Method for producing a plate heat exchanger and plate heat exchanger with thermocouple or measuring resistor

Abstract

The invention relates to a method for producing a plate heat exchanger (1) having a plurality of spacers (20) and a plurality of fins (11, 12), the fins being arranged in each case between two adjacent spacers, wherein at least one capillary tube (30) having at least one thermocouple and / or measuring resistor element (40) is introduced into at least one spacer (20), and wherein the spacers of the plurality of spacers and the fins of the plurality of fins are in each case arranged alternately and connected to one another in a material-bonded manner; and to a plate heat exchanger (1) produced in such a manner.

Description

[0001] The invention relates to a method for producing a plate heat exchanger and a plate heat exchanger having a plurality of spacers and a plurality of fins, wherein each fin is arranged between two adjacent spacers. Existing technology

[0002] A plate heat exchanger has a number of spacers or dividing plates arranged parallel to one another, and a number of fins. A fin is placed between each pair of adjacent spacers, creating parallel channels between adjacent plates through which a medium can flow. These fins are laterally delimited by so-called side bars, which are brazed to adjacent plates. This creates a number of parallel heat exchange channels, allowing the media to flow past one another, for example, in countercurrent, for indirect heat exchange.

[0003] Thermal stresses caused by differential thermal expansion due to different temperature differences can mechanically degrade the integrity of the seals between heat exchange channels to the point where the plate heat exchanger leaks relative to its surroundings. To analyze the temperature field, such plate heat exchangers may be equipped with temperature measuring devices, for example, on their outer surfaces. However, the temperature on the outer surface only provides a local value from which assumptions can be made about the temperature inside the plate heat exchanger. However, since the measurements occur on the outer surface, these temperature measurements may be affected by the environment.

[0004] WO 2014 / 056587 A1 describes, for example, a plate heat exchanger with an optical waveguide for temperature measurement. In this case, the optical waveguide is arranged in an open groove provided in the fins or webs of the plate heat exchanger.

[0005] It is desirable to provide an improved possibility for temperature measurement in plate heat exchangers. Summary of the Invention

[0006] Against this background, the present invention proposes a method for producing a plate heat exchanger having the features of the invention, and a plate heat exchanger having a plurality of webs and a plurality of fins, each of which is arranged between two adjacent webs. Advantageous configurations are the subject of the technical solution of the invention and the subsequent description thereof.

[0007] Within the scope of the method according to the present invention for producing a plate heat exchanger, at least one capillary tube having at least one thermocouple and / or measuring resistor element is introduced into at least one of the plurality of spacers. The spacers of the plurality of spacers and the fins of the plurality of fins are each arranged alternately and materially bonded to one another. Thus, a fin is each arranged between two spacers extending parallel to one another.

[0008] The invention is based on the recognized idea of introducing at least one thermocouple in a capillary tube and / or one measuring resistor element in at least one spacer of a plate heat exchanger and using it to monitor the temperature within the plate heat exchanger, in particular already during its manufacture.

[0009] In this case, thermocouple should be understood to mean a specific element that uses the so-called thermoelectric effect or Seebeck effect to measure temperature. Specifically, a thermocouple includes two conductors of different metals connected to each other at one end, for example, by welding. Thermoelectric effect or Seebeck effect refers to the voltage difference or potential difference (so-called thermoelectric voltage) that occurs due to the temperature gradient along the conductor. This voltage difference or potential difference is variable, specifically depending on the temperature difference along the conductor and also specifically for each conductor material. Therefore, when there is a temperature difference in two conductors made of different materials, different thermoelectric voltages are generated in the thermocouple. The connection point where the two conductors of the thermocouple are connected to each other at one end is conveniently exposed to the temperature to be measured, and is also referred to as a measuring point. At the other end (so-called comparison point) that is not connected to each other, the two conductors are specifically connected to a voltmeter. The temperature at the measuring point can be inferred from the voltage difference that can be determined at these ends or at the comparison point.

