Method for manufacturing a heat exchanger comprising a temperature probe

Abstract

This invention relates to a method for manufacturing a brazed plate-fin heat exchanger, comprising the steps of: a) stacking a set of plates parallel to each other and located longitudinally, such that a plurality of channels are defined between the plates for longitudinal flow of a first fluid to be heat-exchanged with a second fluid, the plates being bounded by a pair of longitudinally extending longitudinal edges and a pair of transversely extending transversely perpendicular to the longitudinal direction; b) forming the plates by stacking first and second flat products together along a stacking direction perpendicular to the longitudinal and transverse directions, at least one of the first and second flat products including a groove parallel to the plates and opening through at least one opening at a transverse or longitudinal edge to the outside of the stack; c) arranging a removable gasket in the groove; d) brazing the plates comprising brazing the first flat product to the second flat product; e) removing the gasket from the groove through the opening; f) introducing a temperature sensor into the groove. The invention also relates to a brazed plate-fin heat exchanger.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a brazed plate heat exchanger, the heat exchanger including at least one temperature sensor that allows for the measurement of temperature and / or heat flow inside the heat exchanger, and the present invention also relates to a heat exchanger that allows for the performance of these measurements.

[0002] This invention is particularly applicable to the field of cryogenic separation of gases, especially air, in apparatuses used for producing pressurized gaseous oxygen, known as ASUs (Air Separation Units). Specifically, the invention can be applied to the manufacture of heat exchangers that evaporate liquid streams, such as liquid oxygen, nitrogen, and / or argon, by exchanging heat with gaseous streams, such as air or nitrogen.

[0003] The invention can also be applied to heat exchangers that evaporate at least one liquid-gas mixture stream, particularly a multi-component mixture stream such as a hydrocarbon mixture, by exchanging heat with at least one other fluid, such as natural gas. Background Technology

[0004] The technology commonly used in heat exchangers is brazed plate heat exchanger technology, which allows for highly compact components, thus providing a large exchange surface area and low pressure loss. These heat exchangers are formed from a set of parallel plates, typically with spacer elements inserted between these plates, such as corrugated or wave-shaped structures that form finned heat exchange structures. The stacked plates together form a stack of flat channels to allow different fluids to enter the heat exchange relationship.

[0005] In manufacturing a heat exchanger, the plates, finned spacers and other components that form the heat exchanger are pressed together and then brazed together in a vacuum furnace at temperatures ranging from 550°C to 900°C.

[0006] Due to their compact size and overall structure, it is difficult to perform localized measurements of temperature or heat flow inside these brazed heat exchangers. Therefore, in the vast majority of the methods implemented, the operator can only obtain the total heat energy exchanged between the fluids by means of the energy balance achieved between the input and output of each fluid.

[0007] This makes it difficult to characterize these heat exchangers, and for example, it does not allow for individual measurement of the heat exchange coefficient for each of these channels.

[0008] During use, the lack of local data limits the controllability of this method. In particular, certain physical phenomena that may occur inside the heat exchanger, such as phase changes or chemical reactions, are represented by local variations in heat flow or temperature, which also depend on the location considered within the heat exchanger.

[0009] Localized temperature or heat flow measurements will allow for on-site detection of malfunctions in the heat exchanger: poor fluid distribution; performance degradation in certain areas of the heat exchanger due to phenomena such as blockage or localized distillation. It is also highly beneficial to monitor performance changes in a plate-fin heat exchanger throughout its service life by performing localized temperature or heat flow measurements.

[0010] In response to these requirements, it has been noted that existing temperature measurement solutions are not entirely satisfactory, particularly due to the complexity of the holding components used or their implementation.

[0011] "In-situ" temperature measurement methods exist, but currently only allow for the measurement of temperatures within the fluid itself. They are also invasive because they alter the flow of fluid within the exchange channels. Furthermore, since they are not provided during the construction of the heat exchanger, their implementation is relatively complex, expensive, and not very reliable.

[0012] Methods for measuring heat flow exist, but they involve inserting detectors between the channels of a heat exchanger. It is no longer possible to braze the heat exchanger as a single unit, meaning most of its advantages are lost. Furthermore, the detectors represent a significant additional cost and inevitably increase thermal resistance incompatible with the typical heat exchange coefficient of the heat exchanger under consideration. Finally, once a heat exchanger has a large number of channels, this approach becomes particularly difficult to consider on an industrial scale due to assembly difficulties.

[0013] Furthermore, a heat exchanger is known from document JP-A-2014169809, which includes a temperature sensor inserted into a tube, the tube itself being inserted into a groove made in a plate of the heat exchanger. The tube is brazed between two plates, and then the sensor is introduced into the tube. This method presents several problems. The presence of the tube inevitably increases the thermal resistance between the plate whose temperature is to be measured and the sensor, thereby reducing measurement accuracy. The tube also increases the space required to introduce the sensor, which increases the invasiveness of the method. Summary of the Invention

[0014] A particular objective of this invention is to overcome all or some of the aforementioned problems by providing a method for manufacturing brazed plate heat exchangers that allows for more accurate measurement of local temperature and / or heat flow within the heat exchanger in terms of both the measured value and its location within the heat exchanger, without disrupting the operation of the heat exchanger or increasing its space requirements.

