Plate-shaped thermal conduction element

Abstract

The invention relates to a plate-shaped heat-conducting element and a heat exchanger comprising the plate-shaped heat-conducting element.

Description

SUBJECT OF THE INVENTION

[0001] The invention relates to a plate-shaped heat-conducting element and a heat exchanger comprising the plate-shaped heat-conducting element. BACKGROUND OF THE INVENTION

[0002] A heat exchanger is a device used to transfer thermal energy from a source to a destination. This transfer can occur between two media without them coming into direct contact, or directly from a heating element to a surrounding fluid. Heat exchangers are available in many shapes and sizes and are found in a wide variety of applications, from heating, ventilation, and air conditioning (HVAC) systems to heat exchange in industrial processes.

[0003] In indirect heat transfer, the media between which heat is transferred are separated by a solid wall to prevent mixing. Heat transfer occurs through conduction across the separating material. Typical examples include plate heat exchangers, shell and tube heat exchangers, and finned tube heat exchangers.

[0004] In direct heat transfer, heat is transferred directly from a heating element (such as a heating coil or heating rod) to a surrounding fluid (such as a gas, a liquid, especially water, or another fluid). This transfer occurs through convection and partly through radiation. Examples include water heaters, radiators, and air heaters.

[0005] Heat exchangers are commonly used in the chemical, pharmaceutical, steel, semiconductor, solar, and environmental industries, as well as many other sectors. They are frequently used to heat a fluid using hot, pressurized steam. However, this process has significant drawbacks, particularly in applications involving the heating of corrosive fluids.

[0006] Even with proper system design, corrosive fluids in particular can place significant stress on the heat exchanger material over time. The use of steam can exacerbate this, especially if the steam also contains impurities that can have a corrosive effect. Steam is generally used at higher temperatures, meaning that the temperature difference between the corrosive fluid and the steam is typically high. This can lead to increased thermal stress on the heat exchanger material, which in turn can shorten its service life. Furthermore, the need to use materials resistant to both the corrosive fluid and the high temperatures and pressures of the steam can limit material selection and thus increase costs.

[0007] Furthermore, precise temperature control can be difficult when using steam as a heating fluid. This can be particularly problematic if the corrosive fluid cannot tolerate high temperatures, as this could lead to damage or reduced efficiency in the processes the fluid undergoes. The use of steam also necessitates appropriate safety precautions, as steam poses a particular hazard at high pressures. If the heat exchanger is damaged, especially by corrosion, this can lead to leaks or, in the worst case, equipment failure.

[0008] Heat transfer elements, as used in modern heat exchangers, typically include a flow restrictor with one or more elements that can form so-called flow channels. These channels guide the flow of the medium(s) (e.g., water, oil, air) passing through the heat exchanger. The flow channel is essential for efficient heat transfer.

[0009] The flow channel ensures that the fluid flows evenly and in a controlled manner along one of the plate surfaces. The correct shape and arrangement of the channels optimizes the contact between the fluid and the plate surface, thus improving heat transfer.

[0010] The flow channel also helps to avoid dead zones or areas with little or no fluid flow. In such areas, no or only limited heat transfer would occur, reducing the efficiency of the heat exchanger. The flow channel thus contributes to a uniform distribution of the fluid and enables a high heat transfer rate.

[0011] The specific design of the flow channel allows for influencing the velocity and direction of the flow in a particular area of ​​the heat exchanger, and thus also the heat transfer. In recent years, research has focused on adapting flow channel geometry, particularly by incorporating special structures such as flow breakers to increase the proportion of laminar flow. While the inclusion of such flow breakers does improve heat transfer, it significantly increases manufacturing complexity. Furthermore, especially when using composite materials as the base for the heat transfer element, a high degree of material variability is observed, leading to inconsistent heat input into the fluid being heated. TASK

[0012] Against this background, the object of the present invention was therefore to provide a heat conducting element that enables heating with the highest possible efficiency and safety, while at the same time being easy to implement in terms of design and / or being versatile and / or additionally enabling significantly greater flexibility and service life. DESCRIPTION OF THE INVENTION

[0013] This problem is solved according to the invention in particular by a plate-shaped heat conducting element for use in a plate heat exchanger comprising ▪ two flat sides, namely a first cover surface and a second cover surface opposite it, preferably at least partially, particularly preferably completely parallel, the distance between which defines the heat-conducting element thickness D WE; ▪ a circumferential surface (also called side surface) connecting the two cover surfaces; ▪ at least one through-opening extending through the two flat sides of the plate-shaped heat-conducting element. wherein at least one of the two cover surfaces has a flow channel arrangement for the passage of a heat transfer fluid, which has a plurality of flow channels with a flow channel depth T SR and a flow channel width B SR encompasses and wherein the multitude of flow channels has a varying flow channel depth T SR exhibits. DEFINITIONS

[0014] A plate is a body in which two dimensions (length and width) are significantly larger than the third dimension (thickness). The flat sides extending along the length and width dimensions are the largest surfaces of the plate and, in the context of a plate heat exchanger, are the primary surfaces for interaction with the preferably corrosive fluid. These surfaces are also referred to as the first and second cover surfaces. Preferably, the first and second cover surfaces are at least partially, and preferably completely, parallel to each other. In another preferred embodiment, the first and second cover surfaces are not parallel to each other, but rather at an angle, preferably converging at an acute angle. α≤ 20°, preferably ≤ 10°. This results in wedge-shaped plate structures, which have the advantage that the volumes within the flow channels can be varied and the heat-conducting elements can thus be optimized for their application. The inventors found that this is particularly advantageous in evaporation applications.

[0015] A heat exchanger, also called a heat transfer apparatus, is a technical device or apparatus used to transfer heat to a medium. It is used to raise or lower the temperature of the medium by transferring heat indirectly or directly. These devices are of central importance in many industrial and technical processes. A plate-shaped heat-conducting element according to the invention enables direct heat transfer to a preferably corrosive fluid without the need for a second fluid for heat exchange.

[0016] A fluid is a material that can deform when a force is applied without retaining a fixed shape. Fluids can exist in the liquid or gaseous states and are characterized by their ability to move and adapt easily when external forces are applied to them. Preferably, the fluid is a liquid.

[0017] The most important properties of fluids are their ability to flow and the fact that they exert a force in all directions but have no fixed structure.

[0018] The heat transfer fluid releases heat or absorbs it in the heat exchanger.

[0019] A flow channel arrangement is an area on at least one of the two cover surfaces of the heat conducting element in which flow channels run in a structured and planned arrangement and together form a system for controlling fluid flows.

[0020] Preferably, a flow channel consists of an elongated, one-sided open structure that controls, guides and optimizes the flow behavior.

[0021] Each flow channel has a flow channel depth T SR, x and a flow channel width B SR, x. Both parameters can vary along the course of the channel.

[0022] The feature according to the invention, in which the plurality (i.e., two or more) of flow channels have a varying flow channel depth, can be achieved by two different basic designs. Firstly, the flow channel depth TSR,x can vary within a flow channel; secondly, the individual flow channels can have a constant depth, but the flow channel depths of at least two flow channels (e.g., TSR,x1 and TSR,x2) can differ. Naturally, these two designs can also be combined, i.e., the flow channel depth within a flow channel and the flow channel depth of different flow channels can differ from one another.