[0010] Alternatively (but in principle also in addition), at least one measuring resistor element in a capillary tube can be introduced into at least one spacer of the plate heat exchanger and used to monitor the temperature within the plate heat exchanger, specifically already during its manufacture. Measuring resistor elements are known per se and are also called temperature-dependent resistors or resistance thermometers. These measuring resistor elements are electronic components that use the temperature dependence of the resistance of an electrical conductor to measure temperature. Pure metals are typically used as the electrical conductor, but corrosion-resistant platinum is particularly preferred. A further advantage here is the practically linear relationship between temperature and resistance. Suitably designed platinum resistance thermometers can be used up to 1000°C. Standardized platinum measuring resistors such as Pt100 or Pt1000 are known, with nominal resistances R0 of 100 ohms and 1 kiloohm, respectively, at 0°C. In the simplest case, the voltage drop across a measuring resistor, caused by a constant measuring current, is measured, typically using a Wheatstone bridge in a two-conductor circuit. In order to avoid the influence of the measured values of the long leads of the sensor, three-conductor or four-conductor circuits are known. In this way, greater accuracy can be achieved, which is particularly independent of the material used for the connecting cable, while at the same time requiring correspondingly greater space.

[0011] Thermocouples and measuring resistor elements have excellent heat resistance and enable precise measurement recording even at high temperatures. Therefore, they are particularly suitable for use during the manufacturing process of plate heat exchangers, as they withstand the high temperatures encountered during material bonding and simultaneously allow precise recording of temperature values or measured temperature values. Specifically, thermocouples and measuring resistor elements are more heat-resistant than conventional optical waveguides. Consequently, conventional optical waveguides are generally not suitable for use during the manufacturing process of plate heat exchangers because they cannot withstand the high temperatures encountered. While it is possible to use high-temperature-resistant optical waveguides that can withstand such high temperatures, such high-temperature-resistant waveguides are very expensive. In contrast, thermocouples or measuring resistor elements make it possible to more effectively record or monitor temperatures not only during the operation of the plate heat exchanger but also during its manufacturing process.

[0012] Specifically, a plurality of thermocouples or measuring resistor elements are arranged for each capillary tube. Capillaries formed in this manner are hereinafter referred to as "thermocouple profile rods" or "measuring resistor element profile rods." These thermocouples or measuring resistor elements in the capillary tubes are conveniently arranged at an appropriate distance from one another to effectively record the temperature within the plate heat exchanger at corresponding points along the profile rod (that is, along the longitudinal extent of the capillary tube), specifically to record temperature differences, temperature distributions, or temperature fields. Furthermore, these capillaries are specifically arranged in a plurality of spacers, specifically in at least 10%, preferably at least 20%, 25%, 30%, 40%, or at least 50% of the spacers. Specifically, the spacers containing the capillaries are arranged at an appropriate distance from one another to effectively record the temperature within the plate heat exchanger, specifically to record temperature differences, temperature distributions, or temperature fields. This makes it possible to record temperature profiles in a plate heat exchanger even in a small installation space.

[0013] The specific type of thermocouple or measuring resistor element in the capillary tube can be selected specifically based on the specific characteristics of these types and, moreover, specifically depends on the conditions in the respective plate heat exchanger. The thermocouple type conveniently describes the combination of materials used for the two conductors in the respective thermocouple. For example, within the scope of the method according to the present invention, thermocouples of type K (having one NiCr conductor and the other Ni conductor) and / or type J (having Fe and CuNi conductors) and / or type L (having Fe and CuNi conductors) can be used. The measuring resistor element is preferably a Pt100 or Pt1000 measuring resistor, with a two-conductor circuit, a three-conductor circuit, or a four-conductor circuit being used, depending on the accuracy requirements and space limitations.