[0015] Therefore, the subject of this invention is a method for manufacturing a brazed plate-fin heat exchanger, the method comprising the following steps:

[0016] a) A set of plates that are spaced apart and parallel to each other and located in a longitudinal direction, so as to define a plurality of channels between the plates, the plurality of channels being adapted for the flow of a first fluid to be heat-exchanged with at least one second fluid in the longitudinal direction, the plates being bounded by a pair of longitudinal edges extending in the longitudinal direction and a pair of transverse edges extending in a transverse direction perpendicular to the longitudinal direction.

[0017] b) At least one plate is formed by stacking at least a first flat product and a second flat product on top of each other along a stacking direction perpendicular to the longitudinal direction and the transverse direction, wherein at least one of the first flat product and the second flat product includes at least one groove, the at least one groove extending parallel to the plate and opening to the outside of the stack via at least one opening on the transverse edge or the longitudinal edge.

[0018] c) At least one removable gasket is arranged in the groove;

[0019] d) Brazing the assembly, including brazing the first flat product onto the second flat product;

[0020] e) Remove the removable gasket from the groove through the opening;

[0021] f) Introduce at least one temperature sensor into the groove.

[0022] Depending on the circumstances, the heat exchanger according to the invention may include one or more of the following features:

[0023] - The first flat product includes a first pair of opposing surfaces, the second flat product includes a second pair of opposing surfaces, the first flat product includes at least one groove, the at least one groove of the first flat product is exposed at the opposing surface of the first pair of opposing surfaces that is oriented toward the second flat product;

[0024] - The second flat product includes at least one groove, the at least one groove of the second flat product being arranged facing the at least one groove of the first flat product and exposed at the opposing surfaces of the second pair of opposing surfaces oriented toward the first flat product;

[0025] - In step b), the at least one plate is formed by stacking a first flat product, a second flat product and at least one additional flat product on top of each other, with the second flat product arranged between the first flat product and the additional flat product;

[0026] - The second flat product includes at least one groove, the at least one groove of the second flat product being exposed on one side at the opposing surface of the second pair of opposing surfaces oriented toward the first flat product, and on the other side at the opposing surface of the second pair of opposing surfaces oriented toward the additional flat product.

[0027] - The second flat product includes at least two grooves arranged at different heights along the stacking direction, one of the two grooves being exposed at the surface of the second pair of opposing surfaces oriented toward the first flat product, and the other of the two grooves being exposed at the surface of the second pair of opposing surfaces oriented toward the additional flat product.

[0028] - The pair of grooves are offset / misaligned relative to each other on a plane parallel to the plate;

[0029] - Recesses are formed on both sides of the at least one groove in the first flat product and / or the second flat product;

[0030] - A protrusion is provided on the inner wall of the at least one groove to locally reduce the cross-section of the groove;

[0031] - The at least one groove is exposed on one hand through an opening on a longitudinal edge or a transverse edge, and on the other hand through an opening on opposite longitudinal edges or opposite transverse edges, preferably, the openings are arranged on opposite longitudinal edges;

[0032] - At least one of the first flat product and the second flat product includes at least a plurality of grooves that converge at opposing longitudinal or transverse edges to be exposed via a common opening. Preferably, the plurality of grooves have a profile as a longitudinal section in a plane parallel to the plate, the profile having at least one curved portion.

[0033] - The first flat product and the second flat product include, on at least one of their opposing surfaces, a coating or sheet made of a brazing material having a predetermined melting temperature, the removable gasket being wholly or partially made of a first material having a melting temperature higher than the predetermined melting temperature, or the removable gasket being wholly or partially covered by a coating product configured to form a diffusion barrier layer of the brazing material in the first material of the removable gasket in step d).

[0034] - Step e) includes at least one of the following sub-steps: i) applying a traction force to the removable gasket to cause translational movement of the removable gasket toward the outside of the stack; ii) causing a torsional movement of the removable gasket to cause deformation of at least a portion of the removable gasket; iii) heating or cooling the removable gasket.

[0035] - After or simultaneously with step f), a second material is introduced into the groove and then the second material is melted to fill at least a portion of the space around the temperature detector. Preferably, the melting temperature of the second material is less than or equal to 500°C, more preferably less than or equal to 200°C, and more preferably less than or equal to 100°C.

[0036] Furthermore, the present invention relates to a brazed plate-fin heat exchanger comprising a set of plates parallel to each other and located in a longitudinal direction to define a plurality of channels between the plates, the plurality of channels being adapted for the flow of a first fluid to exchange heat with at least one second fluid, the plates being bounded by a pair of longitudinal edges extending in the longitudinal direction and a pair of transverse edges extending in a transverse direction perpendicular to the longitudinal direction, at least one of the plates being formed of at least a first flat product and a second flat product, the first flat product and the second flat product being brazed together and stacked vertically on top of each other in a stacking direction perpendicular to the longitudinal direction and the transverse direction. At least one of the first flat product and the second flat product includes at least one groove, the at least one groove extending parallel to the plate and opening to the outside of the laminate via at least one opening on the lateral edge or longitudinal edge—preferably via at least one opening on the longitudinal edge—wherein at least one temperature sensor is arranged in the groove, and a second material is arranged around at least a portion of the temperature sensor, the second material having a melting temperature of less than or equal to 500°C, preferably less than or equal to 200°C, more preferably less than or equal to 100°C, and there is no other mechanism in the groove for holding the temperature sensor in the groove.