[0023] A through-hole is an opening that can be used, for example, for the inlet and / or outlet of a heat transfer fluid. Through-holes thus allow the inlet and / or outlet of a heat transfer fluid to / from one of the two cover surfaces, with the flow channel arrangement typically being placed between an inlet through-hole and an outlet through-hole, and the heat transfer fluid flowing from the inlet through-hole via the flow channel arrangement to the outlet through-hole.

[0024] Preferably, the through-openings are circular in shape. Circular geometries ensure uniform pressure distributions along the circumference of the opening, thus preventing structural weaknesses and also offering minimal flow resistance for the heat transfer fluid.

[0025] In another preferred embodiment, the through-holes are not circular. Non-circular openings can help to direct the flow and focus it in a specific direction. Preferably, the through-holes are oval, slotted, or olive-shaped. Oval or olive-shaped through-holes allow for a higher flow velocity of the heat transfer fluid. Non-circular openings are also easier to integrate into confined or irregular geometries. In particular, if the fluid contains multiple components, a non-circular opening can promote mixing by generating turbulence or distributing the flow unevenly.

[0026] Each opening has a cross-sectional area, where the cross-sectional area corresponds to the area that results when the cut is made orthogonally to the direction of flow.

[0027] The inventors discovered that varying the channel depth TSR allows for a very simple increase in the proportion of turbulent flow, without the need for additional structural elements such as flow breakers. The turbulence effects within the fluid caused by varying the channel depth result in chaotic water movement with strong flow fluctuations and a slowing of the flow rate. Turbulent flow significantly improves heat transfer compared to laminar flow. The main reason for this is the increased mixing created by the eddies and irregular flow patterns of turbulent flow. These eddies promote the exchange of energy between different layers of the fluid, allowing warmer fluid to come into contact with colder surfaces or layers more quickly, and vice versa.

[0028] This results in a significantly higher heat transfer coefficient in turbulent flows. The turbulent motion reduces the thickness of the thermal boundary layer, which acts as a barrier to heat transfer in laminar flows. The disruption and reduction of this boundary layer significantly enhances heat transfer.

[0029] Furthermore, turbulent flow results in higher convective heat transfer. The chaotic flow patterns lead to stronger velocity gradients and higher energy dissipation, making heat transfer significantly more efficient. This explains why heat transfer is particularly effective compared to laminar flow.

[0030] In laminar flows, heat transfer remains limited to molecular conduction effects, resulting in lower efficiency. The ordered, parallel flow allows only slow heat transfer through the thick and stable thermal boundary layer.

[0031] The varying depths of the flow channels allow for locally variable energy input. This can, for example, compensate for thermal cooling effects at the outer edge of the plate or for variations in material quality.

[0032] Integrating the through-hole directly into the flat sides of one of the two or more plates offers several significant advantages. Firstly, this design promotes a compact and stable structure, as separate connectors or fittings that would otherwise need to be attached externally to the housing structure are eliminated. This can reduce both material costs and assembly effort, and leads to increased structural integrity of the heat exchanger.

[0033] Furthermore, this through-hole, integrated directly into the plate, allows for improved flow dynamics of the preferably corrosive fluid. Since disruptive flow interruptions and dead spaces, which often occur at the transitions between external connections and the internal flow chamber, are reduced, optimized heat transfer efficiency is achieved.

[0034] Directly routing the through-hole through the flat sides of the plates can also contribute to a more homogeneous heat distribution. This allows the preferably corrosive fluid to flow through the plate heat exchanger at a more uniform temperature, resulting in higher thermal efficiency of the system.

[0035] Examples of materials that can be used to manufacture the plate-shaped thermal interface material are selected from the following group: carbon materials, preferably graphite; composite materials; ceramics, preferably silicon carbide (SiC); plastics, preferably PTFE, PVDF, PFA, PEEK; glass, glass-ceramics, enamel, niobium, tantalum, stainless steel, and combinations thereof. The plate-shaped thermal interface material can therefore comprise or consist of these materials.

[0036] The term carbon material also includes partially or completely graphited or graphitic carbon materials.

[0037] Carbon materials, especially resin-impregnated carbon materials, are particularly preferred. Composite materials, such as composites of carbon materials and fiber materials and / or fluoropolymers, can also be used to advantage; as can coated materials, for example, metals with a fluoropolymer coating. Metals (e.g., steel) with a coating or cladding of a special metal such as tantalum or niobium can also be used to advantage. Composite materials comprising carbon materials and fluoropolymers are particularly preferred due to their excellent density and stability.

[0038] However, materials that are essentially free of fluoropolymers, i.e., have a weight fraction of fluoropolymers ≤ 1 wt.% or even ≤ 0.1 wt.%, are also preferred. This allows for a particularly advantageous design from an environmental perspective.

[0039] In a preferred embodiment, the plate-shaped heat-conducting element consists at least partially, preferably completely, of a composite material.

[0040] The composite material preferably comprises at least one material component, a fiber material, preferably comprising or consisting of long and / or continuous fibers, and a further component, a matrix material, in particular a polymer material, in which the fiber material is at least partially arranged. In this context, polymer is understood to be a chemical substance that contains over 50 wt.%, preferably over 70 wt.%, more preferably over 80 wt.%, even more preferably over 90 wt.%, and most preferably over 95 wt.% macromolecules.

[0041] "Macromolecules" are molecules composed of one or more identical or similar structural units, the constitutional repeating units (IUPAC Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"), A.D. McNaught, A. Wilkinson, Blackwell Scientific Publications, Oxford (1997), S.J. Chalk. ISBN 0-9678550-9-8). Such macromolecules have more than 10 repeating units, preferably more than 15. The molar mass is preferably at least 3,000 g / mol, more preferably at least 5,000 g / mol, more preferably at least 7,000 g / mol, and most preferably at least 10,000 g / mol.

[0042] Polymers are typically produced by the polymerization reaction of monomers or oligomers, which possess one or more of the constitutional repeating units. An oligomer is defined as a molecule formed from several monomers and therefore composed of a multitude of structurally identical or similar structural units. Within the scope of the invention, the term oligomer is used when the molecule is produced from a reaction of 2-10, preferably 2-8, and particularly preferably 3-7 monomers.

[0043] According to the invention, "resins" are understood to be precursors of thermoset plastics, i.e., polymers (cf. IUPAC Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"), A.D. McNaught and A. Wilkinson, Blackwell Scientific Publications, Oxford (1997)). )),which can be used in particular as components of coatings, varnishes and paints. Resins obtained by polyaddition or polycondensation are especially preferred.

[0044] The matrix material of the composite material serves to at least partially embed the fiber material. It holds the fibers of the fiber material in their position and transmits and distributes stresses between them. It is preferably a polymer material, in particular a thermosetting polymer material. Preferably, it is a thermosetting polymer material made from a resin and a hardener. Accelerators, activators, and release agents are preferably used in the manufacturing process and, according to the present invention, are then preferably part of the matrix material.

[0045] Preferably, the matrix material, with the exception of the incorporated fiber material, has a substantially homogeneous chemical composition, i.e., material boundaries, with the exception of the incorporated fiber material, do not exist at all or only exist with adjacent areas of the fiber composite component.