[0014] Preferably, during the material bonding process in the manufacture of the plate heat exchanger, a temperature value is recorded using at least one thermocouple or measuring resistor element of at least one capillary tube, and the material bonding process is monitored based on or in accordance with the recorded temperature value. Due to its excellent heat resistance, the at least one thermocouple or measuring resistor element allows for accurate temperature recording and monitoring within the plate heat exchanger during the manufacturing process of the plate heat exchanger or during the material bonding of the spacers and fins. Compared to optical waveguides, thermocouples or measuring resistor elements facilitate temperature recording and monitoring, even during the manufacturing process of the plate heat exchanger. Specifically, the material bonding process can be implemented or controlled in an open-loop and / or closed-loop manner based on the recorded temperature values. For example, the recorded temperature values can be used to monitor whether the spacers or fins have been heated to a sufficiently high level during the bonding process to achieve the desired bond strength, and / or whether temperature gradients have occurred during the bonding process that could compromise the durability or strength of the bond.

[0015] Advantageously, the spacers and fins are connected to each other in a material-bonded manner by a brazing process, preferably a vacuum brazing process. For example, for this purpose, a brazing material can be applied to the surface of the spacers, and the spacers and fins are then alternately stacked one on top of the other, with the side rods being arranged to close the two sides. Subsequently, the plate heat exchanger or its central body is brazed by heating in a furnace. In such brazing, an uneven temperature distribution may occur within the plate heat exchanger during heating or cooling. Due to the different thermal expansions and the resulting deformation differences, this may lead to gaps forming within the plate heat exchanger due to loose or not yet sufficiently firmly connected fins and spacers. It is therefore particularly preferred that a temperature value is recorded during the brazing process by means of at least one thermocouple or measuring resistor element in at least one capillary tube, and the brazing is monitored based on the recorded temperature value, and the brazing is also preferably controlled in an open-loop or closed-loop manner depending on the recorded temperature value. Thus, the effortless and precise recording of temperature values by means of thermocouples or measuring resistor elements allows the temperature distribution within the plate heat exchanger, and in particular also the temperature field or temperature differences, to be determined and monitored during brazing. In particular, the formation of gaps in the plate heat exchanger due to differential thermal expansion can be monitored and prevented in this way.

[0016] Advantageously, the at least one capillary tube is introduced into a groove in at least one spacer. The groove can be arranged inside the spacer in such a manner that the capillary tube is conveniently completely enclosed or covered by the spacer material. Specifically, during the manufacturing process of the plate heat exchanger, the groove can be introduced into the at least one spacer, for example by milling. Subsequently, the capillary tube can conveniently be introduced into the resulting groove. It is also conceivable that the at least one spacer already has the corresponding groove when obtained from the corresponding manufacturer, and that the capillary tube is simply introduced into the groove during the manufacturing process.

[0017] The at least one spacer with the capillary tube carrying the at least one thermocouple or measuring resistor element is preferably formed by a first spacer and a second spacer whose surfaces are adjacent to each other. Spacers (i.e., such as those used elsewhere in the manufacture of plate heat exchangers) can be used as spacers. Two spacers are then used instead of one, and the capillary tube is arranged therein.

[0018] Specifically, the groove is preferably introduced into at least one of the two adjacent surfaces of the first and second separators that face each other. The groove can be produced, for example, by milling. Alternatively, the groove can be introduced into only one separator, or specifically, into two adjacent surfaces of the separator in equal parts (two "half grooves").

[0019] Specifically, in this case, the capillaries are introduced into the grooves in such a way that they are completely encapsulated or covered by the material of the first and second separators. Similarly to the explanation above, the grooves can be introduced into the separators during the manufacturing process of the plate heat exchanger, for example by milling, or the separators can be readily obtained with grooves already present. In this case, the separators can also differ in another way from separators without capillaries and, for example, be only half the thickness of these separators. It is particularly advantageous to envision one of the separators of a plate heat exchanger that otherwise does not have capillaries inserted serving as the first and second separators, respectively. During the manufacturing process of the plate heat exchanger, in this case, half grooves can be specifically introduced into each of the two separators, for example by milling. Once one corresponding surface of the separator is placed on top of the other, the corresponding capillary can be introduced into the resulting complete groove, and the two separators can then be connected to each other in a material-bonded manner, for example by brazing or welding.