[0037] Specifically, the at least one plate is formed by stacking a first flat product, a second flat product, and at least one additional flat product on top of each other, the second flat product being disposed between the first flat product and the additional flat product, the second flat product including at least one groove, the second flat product including at least two grooves disposed at different heights along the stacking direction, wherein each groove includes at least one detector, one of the two grooves being exposed at a surface of the second pair of opposing surfaces oriented toward the first flat product, and the other of the two grooves being exposed at a surface of the second pair of opposing surfaces oriented toward the additional flat product.

[0038] Furthermore, at least one of the first flat product and the second flat product may include at least two recesses exposed on opposite lateral or longitudinal edges, each recess being inclined at an angle in the range of 0° to 90°, preferably in the range of 10° to 80°, relative to the lateral or longitudinal edge exposed thereon. Attached Figure Description

[0039] The invention will now be made more readily apparent through the following description, which is provided only by way of non-limiting example and with reference to the accompanying drawings, wherein:

[0040] Figure 1 This is a three-dimensional view of a brazed plate heat exchanger that can be manufactured using the method according to the present invention;

[0041] Figure 2 Various embodiments of the flat product and groove according to the present invention are illustrated schematically;

[0042] Figure 3 Other embodiments of the flat product and groove according to the present invention are illustrated schematically;

[0043] Figure 4 Other embodiments of the flat product and groove according to the present invention are illustrated schematically;

[0044] Figure 5 Other embodiments of the flat product and groove according to the present invention are illustrated schematically;

[0045] Figure 6 A flat product comprising a plurality of grooves is schematically shown according to an embodiment of the present invention;

[0046] Figure 7 A flat product according to another embodiment of the present invention is illustrated schematically. Detailed Implementation

[0047] Figure 1 A brazed plate-fin heat exchanger 1 is shown, comprising a stack of plates 2 extending in both length and width along the longitudinal direction z and the transverse direction x, respectively. The plates 2 are stacked parallel to each other and spaced apart. Together, they form multiple sets of channels 3, some of which are configured for the flow of a first fluid F1, and others for the flow of at least one other fluid F2, F3, which will indirectly exchange heat with the first fluid F1 via the plates 2. The transverse direction x is orthogonal to the longitudinal direction z and parallel to the plates 2. The fluids preferably flow along the length of the heat exchanger parallel to the longitudinal direction z.

[0048] Preferably, each channel has a flat, parallelepiped shape. The gap between two successive plates 2 is small compared to the length and width of each successive plate, and this gap corresponds to the height of the channel measured in the stacking direction y of the plates 2. The stacking direction y is orthogonal to the plates.

[0049] Channel 3 is defined by a sealing rod 6, which does not completely block the channel but leaves a free opening for the input / output / exit of the corresponding fluid. Plate 2 is demarcated by preferably paired parallel peripheral edges 4. The peripheral edges 4 include a pair of longitudinal edges 4a extending in the longitudinal direction z and a pair of transverse edges 4b extending in the transverse direction x.

[0050] The heat exchanger 1 includes semi-tubular manifolds 7 and 9, which are provided with inlets and outlets 10 for introducing fluid into the heat exchanger 1 and for discharging fluid from the heat exchanger 1. These manifolds have openings narrower than the channels. Distribution zones arranged downstream of the inlet manifolds and upstream of the outlet manifolds are used to uniformly guide fluid to or from the entire width of the channels.

[0051] Preferably, at least a portion of the channel 3 includes a finned spacer element 8, which advantageously extends parallel to the plate 2 along the width and length of the channel of the heat exchanger. In the example shown, the spacer element 8 comprises a heat exchange corrugated element in the form of a corrugated sheet. In this context, "fin" refers to a corrugated leg connecting successive peaks / tops and troughs / bottoms of the corrugated element. The spacer element 8 may also take other specific shapes defined according to desired fluid flow characteristics. More generally, the term "fin" encompasses blades or other auxiliary heat exchange surfaces that extend from the main heat exchange surface, i.e., the plate of the heat exchanger, into the channel of the heat exchanger.

[0052] In manufacturing the heat exchanger 1, a set of plates 2 are provided, which are stacked / layered parallel to each other and parallel to the longitudinal direction z. The plates 2 are spaced apart from each other by closing rods 6. After assembling other components of the heat exchanger, particularly the exchange corrugations, distribution corrugations, etc., the stacked components are brazed to fix the components of the heat exchanger together. Preferably, the plates of the heat exchanger and all or some of the other components are made of aluminum or aluminum alloy.

[0053] According to the invention, at least one of the plates 2 of the heat exchanger is formed by stacking at least a first flat product 21 and a second flat product 22 on top of each other. The first flat product 21 and the second flat product 22 are brazed together, and also brazed together with other plates 2, which are also brazed together. Preferably, the plates 2 formed by stacking flat products and the other plates 2 of the heat exchanger are brazed simultaneously. It is also conceivable to braze the flat products together, then stack them together with other plates 2, and braze the stack.