[0046] Preferably, the plate-shaped heat-conducting element has a permeability coefficient (gas permeability) of c(perm) ≤ 5 * 10⁻⁴ cm² / s, more preferably c(perm) ≤ 1 * 10⁻⁴ cm² / s, even more preferably c(perm) ≤ 8 * 10⁻⁵ cm² / s, considerably more preferably c(perm) ≤ 5 * 10⁻⁵ cm² / s, and most preferably c(perm) ≤ 2 * 10⁻⁵ cm² / s or even ≤ 1 * 10⁻⁵ cm² / s. The inventors found that a correspondingly low permeability coefficient improves long-term stability. In particular, this results in high thermal and chemical resistance. A correspondingly low permeability can be achieved, particularly in porous materials such as carbon materials or SiC, by impregnation. The impregnation is preferably carried out with a phenolic or vinyl ester resin, wherein the plate(s) is / are preferably impregnated once, twice, three times, or more.A phenolic or vinyl ester resin is preferably used as the impregnating resin. The permeability coefficients mentioned above can be determined using the vacuum decay method according to DIN 51935:2019-07.

[0047] Preferably, the plate-shaped heat-conducting element is corrosion-resistant, i.e., the component sections in contact with the fluid are made of a material that is stable under standard conditions against acids with a pKs ≤ 7, more preferably ≤ 2, even more preferably ≤ 0, and most preferably ≤ -2, and bases with a pKb ≤ 7, more preferably ≤ 2, even more preferably ≤ 0, and most preferably ≤ -2, i.e., it shows no significant decomposition, in particular no material loss, or reduction in performance. The material used is particularly preferably stable even at temperatures up to 80°C, more preferably 150°C, or even 200°C.

[0048] In a preferred embodiment, when using a composite material, the fiber material of the composite material is carbon, aramid, or glass fiber. Carbon, aramid, or glass fiber-reinforced composite materials exhibit high strength and material resistance as well as high thermal conductivity and are therefore suitable for use in heat exchanger devices, particularly when using corrosive heat exchanger fluids.

[0049] Carbon fiber reinforced carbon (CFC) is particularly preferred. CFC exhibits exceptionally high mechanical stability, even at high temperatures, thus allowing the use of particularly thin heat transfer element geometries without the risk of material fatigue and / or failure.

[0050] Alternatively or additionally, the plate-shaped heat-conducting element can also comprise or consist of a carbide material, such as SiC. This can also be impregnated, preferably with a resin.

[0051] Sintered silicon carbide offers particularly high hardness and strength, excellent thermal conductivity and high chemical resistance, making it especially suitable for demanding applications such as heat transfer equipment, particularly for corrosive fluids.

[0052] In a preferred embodiment, the plate-shaped heat-conducting element comprises or consists of a carbon material, preferably graphite. The use of graphite or another carbon material offers excellent corrosion resistance and enables high thermal and electrical conductivity, which can improve the efficiency of the heat exchanger and significantly increase its service life.

[0053] Preferably, the proportion of carbon material in the plate-shaped heat-conducting element is ≥ 40 vol.%, more preferably ≥ 50 vol.%, even more preferably ≥ 70 vol.%, considerably more preferably ≥ 90 vol.%, and most preferably 100 vol.%. The inventors have determined that, above a corresponding carbon content, the chemical and mechanical resistance necessary for demanding process engineering applications, particularly plants handling corrosive chemicals, is achieved.

[0054] In another preferred embodiment of the plate-shaped heat transfer element, the carbon material is impregnated with a resin, preferably a phenolic resin. Impregnation of the carbon material with a resin such as phenolic resin can improve the structural integrity of the plates, increase their mechanical strength, and enhance their resistance to corrosive chemicals, thus contributing to the longevity of the plate heat exchanger in demanding operating environments.

[0055] In a preferred embodiment, the plate-shaped heat-conducting element comprises or consists of a metal, preferably a metal selected from the group consisting of tantalum, niobium, zirconium, nickel, titanium, as well as alloys and combinations of the aforementioned, in particular tantalum and nickel-based alloys. Due to its excellent corrosion resistance, even under extreme conditions, tantalum offers high reliability in process engineering applications, especially those involving corrosive fluids. Tantalum is characterized by its high resistance to acids and other aggressive substances, which extends the service life of the heat-conducting element and increases its operational reliability.

[0056] The materials are particularly preferred for their stability against strong acids such as HCl, HNO 3 , HF, H 3 PO 4 , H 2 SO 4 and / or strong alkalis such as NaOH, especially at temperatures up to 150°C or even 200°C.

[0057] Stability against hydrochloric acid with an HCl concentration of 35% at a temperature of 110 °C is particularly advantageous.

[0058] Preferably, the plate-shaped heat-conducting element is pressure-stable in a range of -1 to 20 bar, more preferably 0 to 15 bar, and most preferably 1 to 10 bar.

[0059] In a preferred embodiment of the invention, the maximum flow channel depth T SR,max ≤ 10 mm, preferably ≤ 5 mm. Such a flow channel depth ensures that the heat transfer is sufficiently large and time-invariant when used in a heat exchanger.

[0060] Even a small deviation in the channel depth ΔT SR (also called channel depth variance) in relation to the maximum channel depth T SR,maxcan produce the effects according to the invention. The flow channel depth deviation is the difference between the maximum flow channel depth T. SR,max and minimum channel depth T SR,min .

[0061] In a preferred embodiment of the invention, the flow channel depth deviation ΔT SR ≥ T SR , max 200 preferred ≥ T SR , max 100 , even more strongly preferred ≥ T SR , max 50 , even more strongly preferred ≥ T SR , max 20 and at ≥ T SR , max 10 The flow channel depth deviation ΔT SR is preferably also ≤ T SR , max 2 , even preferred ≤ T SR 3 , and preferably ≤ T SR , max 4 .

[0062] Preferably, the flow channel depth deviation ΔT SR moves within a range of until T SR , max 2 , more strongly preferred in an area of T SR , max 100 until T SR , max 3 , and preferably in an area of T SR , max 50 until T SR , max 4 .

[0063] Preferably, the channel depth varies within a flow channel (i.e., individual channel depth TSR, x varies) such that the turbulence effects described above occur within a flow channel; that is, the above-mentioned channel depth variations are observed along the course of an individual flow channel. For this purpose, the channel depth variation of an individual flow channel can fall within the range outlined above. Alternatively or additionally, the channel depth can vary between different flow channels. In particular, the channel depth of a first flow channel can be invariant and differ from a second with a similarly invariant channel depth. This can be used, for example, to compensate for material differences or cooling effects. Turbulence effects can then be intensified, especially at the convergence of flow channels with different channel depths.

[0064] Preferably the flow channel depth is in a range of 1 to 30 mm or 1 to 10 mm, preferably 1 to 7 mm, particularly preferably 2 to 7 mm, even more preferably 2 to 6 mm and most preferably 2 to 5 mm.

[0065] A channel depth above this range leads to insufficient heat transfer, especially with a low proportion of turbulent flows, for example when the channel depth deviation is only slight.

[0066] However, a flow channel depth below this range leads to an insufficient mass flow rate when used in a heat exchanger, which makes the corresponding heat transfer process inefficient.