[0020] Preferably, outside the at least one septum, the at least one capillary is encapsulated in metal, formed as a metal capsule, or wrapped in a suitable metal. Specifically, the capillary thus has a first subregion or portion inside the septum and a second subregion or portion outside the septum. Alternatively or in addition, inside the at least one septum, the at least one capillary is preferably formed with a thin wall. Thus, specifically in its first subregion, the capillary is not encapsulated in metal.

[0021] Preferably, the at least one capillary protrudes from a process chamber, in particular a (vacuum) furnace for brazing, in which the material-bonding connection is carried out. In particular, due to the metal encapsulation in the second subregion outside the spacer, it is possible to prevent steam emissions from being released into the process chamber or furnace space during the connection process.

[0022] Of course, the manufacturing process for the plate heat exchanger can also include additional convenient steps before the plate heat exchanger can be put into operation. For example, the fins can be bounded on both sides by so-called side bars, which are materially bonded to adjacent spacers, for example, by brazing. This conveniently creates a plurality of parallel heat exchange channels through which two fluids or media can pass for indirect heat exchange during normal operation of the plate heat exchanger. Particularly advantageously, the at least one capillary tube with the at least one thermocouple or measuring resistor element is not removed from the at least one spacer at a later stage in the manufacturing process, or even after the manufacturing process has been fully carried out. Consequently, the at least one capillary tube with the at least one thermocouple or measuring resistor element remains in the plate heat exchanger even after the manufacturing process and can be conveniently used during normal operation of the plate heat exchanger.

[0023] If a capillary tube with at least one thermocouple or measuring resistor element has been placed in the groove during the brazing process, it will be encapsulated by the brazing material during the brazing process and can no longer be removed (for example, for repairs, etc.). To avoid this, a larger capillary tube, such as stainless steel or some other material with a melting point much higher than aluminum, must be placed in the groove. The interior space of this larger capillary tube remains free of brazing material so that the temperature measuring device with the measuring element can be inserted and removed again. The same procedure is also necessary if the temperature measuring device is not intended to be in the plate heat exchanger during the brazing process. If there is only one groove at the time, it is filled with brazing material. Therefore, here too, brazing needs to be performed to include the formation of a larger capillary tube, which then reserves space for the temperature measuring device. For example, a heat-stable stainless steel tube with the smallest possible wall thickness (for example 0.2 mm) can be used for this purpose to ensure the required cross-section.

[0024] A particularly preferred embodiment of the present invention relates to a method for operating a plate heat exchanger manufactured according to a preferred embodiment of the method of the present invention. During this operation, a first fluid and a second fluid are passed through the plate heat exchanger, specifically through a heat exchange channel formed by interconnected fins and spacers, which is laterally delimited by side bars. Advantageously, the two fluids are caused to pass through each other in countercurrent, and in particular, indirect heat exchange can be performed. During this operation of the plate heat exchanger, temperature values are particularly advantageously recorded using at least one thermocouple or measuring resistor element in the at least one capillary tube. This makes it possible to perform temperature recording during the material bonding process of the fins and spacers, as well as during normal operation of the plate heat exchanger, using the same temperature measuring device in the form of at least one thermocouple or measuring resistor element (that is, specifically one or more of the thermocouple or measuring resistor element profile bars defined above). Thermocouples or measuring resistor elements used during the manufacturing process for monitoring the material bonding process, preferably brazing or vacuum brazing, can therefore also continue to be used during normal operation of the plate heat exchanger to record temperature values, in particular to determine temperature differences or temperature distributions or temperature fields within the plate heat exchanger. In particular, there is no need to provide additional temperature measuring devices for normal operation, which saves costs and effort.

