a rectangular volume, then a trapezoidal volume, then again a rectangular volume. At the outlet of the channel, the situation is reversed: the second fluid enters a trapezoidal volume then a rectangular volume.

[0090] There figure 3b depicts another embodiment of stacking two spaced pairs of heat exchanger plates, each pair being similar to the pair of plates shown in figure 1b , but one of the two pairs having been turned over in order to obtain a second pair which is a mirror image of the first pair. The channel formed between the first and second pairs constitutes the second channel of the heat exchanger, which is capable of receiving a second flow of fluid. The section of the channel is not constant and is different from the section of the channel formed in the figure 3a The heat exchanger plates are equipped with protrusions 1, but alternatively, strips or U-profiles could also be used, for example.

[0091] THE figures 4a et 4b represent an exploded view of assemblies similar to those of the figures 3a et 3b , illustrating cover plates and spacer bars. All heat exchange plates are equipped with double protrusions 2.

[0092] There figure 4a illustrates the two cover plates C which are used to mechanically connect the two successive pairs of plates, arranged in a similar manner to the pairs shown in figure 3a . Cover plates C are octagons having the shape of the cross-section of the second channel. Cover plates C may be welded to plate B and plate A or may be fixed by any mechanical means. Lateral spacer bars G are made in the first channel formed between plates A and B. The spacer bars could also have been implemented in the second channel.

[0093] There figure 4b illustrates the two cover plates D which are used to mechanically connect the two successive pairs of plates, arranged in a similar manner to the pairs shown in the figure 3b . Cover plates D are octagons having the shape of the cross-section of the second channel. Cover plates D can be welded to plate A and B or can be fixed by any other mechanical means. Spacer bars G are implemented in the first channel formed between plates A and B.

[0094] There figure 5 represents a stack of two pairs of heat exchanger plates according to the invention, in the “two junction panels” mode. Each pair consists of a plate A and a plate B, which are similar to the plates shown in the figure 2a. Plates A and B have been assembled and mechanically connected by their first joining panel. Between plate A and plate B is formed a first channel capable of receiving a first fluid F 1 . Spacer bars G are implemented in the first channel. Two pairs of identical spaced plates are superimposed and mechanically connected by their second joining panels. The channel formed between the first and second pair constitutes the second channel of the heat exchanger, which is capable of receiving a second fluid flow F 2 . The section of the second channel is not constant over the length of the channel. The closing means on each side of the second channel are not shown.

Claims

1. Pair of heat exchanger plates (A, B) comprising two heat exchanger plates that are spaced apart from one another, these being designated first (A) and second (B) heat exchanger plate, and of which the central panels (A0, B0) are parallel to one another (A; B), each of said plates comprising a central panel (A0; B0) with at least four sides (A1, A2, A3, A4; B1, B2, B3, B4), said central panel being preferably quadrilateral, or quadrilateral with truncated corners, and such that: - a first side (A1; B1) of the central panel is inclined with respect to said central panel (A0; B0) and forms a first joining panel (JA; JB), - the opposite side (A3; B3) to said first side (A1; B1) is flat, said pair of heat exchanger plates (A, B) being such that - the first joining panel (JA) of said first heat exchanger plate (A) and the first joining panel (JB) of said second heat exchanger plate (B) are arranged in such a way as to face one another, - the first joining panel (JA) of said first heat exchanger plate (A) is fastened directly to the central panel (B0) of said second heat exchanger plate (B) on said opposite flat side (B3), - the first joining panel (JB) of said second heat exchanger plate (B) is fastened directly to the central panel (A0) of said first heat exchanger plate (A) on said opposite flat side (A3), - said first joining panels (JA; JB) are made from a first part (A5; B5) and from a second part (A6; B6) extending from said first part, said first part forming an angle (α) with the central panel (A0; B0) and said second part being parallel to the central panel, - the space between said first (A) and second (B) heat exchanger plates forms a first canal for receiving a first flow of fluid (F1).

2. Pair of heat exchanger plates (A, B) according to Claim 1, wherein said first joining panel (JA; JB) comprises a first part forming an angle (α) with said central panel.

3. Pair of heat exchanger plates (A, B) according to either of Claims 1 and 2, wherein said angle (α) between the first part (A5; B5) of the first joining panel and the central panel (A0; B0) is comprised between 10° and 90°, preferably between 20° and 60°, and more preferably between 30° and 50°.

4. Pair of heat exchanger plates (A, B) according to one of the preceding claims, wherein: - a second side (A2; B2) of the central panel (A0; B0) is inclined with respect to the central panel, said second side being adjacent to the first side (A1; B1), and said second side forms a second joining panel (KA; KB) that is inclined in the opposite direction with respect to the first joining panel (JA; JB), - the opposite side (A4; B4) to said second side (A2; B2) is either flat or inclined in such a way as to form a third joining panel, said third joining panel being a mirror image of said second joining panel.