[0054] from Figure 2 As can be seen in the example, at least one of the first flat product 21 and the second flat product 22 includes at least one groove 12. A groove is also understood to be a slot, slit, or recess formed in the thickness of the plate 2. The groove 12 extends parallel to the plate 2 and, depending on which flat product the groove is located on, leads to the exterior of the laminate via at least one opening 5 located on the lateral edge 4b ​​or longitudinal edge 4a of the first or second flat product. When the first and second flat products overlap, the groove 12 forms a cavity located inside the plate 2 formed by the products 21, 22, which is configured to subsequently accommodate at least one temperature sensor 14. It should be noted that... Figures 2 to 5 A perforated straight corrugated element 8 is shown arranged in channels on both sides of plate 2 of a heat exchanger. Of course, any type of corrugated element can be conceived, especially a straight corrugated element without perforations, a herringbone corrugated element also called a "wavy" corrugated element, a partially offset corrugated element, etc.

[0055] Within the scope of this invention, the temperature detector 14 can be any detector configured to perform temperature measurement by contact. In particular, the temperature detector 14 can be a resistance temperature detector, such as a resistance detector, especially a platinum resistance detector of the PT100 type, or even a thermocouple or thermistor temperature detector. It should be noted that the detector 14 introduced into the recess refers at least to the thermistor component of the sensor system, particularly the measuring junction between the two wires of a resistance circuit or thermocouple in the case of resistance measurement, also known as a thermal weld. Other sensor components required for measurement (particularly power supply equipment, voltage measuring equipment) are arranged outside the stack and connected to the detector 14 by suitable wires such as copper wire, thermocouple, or extension / compensation cable. In the case of using a thermocouple temperature detector 14, the detector 14 may include two conductive wires brazed at one end to form a measuring junction, wherein the conductive wires are arranged in the recess 12 either exposed or in the form of a protective sleeve, typically cylindrical.

[0056] During brazing, the components of the heat exchanger are connected by brazing using a filler metal / solder called brazing filler metal or brazing material 30, which has a predetermined melting temperature. Preferably, the predetermined melting temperature is 550°C to 900°C, more preferably 550°C to 650°C.

[0057] This assembly is achieved by melting or diffusing (without melting) brazing materials 30 inside the parts to be brazed. The brazing materials 30 may be in the form of a coating typically deposited by co-lamination, or optionally in the form of a liquid coating or gel deposited manually on the surface of the plates, or in the form of sheets or strips disposed between the plates. The plates, finned spacers, and other components of the heat exchanger are pressed together by a compression device that applies a compressive force to the plates 2, typically at 20,000 N / m. 2 Up to 40,000 N / m 2 Within the specified range. The laminate is introduced into a vacuum furnace and brazing can be performed in a temperature range of 550°C to 900°C, preferably in a temperature range of 550°C to 650°C.

[0058] To prevent the brazing material 30 from filling the groove 12 during melting, at least one removable gasket 11 is arranged in the groove 12. It should be noted that the removable gasket 11 can be placed in the groove 12 via the opening 5 before or after the flat products are stacked. Preferably, considering the subsequent brazing process of the laminate, the gasket 11 is placed in the groove after the flat products have been stacked and held together by compressive force. This ensures that the flat products are in sufficient contact with each other before the gasket is introduced, and this avoids movement of the laminated elements during the insertion of the gasket 11, which could damage the integrity of the brazing substrate and thus impair the operation of the heat exchanger. This also allows verification that the size of the gasket is not too large relative to the size of the groove.

[0059] It should be noted that if there are multiple grooves 12, each groove 12 may be provided with at least one removable gasket 11. The removable gaskets may be separated from each other, or even all or some of the gaskets may be connected together, for example, like a comb, where the teeth will form the gaskets, and the common part of the connecting teeth is arranged on the outside of the stack.

[0060] Brazing of the plate 2 is performed with the removable gasket 11 placed in the groove 12. Preferably, the removable gasket 11 is made wholly or partially of a first material having a melting temperature higher than the predetermined temperature. Therefore, the removable gasket 11 is not brazed to the flat product and can subsequently be easily removed, reducing the risk of damage or deformation to the flat product in which the removable gasket is inserted. For example, the first material can be an iron alloy such as stainless steel. The brazing material 30 is preferably aluminum or an aluminum alloy.

[0061] Alternatively or additionally, the removable gasket 11 may be completely or partially covered with a coating product configured to form a diffusion barrier layer of solder material 30 in the first material of the removable gasket 11 during step d). This allows for gasket removal by limiting solder adhesion / adhesion. Therefore, the method may include the use of, for example... The step of covering the pad 11 with boron nitride products is to prevent or limit the solder during the brazing stage.

[0062] Another conceivable removable gasket 11 comprises an inner portion formed of a second material and an outer portion formed of a first material, wherein the melting temperature of the second material is lower than that of the first material. The outer portion serves as an insulator to prevent the inner portion from being brazed to an adjacent flat product. Therefore, greater freedom is available in the selection of the material for the inner portion, which may optionally have a melting temperature less than or equal to a predetermined melting temperature. For example, the outer portion may be formed / made of an iron alloy, particularly stainless steel. The inner portion may be formed / made of aluminum or an aluminum alloy.

[0063] The removable gasket 11 can be a solid or hollow component in the form of a rod or tube, and can have different cross-sectional shapes, especially circular, square, hexagonal, etc.