[0025] According to a preferred embodiment, the operation of the plate heat exchanger is controlled in an open-loop and / or closed-loop manner based on the temperature values recorded during operation of the plate heat exchanger. Specifically, the currently recorded temperature values can thus be used to ensure efficient and optimal operation of the plate heat exchanger. Furthermore, the recorded temperature values are specifically used to optimize the operation or operating mode of the plate heat exchanger, which advantageously also makes it possible to extend the remaining life of the plate heat exchanger.

[0026] Advantageously, the lifetime consumption and / or remaining lifetime of the plate heat exchanger is determined based on temperature values recorded during operation of the plate heat exchanger. To this end, the currently recorded temperature value is evaluated and, for example, compared with stored data or temperature values recorded at an earlier time, and / or used as input data for a theoretical model or simulation of the plate heat exchanger. Temperature values within the plate heat exchanger can be recorded using thermocouples or measuring resistor elements arranged within the plate heat exchanger, allowing for particularly efficient and effortless lifetime monitoring. Specifically, the temperature values can be used to deduce thermal or mechanical stresses within the plate heat exchanger, thereby conveniently determining the lifetime consumption and / or remaining lifetime of the plate heat exchanger. Furthermore, the currently recorded temperature value can also be conveniently archived and stored, for example, in a control unit, for comparison with temperature values recorded at a later time and, therefore, for future determination of the lifetime consumption and / or remaining lifetime.

[0027] The operating history of the plate heat exchanger is preferably determined based on temperature values recorded during operation of the plate heat exchanger. In this context, the operating history should be understood to mean specific processes, changes in the process, or environment in the plate heat exchanger that affect the lifespan or remaining lifespan of the plate heat exchanger. Specifically, the operating history of the plate heat exchanger relates to applied load changes, that is, specific processes during which mechanical stress changes occur in the plate heat exchanger. In particular, the number of applied load changes and / or the rate at which individual load changes are applied are determined based on the temperature values recorded during operation of the plate heat exchanger as the operating history.

[0028] The plate heat exchanger according to the present invention has a plurality of spacers and a plurality of fins, wherein a fin of the plurality of fins is respectively arranged between two adjacent spacers of the plurality of spacers, and at least one capillary tube having at least one thermocouple and / or measuring resistor element is introduced into at least one of the spacers. The advantages and preferred configurations of the method according to the present invention and the plate heat exchanger according to the present invention are apparent from this description in a similar manner.

[0029] In the case of the plate heat exchanger according to the present invention, the at least one spacer is preferably formed by a first spacer and a second spacer whose surfaces are adjacent to each other, a groove has been introduced into at least one of the two adjacent surfaces of the first spacer and the second spacer and the at least one capillary is arranged in the groove.

[0030] The plate heat exchanger according to the invention is produced in particular according to a preferred embodiment of the method according to the invention.

[0031] Furthermore, the plate heat exchanger is preferably designed for operation according to the preferred embodiments of the method according to the invention as described above. Specifically, a control unit can be provided for this purpose, for example in the form of a stored program controller (SPC), which is designed to be specifically programmed to implement the preferred embodiments of the method according to the invention. Specifically, the control unit can receive and conveniently store and / or evaluate temperature values recorded during operation of the plate heat exchanger by means of at least one thermocouple or measuring resistor element of the at least one capillary tube, in particular in order to control the plate heat exchanger accordingly in an open-loop and / or closed-loop manner and / or to determine the lifetime consumption or remaining lifetime and / or to determine the operating history.

[0032] Further advantages and configurations of the invention will emerge from the description and the accompanying drawings.

[0033] Further possible configurations of the invention also include combinations of features described above or below with respect to exemplary embodiments not explicitly specified. In this case, a person skilled in the art will also be able to add the various aspects described herein as improvements or supplements to the corresponding basic embodiments of the plate heat exchanger according to the invention or the method according to the invention.

[0034] The invention is schematically illustrated in the drawings on the basis of exemplary embodiments and will be described hereinafter with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 schematically and perspectively shows a plate heat exchanger according to the present invention before installing the inlet and outlet attachments ( Figure 1A ) and after ( Figure 1B ) of the preferred construction, these accessories have been manufactured and can be operated according to the preferred embodiment of the method of the present invention.

