Method for producing plate heat exchanger, and plate heat exchanger with thermocouples or measuring resistors

Abstract

To provide a method for producing a plate heat exchanger which has multiple parting sheets and multiple fins.SOLUTION: Each fin is arranged between two neighboring parting sheets, where at least one capillary (30) with at least one thermocouple and / or measuring resistor element (40) is introduced into at least one parting sheet (20), and in each case a parting plate of the multiple parting plates and a fin of the multiple fins are alternately arranged and are connected to one another by material bonding. The invention also concerns a plate heat exchanger (1) produced by the method.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a plate heat exchanger, and to a plate heat exchanger having a plurality of divided sheets and a plurality of fins, each of which is disposed between two adjacent divided sheets. [Background technology]

[0002] A plate heat exchanger has a number of dividing sheets or separator plates arranged parallel to one another and a number of fins arranged between every two adjacent dividing sheets, so that a number of parallel channels through which a medium can pass between the adjacent plates are formed. On both sides, the fins are separated by so-called side bars brazed to the adjacent plates. In this way, a number of parallel heat exchange passages are formed, so that the medium can be passed, for example, in the opposite direction to each other, in order to perform indirect heat exchange.

[0003] Thermal stresses as a result of the different thermal expansions caused by the differential temperature difference can mechanically deteriorate the integrity of the seals between the heat exchange passages to such an extent that the plate heat exchanger leaks with respect to its surroundings. To analyze the temperature field, such a plate heat exchanger can be equipped with temperature measuring devices, for example, on the surface of its skin. However, the temperature on the skin only provides local values, which can be used to infer the temperature inside the plate heat exchanger by making assumptions. However, since the measurements are made on the skin, these temperature measurements can be affected by environmental influences.

[0004] WO 2014 / 056587 A1, for example, describes a plate heat exchanger with optical waveguides for temperature measurement, which in this case are arranged in open grooves provided either in the fins or in the dividing sheets of the plate heat exchanger.

[0005] It is desirable to improve the possibilities for temperature measurement in plate heat exchangers.

[0006] Disclosure of the Invention Against this background, the invention proposes a method for manufacturing a plate heat exchanger and a plate heat exchanger having a number of separate sheets and a number of fins, each of which is arranged between two adjacent separate sheets, with the features of the independent claims. Advantageous configurations are the subject of the dependent claims and the following description.

[0007] Within the scope of the method for manufacturing a plate heat exchanger, at least one capillary with at least one thermocouple and / or one measuring resistance element is introduced into at least one of the plurality of divided sheets, the divided sheets of the plurality of divided sheets and the fins of the plurality of fins are respectively arranged alternately and connected to one another by a material joint, so that the fins are each arranged between two divided sheets running parallel to one another.

[0008] The invention is based on the realized idea of ​​introducing at least one thermocouple in a capillary and / or one measuring resistance element into at least one dividing sheet of a plate heat exchanger and using it already during the manufacture of the plate heat exchanger to monitor the temperature in the plate heat exchanger.

[0009] In this context, a thermocouple should be understood as meaning in particular an element that uses the so-called thermoelectric or Seebeck effect to measure temperature. In particular, a thermocouple comprises two electrical conductors of different metals that are connected to one another at one end, for example by a welded connection. The thermoelectric or Seebeck effect refers to the generation of a voltage or potential difference (so-called thermoelectric voltage) due to the temperature gradient along the electrical conductor. This voltage or potential difference varies in particular depending on the temperature difference along the conductor and in particular for each conductive material. As a result, if there is a temperature difference between two conductors made of different materials, separate thermoelectric voltages are generated in the thermocouple. The connection point, where the two conductors of the thermocouple are connected to one another at one of their ends, is conveniently exposed to the temperature to be measured and is also called the measurement point. At the other end, which is not connected to one another (the so-called comparison point), the two conductors are in particular connected to a voltmeter. The temperature at the measurement point can be deduced from the voltage difference that is ascertainable at these ends or at this comparison point.