[0064] After the laminated components are assembled by brazing, the removable gasket 11 is removed from the recess 12 via opening 5, and the temperature detector 14 is introduced into the recess 12, which has been emptied by removing the gasket 11. The temperature detector 14 can be directly inserted into the recess without the need for an intermediate retaining component between the detector and the first and second flat products. This minimizes the thermal resistance between the detector and the flat products, thereby significantly improving measurement accuracy. Furthermore, brazing the first and second flat products together ensures excellent contact from a thermal perspective and minimizes the thermal resistance between the two components, thus avoiding adverse effects on the performance of the heat exchanger during operation. The temperature detector is introduced into the heat exchanger non-invasively. The detector is contained within the plate 2 of the heat exchanger, which allows for the measurement of localized temperatures within the heat exchanger. The space requirements of the device are also minimized.

[0065] Figure 2 Several different embodiments of the flat product and the groove are shown. In particular, the groove 12 may have a square, rectangular, or semi-circular cross-section, which is a transverse section in a plane orthogonal to the longitudinal direction z.

[0066] The shape of the groove can be adjusted according to the shape of the detector 14 to be accommodated. The depth of the groove 12 and / or the thickness of the flat product can also be adjusted to accommodate the size of the detector 14 and place the detector 14 at a predetermined height within the plate 2, wherein the height is measured parallel to the stacking direction y.

[0067] The flat products together form a plate 2, and spacer elements 8 are arranged in fluid channels formed on both sides of the plate 2. The first flat product 21 includes a first pair of opposing surfaces 21a, 21b, and the second flat product 22 includes a second pair of opposing surfaces 22a, 22b. For simplicity, these surfaces are only... Figure 2 (a) Marked in the middle.

[0068] Preferably, brazing material 30 is arranged between the plates 2 and between the flat products.

[0069] Preferably, at least one surface of the flat product facing the spacer element 8 and at least one surface of the flat product facing another flat product comprise brazing material 30. Alternatively, both surfaces of the two flat products facing each other comprise brazing material 30.

[0070] Figure 2 (a) shows the first flat product 21 with the groove 12 exposed on its surface 21a facing the second flat product 22. Brazing material 30 is disposed on the surface 22b of the second flat product 22 oriented towards the groove 12. According to... Figure 2 (b) shows another possibility where the brazing material 30 is disposed on the exposed surface 21a of the groove 12. In this case, it is preferable to avoid having the brazing material 30 near the groove 12 in order to limit the amount of brazing material entering the groove 12 during brazing. If the brazing material is applied to the first planar component, machining a groove on that surface allows for the removal of the brazing material. If the brazing material is in the form of a sheet placed between two flat products, the sheet is arranged to ensure that it does not extend into the groove 12.

[0071] Figure 2 (e) shows a gasket 11 with a square or circular cross-section.

[0072] According to one possibility, such as Figure 2 As shown in (d), the second flat product 22 may also include at least one recess 12, which is arranged facing the at least one recess 12 of the first flat product 21 and exposed at the opposing surface 22b oriented toward the first flat product 21 in the second pair of opposing surfaces. Advantageously, the two recesses 12 have a semi-circular cross-section. This configuration is particularly suitable for mounting cylindrical detectors 14.

[0073] exist Figure 2In the case shown in (c), the plate 2 in which temperature measurement is performed is formed by stacking a first flat product 21, a second flat product 22, and an additional flat product 23 on top of each other. The second flat product 22 is arranged between the first flat product 21 and the additional flat product 23.

[0074] According to one embodiment, the second flat product 22 includes a through slot 12. This allows for precise control of the symmetrical positioning of the detector within the plate when it is desired to measure the temperature at the center of the plate 2.

[0075] according to Figure 4 In another embodiment shown, the second flat product 22 includes at least two recesses 12, one recess exposed at the opposing surface 22b of the second pair of opposing surfaces oriented toward the first flat product 21, and the other recess exposed at the opposing surface 22a of the second pair of opposing surfaces oriented toward the additional flat product 23. This allows two temperature detectors 14 to be mounted at different heights within the plate 2. Based on the temperature difference measured by each of these detectors, the heat flow through the plate 2, which acts as a thermal resistance, can be deduced. Preferably, the two recesses 12 are located on both sides and equidistant from the central plane of the plate 2, which is a plane parallel to the plate 2 of the stack and arranged in the stacking direction y at the center of the plate 2 formed by the stack of flat products 21, 22, 23. The subsequently arranged detectors are also positioned in this manner. This allows the measurement of the temperature difference generated through the plate, which directly or indirectly leads to the determination of the heat flow through the plate.

[0076] The thickness of the second flat product 22 into which the detectors are inserted, the distance between the detectors, and their accuracy can be selected to correspond to the desired measurement position and sensitivity.

[0077] According to one possibility, such as Figure 4 As shown in (a), the grooves 12 in the pair of grooves are arranged overlapping each other, but at different heights within the plate 2. Therefore, the subsequently inserted detectors 14 are positioned facing each other. Thus, the temperature difference between the two detectors is a function of the heat flow perpendicular to the intermediate plane.

[0078] According to another possibility, such as Figure 4 As shown in (b), the grooves 12 are offset / misaligned relative to each other in a plane parallel to plate 2. This allows for the use of a thinner second flat product, and thus allows for limiting the thermal resistance of the second flat product, and avoids any impact on the performance of the heat exchanger.