[0036] Figure 2 Details of a preferred construction of a plate heat exchanger according to the invention are shown schematically.

[0037] Figure 3 A preferred embodiment of the method according to the invention is schematically shown in a block diagram.

[0038] One or more embodiments of the present invention

[0039] In FIG. 1 , a preferred construction of a plate heat exchanger according to the invention is shown schematically and in perspective and is denoted by 1 .

[0040] according to Figure 1A The plate heat exchanger 1 has a cubic central body 8, which has a length of, for example, several meters and a width and height of, for example, about one or several meters. The central body 8 is essentially an arrangement of alternating spacers 20 and fins 11, 12. Thus, the central body 8 of the plate heat exchanger 1 has a plurality of spacers and a plurality of fins, each of which is arranged between two adjacent spacers. Both the spacers and the fins can be made of, for example, aluminum. The fins 11, 12 are closed on their sides by side bars 4, which can also be made of aluminum, so that side walls are formed due to the stacking structure with the spacers 20. The outer fins of the central body 8 (here 11) are closed by a cover 5 (outer sheet), which is parallel to the fins and spacers and is usually also made of aluminum.

[0041] To manufacture the plate heat exchanger 1, spacers 20, side bars 4 and fins (only fins 11 and 12 are shown here), which are usually brazed clad, are placed one on top of the other in a stacked manner to form the central body 8 shown here, which is then brazed in a brazing furnace under vacuum. Figure 1BAs shown, the inlet and outlet fittings 6, 6a required for the heat exchange fluid to enter and exit are installed.

[0042] exist Figure 1B , the accessories 6 and 6a are visible on the top of the central body 8, on its sides and under the central body 8. The accessories 6 and 6a located under the central body 8 and on the side facing away from the shown side are partially hidden.

[0043] Fluids or process streams can be fed into the plate heat exchanger 1 and removed from the plate heat exchanger again via the nozzles 7. The appendages 6 and 6a serve to distribute the fluid introduced via the nozzles 7 and to collect and concentrate the fluid to be removed from the plate heat exchanger 1, this distribution and collection being carried out by the distributor fins 3 which move to and from the heat exchanger fins 11, 12 (see Figure 1A ). Then, in the plate heat exchanger 1, the various flows of the fluid exchange heat energy.

[0044] The plate heat exchanger 1 shown in Figure 1 is designed to allow fluid streams to pass through each other in separate channels to exchange heat. Some streams can pass through each other in countercurrent, while other streams can pass through in crossflow or simultaneously.

[0045] At least one capillary tube having at least one thermocouple or measuring resistor element has been introduced into at least one septum 20 of the plurality of septa, as described below with reference to Figure 2 As explained, the figure shows schematically and in perspective a detail of a plate heat exchanger 1 .

[0046] from Figure 2As can be seen in the figure, the fins 11 and 12 are arranged along the spacer 20. The fins 11 and 12 are only shown very schematically because the paths followed by these fins on the lower surface of the detail shown here are shown. The channel formed by the fins 11 and 12 extends parallel to the portion 31, which will be described below. The spacer 20 includes two spacers 21 and 22, into which grooves 23 or 24 are introduced respectively. In these (half) grooves 23 and 24, the capillary 30 has been introduced into the spacer 20 in a manner that the capillary 30 is completely encapsulated or covered by the material of the first spacer 21 and the second spacer 22. It is also possible to introduce only one groove into only one of the spacers 21, 22 and then insert the capillary therein. Conventional spacers or separators can be used as, for example, spacers 21, 22. Specifically, in this case, the capillary 30 has a first portion 31 inside the spacer 20 and a second portion 32 outside the spacer 20. Arranged in the capillary tube 30 in a first section 31 inside the spacer 20 are a plurality of mutually spaced-apart thermocouples or measuring resistor elements 40 (“thermocouple or measuring resistor element profile rods”), by means of which temperature values can be recorded along the longitudinal direction of the capillary tube 30 within the plate heat exchanger 1. The capillary tube 30 is designed in particular to have a thin wall in the first section 31 or as a thin stainless steel tube, and is encapsulated in metal (that is, by metal sheathing) or is formed as a thicker tube in the second section 32.