5. Pair of heat exchanger plates (A, B) according to Claim 4, wherein said second joining panel (A7) comprises a first part, notably a single part (A7; B7), said first part forming an angle (β) with the central panel.

6. Pair of heat exchanger plates (A, B) according to Claim 5, wherein said second joining panel (A7) is made from a first part (A7; B7) and from a second part (A8; B8) extending from said first part, said first part forming an angle (β) with the plane of the central panel (A0; B0) and said second part being parallel to the central panel.

7. Pair of heat exchanger plates (A, B) according to either of claims 5 and 6, wherein said angle (β) between the first part (A7; B7) of the second joining panel and the central panel (A0; B0) is comprised between 10° and 120°, preferably between 20° and 110°, and more preferably between 30° and 100°, or notably is 45° or 90°.

8. Stack of pairs of heat exchanger plates comprising two spaced-apart successive pairs of plates according to one of the preceding claims, designated first pair of heat exchanger plates and second pair of heat exchanger plates, wherein: - said first pair and said second pair are arranged parallel to one another, - the space between the first and the second pair of heat exchanger plates forms a second canal for receiving a second flow of fluid, and preferably said second pair is identical to said first pair or said second pair is a mirror image of said first pair.

9. Stack of pairs of heat exchanger plates (A, B) according to the preceding claim, forming a second canal for receiving a second flow of fluid, wherein said two successive spaced-apart pairs are connected laterally by closure means (C; D), said closure means preferably comprising an edge bar, a C-profile or U-profile cover plate, or a flat cover plate of hexagonal or pentagonal shape.

10. Stack of pairs of heat exchanger plates (A, B) according to Claim 8, said second pair preferably being identical to said first pair, comprising heat exchanger plates such that a second side (A2, B2) of their central panel is inclined with respect to the central panel (A0, B0), said second side (A2, B2) being adjacent to the first side (A1, B1) and said second side forming a second joining panel (KA; KB) that is inclined in the opposite direction with respect to the first joining panel (JA; JB), and the opposite side (A4; B4) to said second side (A2; B2) being flat, wherein: - the second joining panel of the second heat exchanger plate of the first pair is fastened directly to the central panel of the first heat exchanger plate of the second pair and the second joining panel of the first heat exchanger plate of the second pair is fastened directly to the central panel of the second heat exchanger plate of the first pair, - as an option, either closure means laterally connect said two pairs on the side of the second joining panels, or the corner zone at the intersection between the first and the second joining panel is formed in such a way as to mechanically connect said two pairs.

11. Stack of pairs of heat exchanger plates according to the preceding claim, comprising heat exchanger plates wherein said second joining panel of each plate of the stack comprises a part, notably a single part, said part forming an angle (β) with the central panel, or wherein said second joining panel of each plate of the stack is made from a first part and from a second part extending from said first part, said first part making an angle (β) with the central panel and said second part being parallel to the central panel.

12. Plate heat exchanger comprising pairs of heat exchanger plates or stacks of pairs of heat exchanger plates according to one of the preceding claims, said pairs or stack being arranged in a suitable casing.

13. Method for manufacturing a pair of heat exchanger plates according to one of Claims 1 to 7, said method comprising the following steps: - preparing two central panels, preferably quadrilateral, possibly truncated, comprising a first side and a second side adjacent to the first, - for each of said central panels, bending said first side in such a way as to form a first joining panel, said first joining panel comprising a first part, notably a single part, said first part forming an angle (α) with the central panel (A0; B0), - optionally, for each of said central panels, bending said second side in such a way as to form a second joining panel, said second joining panel comprising a first part, notably a single part, said first part forming an angle β with the central panel, - arranging the two heat exchanger plates in such a way that their first joining panels face one another and that their central plates are parallel to one another, - joining the two heat exchanger plates in such a way as to form a pair of plates, the space between the two plates forming a first fluid canal, - mechanically fastening the two plates along their first joining panels.

14. Method for manufacturing a stack of pairs of heat exchanger plates according to one of Claims 8 to 11, said method comprising the following steps: - preparing at least four central panels, preferably quadrilateral, possibly truncated, comprising a first side and a second side adjacent to the first, - for each of said central panels, bending said first side of the central panel in such a way as to form a first joining panel, said first joining panel comprising a first part, notably a single part, said first part forming an angle with the central panel, - optionally, for each of said central panels, bending said second side in such a way as to form a second joining panel, said second joining panel comprising a first part, notably a single part, said first part forming an angle β with the central panel, - arranging the heat exchanger plates in pairs in such a way that their first joining panels face one another and that their central plates are parallel to one another, - joining the heat exchanger plates in such a way as to form at least two pairs of plates, the space between the two plates forming a first fluid canal, - mechanically fastening the two plates of each pair along their first joining panels, - stacking the at least two pairs of plates, the space between the pairs of heat exchanger plates forming a second fluid canal, - optionally, mechanically fastening the two pairs of plates along their second joining panels.