[0067] Preferably, the minimum heat-conducting element thickness DWE is ≥ 1 mm, more preferably ≥ 2 mm, even more preferably ≥ 3 mm, and most preferably ≥ 4 mm. However, the maximum heat-conducting element thickness is typically also ≤ 25 mm.

[0068] A greater thickness of the heat-conducting element offers increased mechanical stability, as thicker plates are more robust and resistant to mechanical stresses such as pressure, tension, or impact. This significantly extends the service life, especially in corrosive applications.

[0069] Another advantage is improved thermal inertia. Thicker heat-conducting elements can store heat more effectively and conduct temperature fluctuations more slowly. This results in more uniform heat transfer, which is particularly important in applications with a narrow outlet temperature range. At the same time, they are less susceptible to thermal deformation and stress caused by temperature differences.

[0070] Thicker heat-conducting elements also offer better resistance to penetration by liquids, gases, or solid objects, which is particularly important in corrosive applications. Protection against corrosion and wear is also improved, as more material is present before structural damage occurs. At the same time, the load-bearing capacity of the plate increases, thereby enhancing the structural stability of a heat exchanger formed by the plates.

[0071] Another advantage is the reduction of vibrations and resonances. Due to their higher natural frequency, thicker plates dampen vibrations better, which is beneficial in machines and systems.

[0072] However, heat-conducting elements with excessive thickness require an enormous amount of material and lead to a significant increase in weight, which makes handling considerably more difficult, especially during installation or maintenance.

[0073] Preferably, the flow channel is corrugated or profiled. Particularly preferably, corrugations or profiles are arranged in the bottom or wall of the flow channel.

[0074] Wavy refers to a structure that preferably exhibits regular upward and downward movements in a curved shape. It is characterized by alternating elevations and depressions, which can be harmonic, periodic, or irregular. Wavy, as defined in the invention, also includes jagged structures, which can also be described as wave-like with corners.

[0075] Profiled refers to a structure that features a specific, often repeated, and spatially emphasized shape or contour. In a heat-conducting element, this shape serves as a functional feature, for example, to reinforce the plate-shaped heat-conducting element and / or to optimize the flow properties of a fluid guided through the flow channels. The profiling can be selected from the following groups: grooved structure, wave structure, ribbed profile, slotted profile, perforation, edging, stamping, milling, press profile, and embossing.

[0076] It is particularly preferred that the flow channel walls or the flow channel floor are profiled in the longitudinal direction of the flow channels, so that the velocity of the fluid to be guided is not excessively affected.

[0077] Alternatively, the walls or bottom of the flow channels can also be profiled in the transverse direction of the flow channels. This further increases the turbulence within the heat transfer fluid.

[0078] In a preferred embodiment, the flow channels themselves are shaped like waves or profiles. Particularly preferably, the flow channel walls are also shaped in this way. Even more preferred is the shape of the flow channels or flow channel walls along an axis extending from the fluid inlet to the outlet opening, in a wave-like or profiled manner. This increases heat transfer by generating turbulent flow without significantly affecting the fluid flow.

[0079] To increase the turbulence generated by the heat-conducting element, the flow channels can be at least partially interrupted and / or offset from one another. An offset arrangement offers numerous advantages, particularly in fluid dynamics and thermal engineering applications. It generates increased turbulence, which ensures better flow mixing and makes heat transfer more efficient. The enhanced turbulence reduces the thickness of the thermal boundary layer, accelerating heat exchange between the surface and the fluid. Furthermore, the offset arrangement promotes a more uniform flow distribution by minimizing dead zones or stagnant areas.

[0080] Another advantage is the reduction of deposits, as lower flow velocities and the associated accumulation of particles or dirt are avoided. At the same time, the targeted increase in pressure drop allows for better control of the flow velocity. These properties contribute to optimizing energy efficiency, since improved heat transfer often permits a more compact design and lower energy consumption. Furthermore, the more uniform pressure distribution reduces flow instabilities and oscillations.

[0081] In a preferred embodiment, the flow channel arrangement is arranged in a first cover surface section of the area A D1 of a cover surface and the cross-sectional area of ​​the at least one through-opening corresponds to the area AQ , wherein the ratio A D 1 A Q The ratio is in the range of 5-700. Preferably, the ratio is in the range of 7-650, even more preferably in the range of 10-620, and most preferably in the range of 15-600. Preferably, the ratios refer to the cross-sectional area of ​​exactly one through-hole. These ratios enable efficient and optimal heat transfer by optimizing the fluid flow while simultaneously improving the mechanical load and optimizing flow velocities and turbulence generation.

[0082] Advantageously, the top surface section of surface A D1 is limited by external side walls, for example by the external side walls of a housing structure.

[0083] Preferably, the ratio between the first cover surface section and the total area of ​​the respective cover surface is in the range of 0.5 - 0.99, more preferably 0.6 - 0.9, and most preferably 0.7 - 0.8. This provides a sufficiently large area with flow channels for active heat transfer.

[0084] In a preferred embodiment, the first cover surface section has a first subsection of surface A D1, U1, which serves as an inflow or outflow area away from or towards the through-opening and for supplying the medium to or away from the main flow zone. Typically, in this neck region, the flow channel width B SR of the flow channels varies and / or the flow channel does not have a curved path but is straight and may only contain a maximum change of direction in the form of a kink. In the main flow zone, the second subsection of surface A D1, U2, the flow channel width B SR of the flow channels is typically constant and / or the path of the channels themselves includes several changes of direction ("kinks").

[0085] This ensures a uniform flow distribution of the heat transfer fluid across the entire plate surface. Areas where the flow channel width BSR of the flow channels varies form efficient distribution structures that contribute to the uniformity of the heat transfer fluid flow distribution.

[0086] Preferably, the ratio of the area of ​​the first subsection A D1 , U1 to the area of ​​the second subsection is A D1 , U2 A D 1 , U 1 A D 1 , U 2 in the range of 1 / 3 - 1 / 15, more preferably in the range of 1 / 4 - 1 / 12 and most preferably in the range of 1 / 5 - 1 / 10.

[0087] The ratio of the area of ​​the first subsection A D1 , U1 to the cross-sectional area of ​​the at least one through-opening A Q A D 1 , U 1 A Q preferably lies in the range of 1 / 3 - 200, more preferably in the range of 1 / 2 - 150 and most preferably in the range of 1 - 120.

[0088] Preferably, especially in the case of a flat flow channel bottom, the angle between the flow channel walls and the channel bottom is in the range of 60°–120°, preferably 70°–110°, and most preferably 80°–100°. While small angles promote focus and velocity of the transported medium, they also increase turbulence and sediment deposition. Large angles facilitate a uniform flow distribution but can create dead zones. The inventors found that the above ranges are ideal for heat transfer.

[0089] In another preferred embodiment, the flow channels can have different geometries depending on their proximity to the inlet and outlet openings.

[0090] In a preferred embodiment, the plate-shaped heat-conducting element is characterized in that the flow channels run parallel at least in sections.

[0091] This parallel arrangement of the flow channels ensures a uniform flow of the corrosive fluid through the flow chamber and contributes to efficient and homogeneous heat transfer. The parallel routing of the flow channels minimizes the risk of dead zones, which is particularly advantageous with regard to the durability and efficiency of the heat exchanger.