[0047] On the outside of the spacer 20, the capillary tube 30 extends to a conversion point 50, which can be connected to a computing unit 60, such as a control unit, via wiring 51. Specifically, the computing unit 60 can receive and evaluate the temperature values recorded by the thermocouple or measuring resistor element 40 and, for example, send the resulting data from there to the cloud via a transmitter for further processing. The conversion point 50 can, for example, take the form of an interface between the process chamber in which the plate heat exchanger 1 is located and the outside world, so that the computing unit 60 does not necessarily need to be arranged in the process chamber. For example, the process chamber can be a furnace or brazing furnace during the manufacturing process of the plate heat exchanger 1, or a cold box during normal operation of the plate heat exchanger 1.

[0048] If the measuring element is a thermocouple, the wiring must ideally continue in region 51 with the same material as in region 32. Otherwise, unit 60 will not be able to measure the thermoelectric voltage correctly unless the temperature at transition point 50 is also measured and the thermoelectric voltage corrected accordingly. Such wiring problems can be avoided if a measuring resistor element is used.

[0049] The plate heat exchanger 1 is manufactured and operated in particular according to a preferred embodiment of the method of the invention, as hereinafter referred to Figure 3 Explained, wherein a preferred embodiment of the method according to the invention is schematically shown in a block diagram.

[0050] In this case, the manufacturing process of the plate heat exchanger 1 is indicated by 100. During the manufacturing process 100, first, in step 101, a plurality of spacers and a plurality of fins are provided.

[0051] The spacers correspond to e.g. Figure 2 In step 102, grooves are milled in some of the spacers in order to obtain, for example, Figure 2 The separators 21 and 22 are shown. For example, grooves can be introduced into 25% of the plurality of separators.

[0052] In step 103, a capillary 30 is introduced in each case between the two grooved sheets 21, 22 provided in step 102, so that a separator sheet 20 with capillaries 30 is obtained in each case, such as Figure 2 Thus, in this example, the thickness of the septum 20 with the capillary tube 30 is twice the thickness of the septum without the capillary tube, because the septum 20 with the capillary tube 30 is each made from two such septums without the capillary tube.

[0053] In step 104, brazing material is applied to the surfaces of the spacers in a processing chamber (e.g., a furnace), and the spacers and fins are then stacked alternately one on top of the other. For example, in this case, every four spacers can be one spacer 20 with a capillary 30, so that adjacent spacers (separators) must be connected by brazing. After stacking, in step 105, the individual capillaries 30 are each connected to the computing unit via a switching point, and in step 106, the spacers and fins are connected to each other in a material-bonded manner by brazing in the furnace.

[0054] During brazing, the temperature values within the plate heat exchanger are recorded in step 107 by means of a thermocouple in the capillary tube 30 or a measuring resistor element 40 and transmitted to a computing unit. In step 108, the further brazing process is monitored based on or in accordance with the recorded temperature values. In particular, in this case, it is advantageous to monitor the temperature distribution in the plate heat exchanger in order to prevent gaps from forming within the plate heat exchanger due to differential thermal expansion during the brazing operation and due to deformation differences caused by loose or insufficiently securely connected spacers and fins.

[0055] When the fins and spacers or separators have been successfully connected to each other, in step 109, the attachments 6, 6a, the nozzles 7 and the cover are mounted on the plate heat exchanger 1. After the plate heat exchanger 1 has been successfully manufactured, the capillary tube 30 can be separated from the computing unit 60 in step 110.