[0010] Alternatively (but in principle additionally), at least one measuring resistive element in a capillary tube can be introduced into at least one dividing sheet of the plate heat exchanger and used to monitor the temperature in the plate heat exchanger, in particular already during its manufacture. Measuring resistive elements are known per se and are also called temperature-dependent resistors or resistance thermometers. These are electrical components that use the temperature dependence of the electrical resistance of an electrical conductor to measure the temperature. Pure metals, in particular corrosion-resistant platinum, are generally used as electrical conductors. The advantage here is also the substantially linear relationship between temperature and resistance. Platinum resistance thermometers of suitable construction can be used up to 1000 ° C. There are known standardized platinum measuring resistors such as Pt100 or Pt1000, in which the nominal resistance R0 at 0 ° C is 100 ohms and 1 kiloohm, respectively. In the resistance measurement, in the simplest case, the voltage drop across a measuring resistor through which a constant measuring current flows is measured, for this purpose a Wheatstone bridge is usually used in a two-conductor circuit. To avoid the influence of long conductors to the sensor on the measured values, three- or four-conductor circuits are known. In this way, a much higher precision can be achieved, especially independent of the material used for the connecting cable, but at the same time there are correspondingly larger space requirements.

[0011] Thermocouples and measuring resistor elements have high heat resistance and allow accurate measurement values ​​to be recorded even at high temperatures. Therefore, thermocouples and measuring resistor elements are particularly suitable for use already during the manufacturing process of plate heat exchangers, since they can withstand the high temperatures that occur during material bonding and at the same time allow accurate recording of temperature values ​​or measured temperature values. In particular, thermocouples and measuring resistor elements are much more heat resistant than conventional optical waveguides. Conventional optical waveguides therefore usually cannot be used during the manufacturing process of plate heat exchangers, because the optical waveguides cannot withstand the high temperatures that occur thereby. It is possible to use high-temperature heat-resistant optical waveguides that can be exposed to such high temperatures, but such high-temperature heat-resistant optical waveguides are very costly. In contrast to this, the use of thermocouples or measuring resistor elements can allow temperature recording or temperature monitoring in a much more favorable way, not only during operation but also during the manufacturing process of the plate heat exchanger.

[0012] In particular, a number of thermocouples or measuring resistor elements are arranged per capillary. The capillaries thus formed are hereinafter called "thermocouple profile bar" or "measuring resistor element profile bar". The thermocouples or measuring resistor elements in these capillaries are advantageously arranged at a suitable distance from each other in order to be able to effectively record the temperature in the plate heat exchanger at corresponding points along the profile bar, i.e. along the longitudinal extent of the capillaries, in particular to be able to record the temperature difference or temperature distribution or temperature field. Moreover, such capillaries are specifically arranged on at least 10% of the dividing sheets, preferably at least 20%, 25%, 30%, 40% or at least 50% of the dividing sheets. In particular, the dividing sheets with the capillaries are arranged at a suitable distance from each other in order to effectively record the temperature in the plate heat exchanger, more particularly to be able to record the temperature difference or temperature distribution or temperature field. In particular, in this way it may be possible to record the temperature profile in the plate heat exchanger in a small installation space.

[0013] The specific types of thermocouples or measuring resistive elements in the capillaries can be selected in particular according to the specific characteristics of these types and also in particular according to the conditions of the respective plate heat exchanger. The type of thermocouple conveniently describes the combination of materials of the two conductors used in the respective thermocouple. For example, within the scope of the present method, it is possible to use type K thermocouples (one conductor is NiCr and the other Ni) and / or type J thermocouples (with a conductor made of Fe and a conductor made of CuNi) and / or type L thermocouples (with a conductor made of Fe and a conductor made of CuNi). The measuring resistive elements are preferably Pt100 or Pt1000 measuring resistors, with a 2-, 3- or 4-conductor circuit used according to the accuracy requirements and space limitations.

[0014] Preferably, temperature values ​​are recorded during the material bonding in the manufacture of the plate heat exchanger with at least one thermocouple or measuring resistor element of at least one capillary, and the material bonding is monitored on the basis of or in response to the recorded temperature values. Due to its excellent heat resistance, with at least one thermocouple or measuring resistor element, the temperature in the plate heat exchanger can be accurately recorded and monitored during its manufacturing process or during the material bonding of the dividing sheet and the fin. In contrast to optical waveguides, the thermocouple or measuring resistor element allows for easy temperature recording and temperature monitoring even during the manufacturing process of the plate heat exchanger. In particular, the material bonding process can be performed or controlled in an open loop and / or in a closed loop in response to the recorded temperature values. For example, it can be monitored in response to the recorded temperature values ​​whether the dividing sheet or the fin is heated to a sufficiently high level in the course of the bonding process to achieve the desired bond strength and / or whether temperature gradients occur during the bonding process that may deteriorate the durability or strength of the bond.