[0092] Furthermore, the parallel alignment of the channels can lead to simplified manufacturing and increased reproducibility of flow characteristics across different heat exchangers. This not only facilitates the maintenance and cleaning of the heat exchanger components but also enables more precise design for specific applications, particularly in corrosive environments.

[0093] To further maximize the heat transfer area and increase turbulence in the fluid flows and / or to enable a more compact design, both deck surfaces can feature a flow channel arrangement with a multitude of flow channels.

[0094] Furthermore, the invention relates to a plate heat exchanger comprising at least two plate-shaped heat conducting elements according to the invention.

[0095] The flow space (also called "intermediate space") located between two flat sides of two plate-shaped heat-conducting elements defines the space in which the fluid can flow and heat is transferred from the plate-shaped heat-conducting element(s) to the medium (e.g., the fluid). The flow space is preferably the entire space located between the two flat sides of two plate-shaped heat-conducting elements. Naturally, a plate heat exchanger preferably comprises several such flow spaces, since it typically has significantly more than two plates. For the sake of linguistic simplicity, the term "flow space" will be used in the following, even if several such intermediate spaces between the heat-conducting elements are present, unless a single flow space is explicitly designated as such.

[0096] A flow obstruction within a heat exchanger is an element designed to influence the flow of a fluid through the flow space between heat-conducting elements. The flow obstruction is part of the plate-shaped heat-conducting element and is arranged on the "flat" base structure of the heat-conducting element. The flow obstruction can take on various forms, including, but not limited to, ribs, webs, baffles, or guide structures. It also serves to form the flow channel arrangement, including the flow channels according to the invention, which increase the contact time of the fluid with the heat-transferring surfaces, induce turbulence, and thus improve the heat exchange between the fluid and the plate surfaces.

[0097] The flow obstruction, or at least one or more elements thereof, is / are preferably connected to one or more basic elements of the two or more plate-shaped heat-conducting elements by a material-, form- or force-fit connection; a material-fit connection is particularly preferred.

[0098] A monolithic design of the flow obstruction and the "flat" base structure of the heat-conducting element is particularly preferred. The flow obstruction, or one or more of its elements, can be manufactured, for example, from a single block using subtractive manufacturing. Alternatively, the flow obstruction (or one or more of its elements) can also be obtained by pressing a mass into a mold. Monolithic designs of the plate-shaped heat-conducting element with flow obstruction can likewise be manufactured using subtractive manufacturing or by pressing.

[0099] Advantageously, the flow space is limited by external side walls, for example, by the outer side walls of a housing structure. The plate heat exchanger is preferably constructed to be fluid-tight.

[0100] In a preferred embodiment, the flow obstruction forming the flow channels is designed in such a way that it divides a preferably corrosive fluid guided through the flow space into two or more, at least sectionally, separate material flows.

[0101] This type of flow restriction design results in a targeted division of the fluid flow, thus contributing to improved heat distribution and heat transfer by allowing the fluid flow to be guided more efficiently over the plate-shaped heat-conducting elements. This targeted flow guidance can increase the contact time of the fluid with the heat-transferring surfaces and thereby enhance the thermal performance of the plate heat exchanger.

[0102] Distributing the preferably corrosive fluid into separate flows can also lead to more efficient utilization of the available flow volume by minimizing pressure drop and achieving a more uniform fluid distribution. Such a design can also offer advantages in avoiding temperature spikes (hotspots) and minimizing corrosion, as a uniform temperature distribution throughout the flow chamber is ensured. In particular, combined with the ability of the plate-shaped heat transfer element(s) as heat exchanger(s) to transfer heat more quickly and in a more spatially and temporally focused manner, highly customized and optimized heat transfer scenarios can be implemented, enabling the heat exchanger to be used extensively in demanding industrial environments.

[0103] In a preferred embodiment, the corrosion-resistant plate heat exchanger is designed such that the preferably corrosive fluid is in direct contact with at least one of the two or more plate-shaped heat-conducting elements. This enables direct and efficient heat transfer between the corrosive fluid and the plates of the heat exchanger, resulting in increased heat transfer efficiency. The direct contact ensures that the heat is transferred from the plates to the fluid without additional barriers, which is particularly important in applications requiring high precision in temperature control or where maximum energy efficiency is crucial.

[0104] In a preferred embodiment, ≤ 70 vol.%, more preferably ≤ 50 vol.%, even more preferably ≤ 30 vol.%, and particularly preferably ≤ 20 vol.% of the flow chamber is filled with the at least one flow obstruction. This limitation of the volume fraction of the flow obstruction in the flow chamber ensures that sufficient space remains for the effective flow of the preferably corrosive fluid and that a correspondingly high throughput can be achieved.

[0105] Preferably, ≥ 5 vol.%, more preferably ≥ 10 vol.%, and particularly preferably ≥ 15 vol.% of the flow chamber is filled with the at least one flow obstruction – especially in combination with one of the maximum limits mentioned above. These lower limits for the volume fraction of the flow obstruction in the flow chamber ensure that good heat transfer can take place and that the formation of flow paths can be sufficiently influenced.

[0106] In a preferred embodiment, the flow obstruction is designed such that it allows at least partial, preferably complete, immersion by a preferably corrosive fluid. Preferably, the flow obstruction comprises one or more elements that are completely accessible to the fluid from all sides, for example, ribs or pins that can be surrounded by the fluid from all sides.

[0107] The possibility of complete immersion ensures that all areas of the surfaces are uniformly reached by the preferably corrosive fluid, which promotes a homogeneous temperature distribution and thus uniform heat transfer. This continuous and uniform exposure of the surfaces to the fluid reduces the risk of temperature spikes (hotspots) and can extend the service life of the plate-shaped heat-conducting elements by preventing uneven stress.

[0108] Complete fluid circulation can also help minimize deposits and contaminants on the heat-conducting element surfaces, as the continuous flow of fluid can lead to a self-cleaning effect. This simplifies maintenance and ensures that the heat exchanger's performance is maintained even during long-term operation in corrosive environments.

[0109] The plate-shaped heat-conducting elements according to the invention can also be used in electrically heated plate heat exchangers without any design modification, so that the invention continues to relate to an electrically heated plate heat exchanger comprising at least two plate-shaped heat-conducting elements according to the invention. Such electrically heated heat exchangers can have a resistance or induction heating element, which is preferably arranged partially, more preferably completely, inside or outside one of the at least two heat-conducting elements.

[0110] In a further preferred embodiment of the invention, the plate heat exchanger is a heat exchanger. A plate heat exchanger is a heat exchanger used to transfer heat between two fluids without them coming into direct contact with each other. In this heat exchanger, two or more fluids are alternately passed through the individual flow chambers located between two plate-shaped heat-conducting elements, such that one fluid flows through every other flow chamber and the other fluid flows through the remaining flow chambers. For the supply and discharge of the preferably corrosive fluids, such a heat exchanger has several inlet and outlet openings.Due to the high turbulence in the flow through the flow channels with their varying flow channel depths and the large surface area of ​​the heat-conducting elements available for heat exchange, the heat transfer in a plate heat exchanger according to the invention between the fluids is very efficient.