[0056] Even after the manufacturing process has been successfully performed, the capillary tube 30 remains within the plate heat exchanger 1 and the thermocouple or measuring resistor element 40 can also be used to record temperature values during normal operation, as described below.

[0057] The normal operation of the plate heat exchanger 1 is Figure 3 Indicated by 200. In step 201, the capillary tube 30 is again connected to a calculation unit, for example to a control unit. In step 202, the two fluids are passed through the plate heat exchanger 1 in countercurrent in order to perform indirect heat exchange.

[0058] During this operation of the plate heat exchanger, temperature values are recorded in step 203 by means of a thermocouple in the capillary tube 30 or a measuring resistor element 40. In step 204, the operation of the plate heat exchanger 1 is controlled in an open-loop or closed-loop manner based on these recorded temperature values. Specifically, in this case, the operation can be optimized in order to extend the remaining service life of the plate heat exchanger 1.

[0059] Furthermore, in step 205, the life consumption or remaining life of the plate heat exchanger 1 is determined based on the recorded temperature value. For example, the temperature value can be used to determine the thermal stress or mechanical stress in the plate heat exchanger 1, thereby determining the life consumption and remaining life of the plate heat exchanger 1.

[0060] In step 206 , the recorded temperature values are advantageously archived in the computing unit so as to be available for comparison with temperature values recorded at a later time.

[0061] The present invention thus makes it possible to carry out temperature recording during the manufacturing process of the plate heat exchanger 1, during the brazing of the fins and spacers, and also during normal operation of the plate heat exchanger 1, using the same temperature measuring device in the form of a thermocouple or a measuring resistor element 40 in the capillary tube 30. The thermocouple or measuring resistor element 40 used for monitoring the brazing during the manufacturing process can also continue to be used in normal operation.

[0062] Reference Signs List

[0063] 1 Plate heat exchanger

[0064] 3 Distributor fins

[0065] 4 Sidebars

[0066] 5 Covering

[0067] 6 Attachments

[0068] 6a Attachments

[0069] 7 Nozzles

[0070] 8 The main body of the center

[0071] 11 fins

[0072] 12 fins

[0073] 20 spacers

[0074] 21 separator

[0075] 22 separators

[0076] 23 Grooves

[0077] 24 grooves

[0078] 30 capillaries

[0079] 31 First part of the capillary

[0080] 32 Second part of the capillary

[0081] 40 Thermocouple or measuring resistor elements

[0082] 50 conversion points

[0083] Line 51

[0084] 60 computing units

[0085] 100 Manufacturing Process

[0086] 101 to 110 Methods and Steps

[0087] 200 General Operations

[0088] 201 to 206 Method Steps

Claims

1. A plate heat exchanger (1) comprising a plurality of spacers (20) and a plurality of fins (11, 12), wherein the fins of the plurality of fins are respectively arranged between two adjacent spacers of the plurality of spacers, and at least one capillary tube (30) having at least one measuring resistor element (40) is arranged in at least one spacer (20) of the plurality of spacers, wherein a plurality of measuring resistor elements are arranged in each capillary tube, the measuring resistor element being an electronic component for measuring temperature using the temperature dependence of the resistance of an electrical conductor.

2. The plate heat exchanger (1) according to claim 1, wherein the at least one spacer (20) is formed by a first spacer (21) and a second spacer (22) whose surfaces are adjacent to each other, a groove (23, 24) has been introduced into at least one of the two adjacent surfaces of the first spacer (21) and the second spacer (22), and the at least one capillary tube (30) is arranged in the groove (23, 24).

3. The plate heat exchanger (1) according to claim 1 or 2, wherein the spacers (20) and the fins (11, 12) are respectively connected to each other in a material-bonded manner (106) by a vacuum brazing process.

4. The plate heat exchanger (1) according to claim 1 or 2, wherein the at least one capillary tube (30) is formed with a thin wall in a first portion (31) located inside the at least one spacer (20), and / or wherein the at least one capillary tube (30) is enclosed in metal in a second portion (32) located outside the at least one spacer (20).

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