[0015] The dividing sheets and the fins are expediently connected to one another with a material joint by a brazing process, preferably by a vacuum brazing process. For example, for this purpose brazing can be applied to the surfaces of the dividing sheets, after which the dividing sheets and the fins can be stacked one on top of the other, with the side bars arranged to close the sides. The plate heat exchanger or its central body is then brazed by heating in a furnace. With such brazing, an uneven temperature distribution can be generated in the plate heat exchanger during heating or cooling. Due to differences in thermal expansion and the resulting deformation differences, gaps can form in the plate heat exchanger, since the fins and the dividing sheets are loosely or not yet firmly connected enough. Therefore, particularly preferably, the temperature values ​​are recorded during the brazing process by means of at least one thermocouple or measuring resistance element in at least one capillary, and the brazing is monitored on the basis of the recorded temperature values ​​and is also preferably controlled in an open or closed loop depending on the recorded temperature values. Thus, by simply and precisely recording the temperature values ​​using thermocouples or measuring resistor elements, it is possible to determine and monitor the temperature distribution, and in particular the temperature field or temperature difference, in the plate heat exchanger during brazing. In particular, in this way the formation of gaps in the plate heat exchanger due to differences in thermal expansion can be monitored and prevented.

[0016] Advantageously, at least one capillary is introduced into the groove of the at least one divided sheet. This groove may in particular be provided in the interior of the divided sheet such that the capillary is advantageously completely surrounded or covered by the material of the divided sheet. In particular, the groove may for example be introduced into the at least one divided sheet during the manufacturing process of the plate heat exchanger, for example by milling. The capillary may then be advantageously introduced into the formed groove. It is likewise conceivable that when the at least one divided sheet is obtained from a corresponding manufacturer, this sheet already has a corresponding groove, and only the capillary is introduced into the groove during the manufacturing process.

[0017] Preferably, at least one divided sheet with a capillary with at least one thermocouple or measuring resistance element is formed from a first partial sheet and a second partial sheet with mutually adjacent surfaces. Other divided sheets, i.e. divided sheets as used elsewhere in the manufacture of plate heat exchangers, can in particular be used here as partial sheets. Then, two divided sheets instead of one are used and the capillary is arranged therein.

[0018] In particular, the grooves are preferably introduced into at least one of the two adjacent, facing surfaces of the first and second partial sheets. The grooves can be formed, for example, by milling. The grooves are either introduced into only one partial sheet, or in particular into both surfaces of the adjacent partial sheets in equal portions (two "half grooves")

[0019] Specifically, in this case, the capillaries are introduced into the grooves so that they are completely surrounded or covered by the material of the first and second partial sheets. Analogously to the above explanation, the grooves can be introduced into the partial sheets, in particular during the manufacturing process of the plate heat exchanger, for example by milling, or it is also possible to obtain partial sheets that are already provided with grooves. In this case, the partial sheets can on the one hand differ from the partial sheets in which the capillaries are not introduced, for example only having half the thickness of these partial sheets. It is particularly preferable to envisage that one of the partial sheets of the plate heat exchanger in which no capillaries are inserted is used as the first and second partial sheet. In the manufacturing process of the plate heat exchanger, half grooves can be introduced into two such partial sheets, in this case specifically by milling, for example. When the corresponding surfaces of the partial sheets are placed one on top of the other, the corresponding capillaries can be introduced into the finished grooves thus formed, and then the two partial sheets can be joined to one another with a material joint, for example by brazing or welding.

[0020] Preferably, at least one capillary is, outside at least one dividing sheet, encapsulated in metal, formed as a metal capsule or enveloped in a suitable metal. In particular, the capillary thus has a first sub-region or part inside the dividing sheet and a second sub-region or part outside the dividing sheet. Alternatively or additionally, at least one capillary is, inside at least one dividing sheet, preferably formed with a thin wall. Thus, in particular in its first sub-region, the capillary is not encapsulated in metal.