[0111] In embodiments as heat exchangers, the invention can additionally enable heat exchange between the media by indirect or direct electrical heating or cooling. Alternatively, heat can also be transferred (partially or completely) from one of the two or more plate-shaped heat-conducting elements, which can be directly or indirectly electrically heated or cooled, to a first fluid, which in turn then heats or cools a second fluid. In the heat exchanger embodiments with electrical heating or cooling, this can therefore be combined with heat transfer between two or more fluids. A design change of the heat-conducting elements is not necessary for this.

[0112] Directly or indirectly electrically heated or cooled refers to the property of a plate-shaped heat-conducting element or its components (including connected components, such as connected heating elements) that their thermal states – i.e., the temperature of their components – can be manipulated by electrical energy either directly or indirectly, for example by induction. Thus, a conversion of electrical energy into heat energy takes place.

[0113] Direct electrical heating or cooling means that electrical energy is directly converted into heat or cold energy, preferably within one of the plate-shaped heat-conducting elements or one of its components. Examples include heating elements such as resistance heaters, which are inserted into or attached to the plate-shaped heat-conducting element and heat the fluid via the Joule effect (current flow through an electrical resistance generates heat), or Peltier elements, which cool directly via the thermoelectric effect.

[0114] Indirect electrical heating or cooling uses electrical energy to generate or remove heat elsewhere. An example of indirect heating is electromagnetic induction heating, where heat is generated in the plate-shaped heat-conducting element by means of induced eddy currents.

[0115] Direct or indirect electrical heating or cooling also includes heating or cooling elements directly or indirectly connected to the plate-shaped heat-conducting element, which heat and / or cool at least one of the two or more plate-shaped heat-conducting elements.

[0116] In a preferred embodiment of the plate heat exchanger, at least one electrical heating or cooling element is arranged at least partially, preferably completely, directly or indirectly (for example, via a thermally conductive film or paste) in contact with at least one of the two or more plate-shaped heat-conducting elements, i.e., connected to it directly or indirectly. Such a connection can be, for example, form-fit, material-fit, or force-fit.

[0117] The combination of the terms "heatable or coolable" describes the possibility of temperature control in both directions - both heating and cooling - which gives the device a flexible adaptability to different operating conditions and process requirements.

[0118] Electric heating offers higher efficiency compared to conventional methods by enabling more precise, i.e., more spatially and temporally directed and faster, heat transfer. More efficient use of the heat transfer surfaces leads to a reduction in the required size of the heat exchanger, resulting in cost and space savings.

[0119] The possibility of continuous heating and rapid start-up and shut-down contributes to process flexibility and can reduce operating costs. Compared to the use of heat transfer media such as steam, which are introduced into the system at high temperature and lose heat during transit, electric heating enables a constant heat transfer rate, if desired, regardless of the position within the heat exchanger. Furthermore, electric heating allows for the use of individual heat sources for different plate-shaped heat-conducting elements within the system, ensuring a uniform and defined temperature distribution. This optimizes heat transfer and enables a more homogeneous heat flow.

[0120] In a preferred embodiment, the plate heat exchanger has a heating element comprising a planar electrical conductor, for example made of metal or graphite, and one or more insulated electrical conductors, such as a stranded wire, which is or are able to generate an alternating magnetic field in order to generate heat in the planar electrical conductor.

[0121] This specific heating element enables efficient and uniform heat generation within the plate-shaped heat transfer element, which directly contributes to regulating the temperature of the preferably corrosive fluid. The use of an alternating magnetic field to heat the flat electrical conductor represents an inductive heating method characterized by high energy efficiency, rapid response time, and precise local control. This technology allows for accurate and controlled heat distribution within the plate heat exchanger without direct electrical contact with the fluid, thus increasing system safety, particularly in corrosive environments.

[0122] In a preferred embodiment, the plate heat exchanger has a heating element in which the insulated electrical conductor described above runs in a meandering shape, at least in sections.

[0123] The meandering pattern of the insulated electrical conductor enables a uniform propagation of the alternating magnetic field across the entire surface of the conductor. This arrangement contributes to efficient heat generation and ensures a homogeneous temperature distribution in the preferably corrosive fluid flowing through the heat exchanger. The meandering conductor pattern can also improve the efficiency of the inductive heating process by maximizing surface area utilization and reducing response time. This makes the heat exchanger particularly suitable for applications requiring precise and rapid temperature adjustments.

[0124] In general, the heating or cooling element preferably has meandering sections or is entirely meandering. A meandering arrangement also allows for a more homogeneous temperature distribution, for example, in resistance heating.

[0125] A spiral shape for the insulated electrical conductor is also preferable.

[0126] In a preferred embodiment, the plate heat exchanger comprises a resistance heating element, which may have the meandering or spiral shape described above. This element is preferably arranged at least partially within one of the two or more plate-shaped heat-conducting elements.

[0127] Typically, such a heat exchanger according to the invention comprises a housing structure which serves to hold two or more plate-shaped heat-conducting elements in a stacked, preferably parallel arrangement and to at least partially, preferably completely surround them, thereby creating together with the plates an arrangement in which the fluid can flow, preferably completely sealed to the outside.

[0128] Preferably, the heat exchanger is corrosion-resistant, i.e., the component sections in contact with the fluid are made of a material that is stable under standard conditions against acids with a pKs ≤ 7, more preferably ≤ 2, even more preferably ≤ 0, and most preferably ≤ -2, and bases with a pKb ≤ 7, more preferably ≤ 2, even more preferably ≤ 0, and most preferably ≤ -2, i.e., it shows no significant decomposition, in particular no material loss, or reduction in performance. The material used is particularly preferably stable even at temperatures up to 80°C, more preferably 150°C, or even 200°C.

[0129] The two or more plate-shaped heat-conducting elements of the heat exchanger can have different functions. For example, one of the two heat-conducting elements can be solely a heating plate, while the other solely conducts the preferably corrosive fluid. However, the functions can also be combined in such a heat-conducting element; that is, the heat-conducting element conducts the fluid and simultaneously serves for heating because a heating element is at least partially arranged in or on the heat-conducting element. For example, such a heat-conducting element can be made of graphite and have the media guide provided on one flat side, while on the opposite side, strands for inductive heating are provided, preferably embedded.

[0130] Preferably, a seal is inserted between each of the two or more plate-shaped heat-conducting elements. This seal preferably comprises a fluoropolymer-based sealing system, more preferably a sealing cord based on PTFE. This requires very low sealing forces and exhibits advantageously high flow properties. In other preferred embodiments, the seal comprises a corrosion-resistant sealing system, preferably a sealing paste. This seals the system and prevents the escape of the preferably corrosive fluid, particularly at higher pressures.

[0131] Alternatively or additionally, a seal can be made entirely of a carbon material, especially graphite. This is particularly preferred as a sealing paste or sealing cord.

[0132] Preferably, the seal is free (i.e., the weight fraction is ≤ 1 wt.%, preferably ≤ 0.1 wt.%) of fluorine compounds. In particular, the seal is free of per- and / or polyfluorinated compounds. This results in particularly durable designs.

[0133] Alternatively or additionally, the plate-shaped heat-conducting elements can be bonded together by a material-bonded connection, preferably by adhesive bonding. Preferably, the material-bonded connection is achieved using phenolic resin or sealant. Choosing a material-bonded connection as an alternative to a gasket offers the advantage that the plate heat exchanger can be used without a gasket.