[0079] According to another possibility, such as Figure 4As shown in (c), more than two detectors 14 can be arranged at different heights inside the plate formed by the flat products using multiple additional flat products. In practice, as many additional flat products as are required into the laminate can be added. This allows for the use of more than two measurement points to measure the thermal gradient, thereby further improving measurement accuracy. This arrangement is also more reliable and makes it possible to detect if one of the detectors is faulty.

[0080] Therefore, in Figure 4 In example (c), two additional flat products 23, 24 are stacked on top of the second flat product 22. One of the additional flat products 23, 24 includes at least one recess 12, which is exposed toward the other additional flat product 23, 24. This stacking pattern allows three (3) detectors to be arranged one on top of the other.

[0081] Figure 3 Other possible arrangements of flat products, which are stacked to form the plate 2 according to the invention, are schematically shown. Figure 3 As shown in (b) and (c), recesses 120, such as cutouts or slots, may be formed on both sides of the at least one recess 12 in the first flat product 21 and / or the second flat product 22. This allows any excess solder to be collected during the brazing stage and thus allows the integrity of the housing / cavity provided for the detector to be maintained.

[0082] When the brazing material is not co-laminated onto the flat product, the brazing material can only be placed at a certain distance from the groove 12, such as... Figure 3 As shown in (a). If the flat product is already covered with brazing material, the opening of the groove 12 may include the step of removing the brazing material on both sides of the groove within a certain distance.

[0083] Figure 5 An embodiment is schematically illustrated in which a protrusion 121 is provided on the inner wall of the groove 12 to locally reduce the cross-section of the groove 12. This makes the detector easier to slide during its introduction by reducing the contact area between the detector and the inner wall of the groove. This also facilitates the removal of the removable gasket 11 after brazing. It should be noted that at least one surface portion of the inner wall may also have surface micro-protrusions / roughness.

[0084] Because these localized contractions reduce the thermal contact between the detector and the plate, they can be omitted or removed from the areas where the temperature must be measured, thus improving the representativeness of the measurement. For example, since plate 2 has very different temperatures in the areas where it is preferably insulated and in the areas where the temperature is to be measured, the protrusions in the areas where it is preferably insulated can also be larger / enlarged.

[0085] It should be noted that the at least one groove 12 may be exposed via a single opening located on the edge of the plate 2, or the at least one groove 12 may be exposed on one hand via an opening 5 on a longitudinal edge 4a or a transverse edge 4b, and on the other hand via openings 5 ​​on opposite longitudinal edges 4a or transverse edges 4b. Preferably, the openings 5 ​​are arranged on two opposite longitudinal edges 4a. Thus, the groove 12 passes through areas with substantially equal temperatures, which avoids localized disruption of the temperature field due to increased heat from the detector itself.

[0086] Alternatively, two pads 11 can be arranged in the groove 12, each pad being removed through one of the openings 5, and / or two detectors 14 can be placed in the groove 12, each detector being inserted through one of the openings 5.

[0087] If one and / or another flat product includes multiple grooves, each groove may be exposed on at least one edge of the heat exchanger through a separate corresponding opening. The multiple grooves 12 may also converge at opposing longitudinal edges 4a or transverse edges 4b to be exposed through a common opening 5. This is in Figure 6 As shown in the figure. These grooves may stop inside the plate 2 (on the left-hand side of the plate) or be exposed through a plurality of different corresponding openings 5 ​​provided along the opposite edge (on the right-hand side of the plate).

[0088] Figure 6 The possible profile of the groove 12 as a longitudinal section in a plane parallel to plate 2 is schematically shown. Preferably, each groove includes a straight section. Each groove may include multiple straight sections and optionally at least one curved section, the multiple straight sections forming an angle between them. This allows multiple grooves to be combined at the same opening 5. These grooves 12 may be at least partially parallel to each other. This arrangement of multiple grooves allows for the measurement of temperature and heat flow at different locations along the length of the heat exchanger, in particular for determining where different reactions or phase transitions occur. Thus, a diagram of the physicochemical phenomena that may occur in the heat exchanger is obtained.

[0089] During step e), when removing the removable gasket 11, a traction force is preferably applied to the gasket 11 to induce a translational movement thereon toward the outside of the laminate. Preferably, the traction force is oriented in a direction substantially parallel to the plate 2 and perpendicular to the extension direction of the edge on which the opening 5 is arranged.

[0090] Alternatively, the removable pad 11 may be arranged in the recess 12 such that a portion of the pad 11 extends beyond the opening 5 toward the outside of the laminate. Thus, the portion extending beyond the intended edge forms a manual or mechanical gripping portion that facilitates removal.

[0091] A torsional motion can also be applied to the removable gasket 11 to cause deformation of at least a portion of the removable gasket 11. This deformation allows for a reduction in cross-sectional area and thus facilitates its pull-out. A gasket 11 in the form of a hollow tube is preferred.

[0092] The removable gasket 11 can be deformable, which facilitates translational movement and removal, thereby reducing the risk of damage or deformation to the plate 2 into which the gasket is inserted.

[0093] Preferably, the removable gasket 11 is configured to undergo complete or partial plastic deformation, i.e., irreversible deformation. This further facilitates the removal of the support member, as it eliminates the need for continuous torque application.