[0021] Preferably, at least one capillary is led out of the process chamber in which the material bonding is carried out, in particular from a (vacuum) furnace for brazing, in particular a metal encapsulation in said second sub-region outside the dividing sheet makes it possible to prevent vapor emissions from being discharged into the process chamber or furnace space during the bonding process.

[0022] It goes without saying that the manufacturing process of the plate heat exchanger may include further advantageous steps before putting the plate heat exchanger into operation, for example the fins may be separated on both sides by so-called side bars which are materially joined, for example by brazing, to the adjacent dividing sheets. A number of parallel heat exchange passages are thus advantageously manufactured, 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 with the at least one thermocouple or measuring resistance element is not removed from the at least one dividing sheet during a later stage of the manufacturing process or even after the manufacturing process has been completely carried out. Thus, the at least one capillary with the at least one thermocouple or measuring resistance element remains in the plate heat exchanger even after the manufacturing process and can be advantageously used during normal operation of the plate heat exchanger.

[0023] If a capillary with at least one thermocouple or measuring resistance element is placed in the groove during the brazing process, this capillary will be surrounded by the brazing during the brazing process and will not be able to be removed afterwards (e.g. in case of repairs, etc.). To avoid this, a larger capillary, for example made of stainless steel or of some other material with a much higher melting point than aluminum, would have to be placed in the groove. The internal space of this larger capillary will remain free of brazing so that a temperature measuring device with a measuring element can be inserted and removed again. The same procedure is also necessary if no temperature measuring device is intended to be in the plate heat exchanger during the brazing process. Any empty grooves are filled with brazing. In this case too, the brazing will have to consequently include the creation of a larger capillary, so that free space for the temperature measuring device is preserved. To ensure the required cross-sectional area, thermally stable stainless steel tubes with the smallest possible wall thickness (e.g. 0.2 mm) may be used.

[0024] A particularly preferred embodiment of the present invention relates to a method for operating a plate heat exchanger manufactured according to the preferred embodiment of the above-mentioned method according to the present invention. In the course of this operation, a first fluid and a second fluid pass through the plate heat exchanger, in particular through the heat exchange passages formed by the interconnected fins and the dividing sheets, which are separated on both sides by side bars. Advantageously, these two fluids are arranged to pass in opposite directions, in particular so that an indirect heat exchange can take place. During this operation of the plate heat exchanger, particularly advantageous temperature values ​​are recorded with the aid of at least one thermocouple or measuring resistor element in at least one capillary. In this way, it becomes possible to carry out temperature recordings during the material bonding process of the fins and the dividing sheets, as well as during normal operation of the plate heat exchanger, with the aid of a similar temperature measuring device in the form of at least one thermocouple or measuring resistor element, i.e. in particular using one or more of the thermocouple or measuring resistor element profile bars defined above. As a result, the thermocouples or measuring resistance elements used during the manufacturing process to monitor the material bonding process (preferably brazing or vacuum brazing) can continue to be used in the normal operation of the plate heat exchanger to record temperature values, in particular to determine the temperature difference or the temperature distribution or temperature field in the plate heat exchanger, in particular, as a result, there is no need to provide additional temperature measuring devices for normal operation, which can save costs and efforts.

[0025] According to a preferred embodiment, the operation of the plate heat exchanger is controlled in an open loop and / or a closed loop depending on the temperature values ​​recorded during the operation of the plate heat exchanger. In particular, the currently recorded temperature values ​​can be used to enable an effective and best possible operation of the plate heat exchanger. Furthermore, the recorded temperature values ​​can in particular be used to carry out an optimization of the operation or the operating mode of the plate heat exchanger, which can advantageously also extend the remaining life of the plate heat exchanger.

[0026] Advantageously, the life consumption and / or remaining life of the plate heat exchanger is determined as a function of temperature values ​​recorded during the operation of the plate heat exchanger. For this purpose, the currently recorded temperature values ​​can be evaluated and in this case compared, for example, with stored data or previously recorded temperature values ​​and / or can be used, for example, as input data for a theoretical model or simulation of the plate heat exchanger. The life can be monitored particularly effectively and simply, since the temperature values ​​inside the plate heat exchanger can be recorded by means of thermocouples or measuring resistance elements arranged in the plate heat exchanger. In particular, the temperature values ​​can be used to obtain the thermal or mechanical stresses in the plate heat exchanger, and accordingly the life consumption and / or remaining life of the plate heat exchanger can be advantageously determined. Furthermore, the currently recorded temperature values ​​can also be advantageously stored, for example stored in a control unit, in order to be used for comparison with later recorded temperature values ​​and, as a result, for future determination of the life consumption and / or remaining life.