[0134] The plate heat exchanger according to the invention preferably comprises two adjacent plate-shaped heat-conducting elements whose flow channel arrangement is aligned with each other, more preferably such that a mirror plane is formed between the two adjacent plate-shaped heat-conducting elements. Such an arrangement enables the plate heat exchanger to be used as an evaporator, since a large space can be created for the liquid to be evaporated.

[0135] The invention therefore also relates to an evaporator which comprises at least two of the plate-shaped heat-conducting elements according to the invention.

[0136] The invention further relates to a process engineering plant comprising a heat exchanger according to the invention.

[0137] The robust construction, especially when using corrosion-resistant materials, makes the heat exchanger ideal for critical applications in sectors such as chemical engineering, biotechnology, pharmaceuticals, food processing, and energy technology. This enables the construction of process plants with high process stability and reliable operation in a wide variety of industrial environments. EXAMPLES

[0138] The present invention will be explained in more detail below with reference to the embodiment of a plate heat exchanger for heating a corrosive fluid shown in the figures. Brief description:

[0139] Fig. 1 shows a side view of a heat exchanger according to the invention. Fig. 2 shows a perspective front view of a heat exchanger according to the invention. Fig. 3 shows a perspective rear view of a heat exchanger according to the invention. Fig. 4shows a cross-sectional view of a plate pack of a heat exchanger according to the invention as shown in the Figs. 1-3 depicted. Fig. 5 shows a top view of the front side of a plate-shaped heat-conducting element for conveying corrosive fluids, as in a plate pack of the Fig. 4 used. Fig. 6 shows a top view of the back side of a plate-shaped heat-conducting element for conveying corrosive fluids, as in a plate pack of the Fig. 4 used. Fig. 7 shows a top view of a heating plate as in a plate pack of the Fig. 4 used. Fig. 8 shows a top view of a frame, as in a heating plate. Fig. 7 is used. Fig. 9 shows a top view of a heating unit, as in a hot plate. Fig. 7 is used. Fig. 10 shows a cross-sectional view of a plate pack of a heat exchanger according to the invention with sequential media flow. Fig. 11shows a cross-sectional view of a plate pack of a heat exchanger according to the invention with parallel media routing. Fig. 12 shows a partial section of a flow channel arrangement comprising two flow channels Fig. 13 Shows a partial section of a flow channel. Cross-sectional view along the flow direction of the medium. Detailed description:

[0140] Fig. 1 Figure 1 shows a side view of a heat exchanger according to the invention, which is specifically designed to preferably conduct and heat corrosive fluids. The heat exchanger comprises a centrally arranged plate pack. 8, A key element of the heat exchanger comprises several stacked, plate-shaped heat-conducting elements. These plate-shaped heat-conducting elements are designed to reliably guide the preferably corrosive fluid during operation while simultaneously heating or cooling it.

[0141] The clamping plate and the frame plate 2, 3 The frame structure of the heat exchanger is made of steel and serves as support elements for the central plate pack. 8. They ensure the necessary stability and the design allows the heat exchanger to safely absorb the stresses that occur during operation, such as those caused by the flow of the preferably corrosive fluid or by temperature fluctuations.

[0142] The clamping and frame plate 2, 3 The formed frame structure is supported by compression springs. 1 The compression springs serve to exert a uniform and controlled pressure on the plate pack in order to ensure a firm and tight arrangement of the individual plate-shaped heat-conducting elements and to optimize the thermal contact between the plate-shaped heat-conducting elements.

[0143] The clamping plate and the frame plate 2, 3These elements serve as pressure distribution components, transferring the force exerted by the springs evenly to the underlying plate pack. This homogeneous pressure distribution is advantageous for efficient heat transfer and for protecting and sealing the heat exchanger against potential damage from uneven loads. Preferably, a seal is incorporated between each of the plate-shaped heat-conducting elements, which is compressed by the applied pressure. This seals the system and prevents the escape of the preferably corrosive fluid, even at higher pressures.

[0144] Fig. 2 and Fig. 3 concern perspective representations of the in Fig. 1 The heat exchanger according to the invention is shown. The access point for the wiring. 4This connection allows electrical wiring, sensors, or control cables to be routed into the interior of the heat exchanger. This connection is essential for integrating measurement and control technology, which is beneficial for the operation and monitoring of the heat exchanger. It also supplies power to the electric heating element.

[0145] Via the inlet opening located on the frame plate 5 The preferably corrosive fluid is introduced into the heat exchanger. Its size and position are precisely tailored to the flow rate and requirements of the specific application. This ensures that the corrosive fluid can be effectively guided through the plate pack of the heat exchanger, where the heat transfer process takes place.

[0146] Through the optional elements, namely the sealed access for wiring 6 and the sealed inlet opening 7,The heat exchanger is designed to be adaptable to various requirements. These sealed access points may be intended for future expansions or upgrades, but are not currently in use and are therefore securely sealed to prevent leaks or contamination.

[0147] On the frame plate 3 opposite chipboard 2 are the output for the wiring 9 as well as the exit opening 10 The system is arranged for the discharge of the preferably corrosive fluid. Depending on the flow direction of the preferably corrosive fluid, the inlet and outlet openings can also be reversed. The cable access point can also be used as an outlet, depending on the application. vice versa.

[0148] Fig. 4Figure 1 shows a detailed sectional view of the plate pack of the heat exchanger shown in previous figures. The plate pack comprises plate-shaped heat-conducting elements for conveying preferably corrosive media. 19 and heating plates 20. In general, the plate-shaped heat-conducting elements for conveying preferably corrosive media can simultaneously perform the heating or cooling function, i.e., the stacked plate package is formed from only one type of plate.

[0149] The plate-shaped heat-conducting elements for guiding the preferably corrosive fluid are located in the center of the sectional view. 19,which define the flow space by means of flow restrictions. These plate-shaped heat-conducting elements are specifically designed to safely guide corrosive liquids or gases. Their special properties and the material from which they are made ensure that they can withstand the aggressive properties of the preferably corrosive fluid. They are made, for example, of graphite, silicon carbide, a fluoropolymer, or tantalum. The design of these plate-shaped heat-conducting elements enables efficient and controlled flow.

[0150] The heating plates 20, the space between the plate-shaped heat-conducting elements for conveying corrosive media 19 Positioned within these elements, they play a crucial role in the heat transfer process. They are electrically heated and then transfer this heat to the plate-shaped heat-conducting elements for the conduction of the preferably corrosive fluid. 19,which in turn transfers the heat to the fluid moving through the flow chamber.

[0151] At the end of the disk pack are the end disks. 23 The plates are arranged as end elements of the plate stack and are designed to distribute the pressure evenly within the plate pack to achieve uniform heat transfer. The end plates are also robustly constructed to withstand the mechanical stresses that can arise from the operating pressure of the flowing, preferably corrosive, fluid.

[0152] In Fig. 5 A top view of the front of a plate-shaped heat-conducting element for guiding the preferably corrosive fluid is shown, as it is arranged in a plate pack according to the illustrations in Fig. 4 is used.

[0153] The entrance opening 5(first through-opening) serves to supply the preferably corrosive fluid, which is to be heated or cooled in the flow chamber.