[0094] The removal step may also include heating the removable gasket 11. Specifically, the gasket can be significantly and locally heated by circulating an electric current through it. The heat causes the gasket to expand, subsequently cooling it, which creates clearance in the groove 12 required for moving the gasket. The heat may also cause localized remelting of the solder that may have remained on the gasket during brazing.

[0095] The removal step may also include cooling the removable pad 11, which creates clearance in the groove 12 for moving the pad through differential contraction.

[0096] Alternatively, in step d), the gasket 11 can be brought into contact with a product configured to dissolve the constituent material of the gasket. However, the product is configured not to dissolve the material forming plate 2.

[0097] It should be noted that, preferably, the height of the shim 11 prior to the removal step is such that it extends to almost the entire height, or even the entire height, of the groove 12 in the stacking direction y, so that there is little or no play between the shim 11 and the adjacent plate 2. This allows the introduction of solder into the groove 12 during brazing to be limited.

[0098] Optionally, after or simultaneously with inserting the temperature sensor 14 into the recess 12, at least one element, such as a wire, may be introduced into the recess. This element is made of a second material having a relatively low melting temperature, i.e., less than or equal to 500°C, preferably less than or equal to 200°C, and more preferably less than or equal to 100°C. The second material may be selected from metals or metal alloys containing at least one of the following metals: indium, bismuth, tin, lead, cadmium, and gallium. More generally, the second material can be any thermally conductive material, and therefore thermally conductive adhesive may be considered.

[0099] The heating element is then heated and melted around the detector, allowing for good thermal contact between the heat exchanger and the detector, even when using irregularly shaped detectors or when the detector is formed from bare wires joined together. In other words, at least a portion of the space remaining between the detector and the inner wall of the recess is filled with a second material.

[0100] Alternatively, liquid second material can be poured into groove 12 around detector 14.

[0101] Figure 7 An embodiment is illustrated schematically in which one of the first and second flat products includes at least two recesses 12 exposed on opposite lateral edges 4b or longitudinal edges 4a. Figure 7 This illustrates a configuration where the grooves extend toward the center of the flat product and stop at the same position z1 along the length of the heat exchanger. It is also conceivable that the grooves 12 could stop at different heights. Each groove 12 is inclined at an angle A ranging from 0° to 90° relative to its exposed transverse edge 4b ​​or longitudinal edge 4a. Therefore, it is feasible to arrange the second material at once and then melt or pour it directly into all the grooves 12 located on each opposite edge without rotating the flat product and filling the grooves one by one. This facilitates the flow of the second material into the grooves. Preferably, the angle A is at least 5°, preferably in the range of 10° to 80°, and more preferably in the range of 20° to 60°.

[0102] This invention allows for the measurement of local heat flux and / or local temperature, and thus allows for the determination of local heat exchange coefficients, providing information related to the local operating conditions of the heat exchanger. The method for assembling the detector is relatively simple and non-invasive.

[0103] Of course, the invention is not limited to the specific examples described and shown in this application. Other variations or embodiments falling within the scope of the invention as defined by the appended claims will also be apparent to those skilled in the art without departing from the scope of the invention. In particular, it should be noted that the plurality of plates 2 of the heat exchanger 1 may be formed of a flat product and may have at least one groove 12 according to the invention. These plates may have different constructions, particularly different numbers and / or different groove shapes, different numbers of openings, and openings arranged on different edges.

Claims

1. A method for manufacturing a brazed plate-fin heat exchanger (1), the method comprising the following steps: a) A set of plates (2) are stacked at intervals, parallel to each other and located in the longitudinal direction (z) to define a plurality of channels (3) between the plates (2), the plurality of channels being adapted for the flow of a first fluid to be heat-exchanged with at least one second fluid along the longitudinal direction (z), the plates (2) being bounded by a pair of longitudinal edges (4a) extending in the longitudinal direction (z) and a pair of transverse edges (4b) extending in a transverse direction (x) perpendicular to the longitudinal direction (z); b) At least one plate (2) stacked in step a) is formed by stacking at least a first flat product (21) and a second flat product (22) on top of each other along a stacking direction (y) perpendicular to the longitudinal direction (z) and the transverse direction (x), wherein at least one of the first flat product (21) and the second flat product (22) includes at least one groove (12) extending parallel to the plate (2) and opening to the outside of the stacked member via at least one opening (5) of the transverse edge (4b) or the longitudinal edge (4a); c) At least one removable gasket (11) is arranged in the groove (12). d) Brazing the assembly (2) includes brazing the first flat product (21) onto the second flat product (22); e) Remove the removable gasket (11) from the groove (12) through the opening (5); f) Introduce at least one temperature detector (14) into the groove (12).

2. The method according to claim 1, characterized in that, The first flat product (21) includes a first pair of opposing surfaces (21a, 21b), the second flat product (22) includes a second pair of opposing surfaces (22a, 22b), the first flat product (21) includes at least one groove (12), the at least one groove of the first flat product is exposed at an opposing surface (21a) of the first pair of opposing surfaces oriented toward the second flat product (22).

3. The method according to claim 2, characterized in that, The second flat product (22) includes at least one groove (12) which is arranged facing the at least one groove (12) of the first flat product (21) and exposed at the opposing surface (22b) of the second pair of opposing surfaces oriented toward the first flat product (21).