[0027] Preferably, the operating history of the plate heat exchanger is determined according to the temperature values ​​recorded during the operation of the plate heat exchanger. In this context, operating history should be understood as meaning a specific process, process change, or situation change of the plate heat exchanger that affects the life consumption or remaining life of the plate heat exchanger. In particular, the operating history of the plate heat exchanger relates to the load changes that are carried out, i.e., in particular to the processes in which the mechanical stresses occurring in the plate heat exchanger change in the process. In particular, the number of load changes to be carried out and / or the speed at which each load change is carried out are determined according to the temperature values ​​recorded as the operating history during the operation of the plate heat exchanger.

[0028] The plate heat exchanger according to the invention has a plurality of dividing sheets and a plurality of fins, each of which is arranged between two adjacent dividing sheets of the plurality of dividing sheets, and at least one capillary tube with at least one thermocouple and / or measuring resistance element is introduced into at least one of the dividing sheets. Advantages and preferred configurations of the method according to the invention and the plate heat exchanger according to the invention are likewise evident from the present description.

[0029] In the case of a plate heat exchanger according to the invention, at least one dividing sheet is preferably formed from a first partial sheet and a second partial sheet having mutually adjacent surfaces, a groove is introduced into at least one of the two adjacent surfaces of the first partial sheet and the second partial sheet, and at least one capillary is arranged in the groove.

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

[0031] Furthermore, the plate heat exchanger is preferably designed to be operated according to the preferred embodiment of the method according to the invention described above. In particular, a control unit may be provided for this purpose, for example in the form of a stored program controller (SPC), designed to execute the preferred embodiment of the method according to the invention, in particular with regard to programming. In particular, this control unit can receive and conveniently store and / or evaluate temperature values ​​recorded during operation of the plate heat exchanger, in particular by means of at least one thermocouple or measuring resistor element of at least one capillary, in order to control the plate heat exchanger accordingly in an open loop and / or in a closed loop and / or to determine the life consumption or remaining life and / or to determine the operating history.

[0032] Further advantages and configurations of the invention will become apparent from the specification and the accompanying drawings.

[0033] Further possible configurations of the present invention also include combinations of the features described above or below with respect to exemplary embodiments not explicitly specified, in which case the skilled person will also add individual aspects described herein as improvements or additions to the respective basic embodiment of the plate heat exchanger according to the invention or the method according to the invention.

[0034] The invention is illustrated diagrammatically in the drawings on the basis of an exemplary embodiment and is explained below with reference to the drawings. [Brief description of the drawings]

[0035] [Figure 1A] 1 shows diagrammatically and in perspective a preferred configuration of a plate heat exchanger according to the invention before the installation of inlet and outlet fittings, which can be manufactured and operated according to a preferred embodiment of the method according to the invention. [Figure 1B] 1 shows diagrammatically and in perspective a preferred configuration of a plate heat exchanger according to the invention after installation of inlet and outlet fittings, which can be manufactured and operated according to a preferred embodiment of the method according to the invention. [Diagram 2] 1 shows diagrammatically preferred construction details of a plate heat exchanger according to the invention; [Diagram 3] 1 shows a schematic diagram of a preferred embodiment of the method according to the invention as a block diagram. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] In FIG. 1 a preferred configuration of a plate heat exchanger according to the invention is shown diagrammatically and in perspective and designated 1 .

[0037] The plate heat exchanger 1 according to FIG. 1A has a cubic central body 8 with 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 alternating arrangement of dividing sheets 20 and fins 11, 12. Thus, the central body 8 of the plate heat exchanger 1 has a number of dividing sheets and a number of fins, each of which is arranged between two adjacent dividing sheets. Both the dividing sheets and the fins can be made, for example, from aluminum. On their sides, the fins 11, 12 are closed by side bars 4, which can also be made from aluminum, so that side walls are formed as a result of the lamination with the dividing sheet 20. The outer fins (here, 11) of the central body 8 are closed by covers 5 (outer sheets) lying parallel to the fins and dividing sheets and generally also made of aluminum.

[0038] To manufacture the plate heat exchanger 1, the dividing sheets 20, side bars 4, and fins (only fins 11 and 12 are shown here), typically coated with braze, are stacked on top of each other to form the central body 8 illustrated herein, which is then brazed under vacuum in a brazing furnace. Thereafter, the inlet and outlet fittings 6 and 6a required to allow the heat exchange fluids in and out are installed, as shown in FIG. 1B.

[0039] In Fig. 1B, the fittings 6 and 6a can be seen on the top surface of the central body 8, on the side and on the bottom surface of the central body 8. The fittings 6 and 6a, which are located underneath the central body 8 and on the side opposite to the side shown, are partially hidden.

[0040] A fluid or process flow can be fed into the plate heat exchanger 1 and removed again through nozzles 7. The fittings 6 and 6a serve to distribute the fluid introduced through nozzles 7 and to collect and concentrate the fluid to be removed from the plate heat exchanger 1, said distribution and collection being carried out via distribution fins 3 (see FIG. 1A) to the heat exchanger fins 11, 12. Thermal energy is then exchanged within the plate heat exchanger 1 by the various flows of fluid.

[0041] The plate heat exchanger 1 shown in Figure 1 is designed to pass fluid streams through each other in separate passages for heat exchange, some of which can be passed in counter-current directions, others in cross-current directions or simultaneously.

[0042] As will be explained below with reference to FIG. 2, which shows a schematic and perspective view of the details of the plate heat exchanger 1, at least one capillary tube having at least one thermocouple or measuring resistance element is introduced into at least one divided sheet 20 of the plurality of divided sheets.

[0043] As can be seen in FIG. 2, the fins 11 and 12 are arranged side by side with the dividing sheet 20. The fins 11 and 12 are only shown very diagrammatically in that the path they follow is shown on the underside of the details shown here. The channels formed by the fins 11 and 12 run parallel to the section 31, which will be described below. The dividing sheet 20 comprises two partial sheets 21 and 22 in which grooves 23 or grooves 24 are respectively introduced. In these (semi) grooves 23 and 24, in particular, the capillaries 30 are introduced in the dividing sheet 20 in such a way that the capillaries 30 are completely surrounded or covered by the material of the first partial sheet 21 and the second partial sheet 22. It is also possible to introduce only one groove in only one of the partial sheets 21, 22 in which the capillaries are inserted. Conventional dividing sheets or separator plates may for example be used as the partial sheets 21, 22. In particular, the capillary 30 in this case has a first portion 31 inside the dividing sheet 20 and a second portion 32 outside the dividing sheet 20. In the first portion 31 inside the dividing sheet 20, a plurality of mutually spaced thermocouples or measuring resistor elements 40 ("thermocouple or measuring resistor element profile bars") are arranged in the capillary 30, with which temperature values ​​can be recorded along the longitudinal direction of the capillary 30 in the plate heat exchanger 1. The capillary 30 is designed in particular to have a thin wall in the first portion 31 or as a thin stainless steel tube, and in the second portion 32 is enclosed in metal, i.e. is enveloped by metal or is formed as a thicker tube.

[0044] Outside the dividing sheet 20, the capillary tube 30 is led into a transfer point 50, which can be connected by cabling 51 to a computing unit 60, for example a control unit. In particular, the computing unit 60 receives and evaluates the temperature values ​​recorded by the thermocouples or measuring resistor elements 40 and can transmit the resulting data from there, for example by means of a transmitter, to the cloud for further processing. In particular, the computing unit 60 does not have to be located in a process chamber, since the transfer point 50 can take the form of, for example, an interface between a process chamber in which the plate heat exchanger 1 is located and the outside. For example, this 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.

[0045] If the measuring element is a thermocouple, the cabling must optimally be continued in area 51 with the same material as in area 32. Otherwise, unit 60 cannot measure the thermoelectric voltage correctly, unless the temperature at transfer point 50 is also measured and the thermoelectric voltage corrected accordingly. If a measuring resistive element is used, such line connection problems can be avoided.

[0046] As will be explained below with reference to FIG. 3, in which a preferred embodiment of the method according to the invention is shown diagrammatically as a block diagram, the plate heat exchanger 1 is in particular manufactured and operated according to a preferred embodiment of the method according to the invention.