4. The method according to any one of claims 1-3, characterized in that, In step b), the at least one plate (2) is formed by stacking a first flat product (21), a second flat product (22) and at least one additional flat product (23, 24) on top of each other, with the second flat product (22) arranged between the first flat product (21) and the additional flat product (23).

5. The method according to claim 4, characterized in that, The second flat product (22) includes at least one groove (12) which is exposed on one hand at the opposing surface (22b) of the second pair of opposing surfaces oriented toward the first flat product (21), and on the other hand at the opposing surface (22a) of the second pair of opposing surfaces oriented toward the additional flat product (23).

6. The method according to claim 4, characterized in that, The second flat product (22) includes at least two grooves (12) arranged at different heights along the stacking direction (y), one of the two grooves being exposed at the opposing surface (22b) of the second pair of opposing surfaces oriented toward the first flat product (21), and the other of the two grooves being exposed at the opposing surface (22a) of the second pair of opposing surfaces oriented toward the additional flat product (23).

7. The method according to claim 6, characterized in that, The two grooves (12) are offset relative to each other in a plane parallel to the plate (2).

8. The method according to any one of claims 5-7, characterized in that, Recesses (120) are formed on both sides of the at least one groove (12) in the first flat product (21) and / or the second flat product (22).

9. The method according to any one of claims 1-3, characterized in that, A protrusion (121) is provided on the inner wall of the at least one groove (12) for locally reducing the cross-section of the groove (12).

10. The method according to any one of claims 1-3, characterized in that, The at least one groove (12) is exposed on one hand through an opening (5) of a longitudinal edge (4a) or a transverse edge (4b), and on the other hand through an opening (5) of an opposite longitudinal edge (4a) or an opposite transverse edge (4b).

11. The method according to any one of claims 1-3, characterized in that, Step e) includes at least one of the following sub-steps: i) Apply a traction force to the removable gasket (11) so as to make the removable gasket translate toward the outside of the stack; ii) To cause the removable gasket (11) to twist so as to cause at least a portion of the removable gasket (11) to deform; iii) Heating or cooling the removable gasket (11).

12. The method according to any one of claims 1-3, characterized in that, After step f), a second material is introduced into the groove (12) and then the second material is melted to fill at least a portion of the space around the temperature detector (14).

13. The method according to claim 10, characterized in that, The openings (5) are arranged on the two opposite longitudinal edges (4a).

14. The method according to claim 12, characterized in that, The melting temperature of the second material is less than or equal to 500°C.

15. The method according to claim 12, characterized in that, The melting temperature of the second material is less than or equal to 200°C.

16. The method according to claim 12, characterized in that, The melting temperature of the second material is less than or equal to 100°C.

17. A brazed plate-fin heat exchanger comprising a set of plates (2) parallel to each other and located in a longitudinal direction (z) to define a plurality of channels (3) between the plates (2), the plurality of channels being adapted for flow of a first fluid to exchange heat with at least one second fluid, the plates (2) being bounded by a pair of longitudinal edges (4a) extending in the longitudinal direction (z) and a pair of transverse edges (4b) extending in a transverse direction (x) perpendicular to the longitudinal direction (z), at least one of the plates (2) being at least made of a first flat product (21) and a second flat product (22) are formed, the first flat product and the second flat product being brazed together and stacked one on top of the other along a stacking direction (y), the stacking direction being perpendicular to the longitudinal direction (z) and the transverse direction (x), at least one of the first flat product (21) and the second flat product (22) including at least one groove (12), the at least one groove extending parallel to the plate (2) and opening to the outside of the stacked member via at least one opening (5) of the transverse edge (4b) or the longitudinal edge (4a), wherein, At least one temperature detector (14) is arranged in the groove (12), and a second material is arranged around at least a portion of the temperature detector (14), the second material having a melting temperature of less than or equal to 500°C, and there is no other mechanism in the groove (12) for holding the temperature detector (14) in the groove (12).

18. The brazed plate-fin heat exchanger according to claim 17, characterized in that, The melting temperature of the second material is less than or equal to 200℃.

19. The brazed plate-fin heat exchanger according to claim 17, characterized in that, The melting temperature of the second material is less than or equal to 100℃.

20. The brazed plate-fin heat exchanger according to claim 17, characterized in that, The at least one plate (2) is formed by stacking a first flat product (21), a second flat product (22) and at least one additional flat product (23, 24) on top of each other, the second flat product (22) being arranged between the first flat product (21) and the additional flat product (23), the second flat product (22) including at least two grooves (12) arranged at different heights along the stacking direction (y), wherein each groove (12) includes at least one temperature sensor (14), one of the two grooves being exposed at a second pair of opposing surfaces oriented toward the first flat product (21) on an opposing surface (22b), and the other of the two grooves being exposed at a second pair of opposing surfaces oriented toward the additional flat product (23) on an opposing surface (22a).

21. The brazed plate-fin heat exchanger according to any one of claims 17-20, characterized in that, At least one of the first flat product (21) and the second flat product (22) includes at least two grooves (12) exposed on opposite lateral edges (4b) or longitudinal edges (4a), each groove (12) being inclined at an angle (A) relative to the lateral edge (4b) or longitudinal edge (4a) on which the groove (12) is exposed, the angle being in the range of 0° to 90°.

22. The brazed plate-fin heat exchanger according to claim 21, characterized in that, The angle is in the range of 10° to 80°.

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