[0047] In this case, a manufacturing process for the plate heat exchanger 1 is indicated at 100. The manufacturing process 100 begins with a step 101 in which a plurality of divided sheets and a plurality of fins are provided.

[0048] The split sheets correspond, for example, to the partial sheets 21 and 22 shown in Figure 2, but in each case do not have grooves. In step 102, grooves are milled into a part of the split sheets in order to obtain the partial sheets 21 and 22 as shown in Figure 2. For example, grooves may be introduced into 25% of the split sheets.

[0049] In step 103, a capillary 30 is in each case introduced between the two sheets 21, 22 provided with grooves in step 102, in order to obtain in each case a split sheet 20 having a capillary 30 as shown in Figure 2. In this example, the split sheet 20 having the capillary 30 is thus twice as thick as the split sheet without it, since the split sheets 20 having the capillary 30 are each made from two such split sheets without capillaries.

[0050] In step 104, brazing is applied to the surfaces of the divided sheets in a process chamber, for example a furnace, after which the divided sheets and the fins are stacked one on top of the other. For example, in this case every fourth divided sheet may be a divided sheet 20 with a capillary 30, so that here adjacent divided sheets (partial sheets) have to be joined by brazing. After stacking, in step 105, the individual capillaries 30 are each connected to a computing unit via a transfer point, and in step 106, the divided sheets and the fins are joined to each other in a furnace with a material joint by brazing.

[0051] During brazing, in step 107, temperature values ​​in the plate heat exchanger are recorded using thermocouples or measuring resistance elements 40 in the capillary tubes 30 and transmitted to a computing unit. Based on or depending on the recorded temperature values, in step 108, the further brazing process is monitored. In particular, in this case, the temperature distribution in the plate heat exchanger is advantageously monitored in order to prevent the formation of gaps in the plate heat exchanger due to the fact that the dividing sheets and the fins are loosely or not yet firmly bonded due to differences in thermal expansion and the resulting deformations during the brazing operation.

[0052] If the fins and the split or partial sheets are well bonded to each other, then in step 109 the fixtures 6, 6a, nozzle 7 and cover are attached to the plate heat exchanger 1. If the plate heat exchanger 1 is successfully manufactured, then in step 110 the capillary tube 30 can be separated from the computing unit 60.

[0053] Even after the manufacturing process has been successfully carried out, it is possible for the capillary tube 30 to remain in the plate heat exchanger 1 and for a thermocouple or measuring resistor element 40 to be used to record temperature values ​​during normal operation, as described below.

[0054] Normal operation of the plate heat exchanger 1 is indicated by 200 in Figure 3. In step 201 the capillary tube 30 is reconnected to a computing unit, e.g. a control unit. In step 202 the two fluids are made to pass in opposite directions through the plate heat exchanger 1 to perform indirect heat exchange.

[0055] In step 203, during this operation of the plate heat exchanger, temperature values ​​are recorded by means of a thermocouple or measuring resistor element 40 in the capillary tube 30. In step 204, the operation of the plate heat exchanger 1 is controlled in an open or closed loop depending on these recorded temperature values. In particular, in this case, the operation can be optimized so that the remaining life of the plate heat exchanger 1 can be increased.

[0056] Also in step 205, depending on the recorded temperature values, the life consumption or remaining life of the plate heat exchanger 1 is determined. For example, the temperature values ​​can be used to determine thermal or mechanical stresses in the plate heat exchanger 1, and depending on the stresses, the life consumption and remaining life of the plate heat exchanger 1 can be determined.

[0057] In step 206, the recorded temperature values ​​are conveniently stored in a computing unit so that they are available for later comparison with recorded temperature values.

[0058] Thus, according to the invention, it is possible to carry out temperature recordings during the manufacturing process of the plate heat exchanger 1, during the brazing of the fins and the dividing sheets, and also during normal operation of the plate heat exchanger 1, using a similar temperature measuring device in the form of a thermocouple or measuring resistance element 40 in the capillary tube 30. The thermocouple or measuring resistance element 40 used during the manufacturing process to monitor the brazing can also continue to be used in normal operation.

[0059] Explanation of symbols 1 Plate Heat Exchanger 3 Distribution fins 4. Sidebar 5 Cover 6 Mounting fixture 6a Mounting fixture 7 Nozzles 8 Central Body 11 Finn 12 Finn 20 split sheet 21 Partial Sheet 22 Partial Sheet 23 Groove 24 groove 30 Capillary 31 First part of the capillary 32 Second part of the capillary 40 Thermocouple or measuring resistance element 50 Transfer Points 51 Line 60 Computing Units 100 Manufacturing process 101~110 Method steps 200 Normal operation 201~206 Method steps

Claims

1. A method for manufacturing a plate heat exchanger (1) having a plurality of divided sheets (20) and a plurality of fins (11, 12), each of the fins being disposed between two adjacent divided sheets, At least one capillary tube (30) having at least one thermocouple and / or measuring resistive element (40) is introduced (103) into at least one of the plurality of divided sheets (20); A method in which in each case dividing plates and fins are arranged in alternating order (104) and bonded to one another with a material bond (106).

2. 2. The method of claim 1, wherein a temperature value is recorded (107) upon coupling at a material junction by the at least one thermocouple and / or measuring resistive element (40) in the at least one capillary (30).

3. 3. The method according to claim 1 or 2, wherein the dividing sheet (20) and the fins (11, 12) are joined together (106) with a material bond by a brazing process, in particular by a vacuum brazing process.

4. The method according to any one of the preceding claims, wherein said at least one capillary (30) is introduced (103) into a groove (23, 24) of said at least one dividing sheet (20).

5. The method according to any one of claims 1 to 4, wherein the at least one divided sheet (20) is formed from a first partial sheet (21) and a second partial sheet (22) having adjacent surfaces.

6. 6. The method according to claim 4, wherein the grooves (23, 24) are introduced into at least one of the two adjacent surfaces of the first partial sheet (21) and the second partial sheet (22).

7. 7. The method according to claim 1, wherein the at least one capillary (30) is formed by a thin wall (31) in a first portion (31) that is inside the at least one dividing sheet (20) and / or the at least one capillary (30) is encapsulated in metal (32) in a second portion (32) that is outside the at least one dividing sheet (20).

8. The method according to any one of the preceding claims, wherein the at least one capillary (30) is withdrawn from a process chamber in which bonding at the material joint is carried out.

9. A method for operating a plate heat exchanger (1) manufactured by the method according to any one of claims 1 to 8, comprising the steps of: A first fluid and a second fluid are passed through the plate heat exchanger (202); A method according to claim 1, wherein temperature values ​​are recorded (203) during operation of the plate heat exchanger (1) by means of the at least one thermocouple and / or measuring resistive element (40) in the at least one capillary tube (30).

10. 10. The method according to claim 9, wherein the operation of the plate heat exchanger (1) is controlled (204) in an open loop and / or a closed loop manner depending on the temperature values ​​recorded during the operation of the plate heat exchanger (1).

11. 11. The method according to claim 9 or 10, wherein the life consumption and / or remaining life of the plate heat exchanger (1) is determined (205) depending on the temperature values ​​recorded during operation of the plate heat exchanger (1).

12. The method according to any one of claims 9 to 11, wherein the operating history of the plate heat exchanger (1) is determined depending on the temperature values ​​recorded during operation of the plate heat exchanger (1).

13. A plate heat exchanger (1) having a plurality of divided sheets (20) and a plurality of fins (11, 12), each of which is arranged between two adjacent divided sheets of the plurality of divided sheets, and at least one capillary tube (30) having at least one thermocouple and / or measuring resistance element (40) is arranged in at least one divided sheet (20) of the plurality of divided sheets.

14. 14. The plate heat exchanger according to claim 13, wherein the at least one dividing sheet (20) is formed from a first partial sheet (21) and a second partial sheet (22) having mutually adjacent surfaces, grooves (23, 24) are introduced into at least one of the two adjacent surfaces of the first partial sheet (21) and the second partial sheet (22), and the at least one capillary (30) is arranged in the groove (23, 24).

15. A plate heat exchanger according to claim 13 or 14, produced by the method according to any one of claims 1 to 7.

16. A plate heat exchanger according to any one of claims 13 to 15, designed to be operated according to the method according to any one of claims 8 to 11, and having a control unit designed in particular to carry out the method according to any one of claims 8 to 11.

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