[0154] A key feature of the plate-shaped heat-conducting element is the flow channel arrangement located on at least one of the cover surfaces, which is formed by the flow obstruction elements. This controls and maximizes the path taken by the preferably corrosive fluid through the plate-shaped heat-conducting element. The flow channel arrangement is located in a first cover surface section of surface A D1, which, in the illustrated arrangement, has two subsections.

[0155] The first surface section comprises a first subsection of the surface A D1 , U1 ("neck area") 11a,which in turn comprises two sub-areas. A first sub-area contains the flow channels leading away from the first opening, where the flow channel width BSR varies, or more precisely, increases. A second sub-area contains the flow channels leading towards the second opening, where the flow channel width BSR also varies, or more precisely, decreases. The first surface section further includes a second sub-section of surface AD1,U2 ("main flow zone") with a corrugated profile and a constant flow channel width BSR.

[0156] The variation in the flow channel depth lies within a range of T SR , max 100 until T SR , max 3 .

[0157] Additionally, the plate-shaped heat-conducting element has openings for wiring. 21These bushings allow the integration of sensors or other electrical components that may be required for monitoring, regulating, and controlling the heat transfer process. In particular, the bushings allow the electrical supply to the electric heating element to be routed to the heating plate. Fig. 6 The figure shows the flat second surface, i.e., the back of the plate-shaped heat-conducting element. Of course, both surfaces, i.e., the front and back of the plate-shaped heat-conducting element, can also be designed with flow restrictions to guide the preferably corrosive fluid and thus define the flow space.

[0158] Fig. 7 shows a top view of a heating plate, which is an integral part of the [unclear text] in the Fig. 4 The described plate stack is included. The heating plate comprises a feedthrough for the preferably corrosive fluid. 22,which facilitates the passage of the preferably corrosive fluid to the plates for the passage of the preferably corrosive fluid 19 made possible.

[0159] The frame is an essential component. 14, which has an opening in which the heating element 13 is arranged. The heating element comprises a loop-shaped stranded wire structure, which is arranged within a double-walled structure consisting of two cover steel plates. The loop-shaped stranded wire structure, arranged between the flat plates, inductively heats the steel plates, so that the heating element provides a maximum surface area for heat transfer and thus enables uniform heating of the plate-shaped heat-conducting elements for conveying the preferably corrosive fluid.

[0160] The wiring access to the heating element is also shown. This access point is for the electrical connection of the heating element and allows for the safe and protected routing of the necessary wiring. Through this access point, the heating element can be powered and monitored, which is advantageous for maintaining the correct operating temperatures and for the overall operation of the heat exchanger. Fig. 8 shows the frame without a heating element inside, whereas Fig. 9 The heating element is shown in isolation (cover steel plate not shown).

[0161] Fig. 10 shows a cross-sectional view of a plate pack of a heat exchanger according to the invention, as already described in Fig. 4The figure illustrates a sequential media flow. The preferably corrosive fluid flows through the inlet opening for the corrosive fluid, which is located at the first elongated end of the plate, into the first flow chamber formed by the end plate and a first plate-shaped heat-conducting element for conveying the preferably corrosive fluid. At its opposite elongated end, it is guided through the openings in the heating plate into the next flow chamber, which is formed by two adjacent plate-shaped heat-conducting elements for conveying corrosive media. This creates a meandering flow through the plate stack.

[0162] In contrast, in Fig. 11 An arrangement with parallel fluid guidance is shown, in which, after entering the stack of plates, a partial flow is supplied to the parallel flow chambers.

[0163] Fig. 12 Figure 1 shows a section of a flow channel arrangement comprising two flow channels. The diagram depicts a cross-sectional view perpendicular to the flow direction of the medium. The two adjacent flow channels have an identical flow channel width BSR, but varying flow channel depths (TSR,x1 and TSR,x2).

[0164] Fig. 13 This shows a partial section of a flow channel. The diagram depicts a cross-sectional view along the flow direction of the medium. The channel base has a corrugated shape, resulting in varying channel depths TSR. The maximum heat-conducting element thickness DWE is also shown. 28 for the specific section. Reference sign

[0165] 1 Compression spring 2 Clamping plate 3 Frame plate 4 Access for wiring 5 Inlet opening for supplying the preferably corrosive fluid 6 Optional access for wiring (sealed) 7 Optional inlet opening for supplying the preferably corrosive fluid (sealed) 8 Stacked plate package with heat-conducting elements for heating the preferably corrosive fluid 9 Wiring outlet 10 Outlet opening for draining the preferably corrosive fluid 11a First subsection of the first cover surface section with area A D1,U1 11b Second subsection of the first cover surface section with area A D1,U2 12 Flat surface 13 Heating element 14 Frame 15 Wiring access to the heating element 16 Wiring access into the heating element 17 Recess for heating element 18 Flow direction of the preferably corrosive fluid 19 Plate-shaped heat-conducting element for conducting the preferably corrosive fluid 20 Heating plate 21 Feedthrough for wiring 22 Feedthrough for the preferably corrosive fluid 23 End plates 24 Meandering wiring 25 Flow channel width B SR 26 Flow channel depth T SR, x1 27 Flow channel depth T SR, x2 28 Heat-conducting element thickness D WE , max,

Claims

1. Plate-shaped heat-conducting element for use in a heat exchanger comprising ▪ two flat sides, namely a first cover surface and a second cover surface opposite it, preferably at least partially parallel, the distance between which is the heat conducting element thickness D WE defined; ▪ a circumferential surface connecting the two cover surfaces, ▪ at least one through-opening extending through the two planar sides of the plate-shaped heat-conducting element, wherein at least one of the two cover surfaces has a flow channel arrangement for the passage of a heat transfer fluid, which has a plurality of flow channels with a flow channel depth T SR and a flow channel width B SR includes characterized by the fact that the multitude of flow channels a varying flow channel depth T SR exhibits.

2. Plate-shaped heat-conducting elementaccording to one of the preceding claims, wherein the plate-shaped heat conducting element consists at least partially, preferably completely, of a material selected from the group consisting of carbon materials, composite materials and SiC, preferably graphite and SiC.

3. Plate-shaped heat-conducting element according to one of the preceding claims, wherein the maximum flow channel depth T SR,max ≤ 10 mm, preferably ≤ 5 mm.

4. Plate-shaped heat-conducting element according to one of the preceding claims, wherein the flow channel depth varies within a flow channel.

5. Plate-shaped heat-conducting element according to one of the preceding claims, wherein the minimum heat conducting element thickness D WE, min ≥ 1 mm, preferably ≥ 2 mm.

6. Plate-shaped heat-conducting elementaccording to one of the preceding claims, wherein the flow channels comprise flow channel walls and a flow channel bottom, wherein the flow channel, the flow channel bottom and / or the flow channel walls are corrugated or profiled.

7. Plate-shaped heat-conducting element according to one of the preceding claims, wherein the flow channels are at least partially interrupted and / or offset from each other.

8. Plate-shaped heat-conducting element according to one of the preceding claims, wherein the flow channel arrangement is located in a first cover surface section of area A D1 is arranged and the cross-sectional area of ​​the at least one through-opening of area A Q corresponds, whereby the ratio A D 1 A Q in the range of 3-1000.

9. Plate-shaped heat-conducting element according to claim 8, wherein the first cover surface section of surface A D1 a first subsection of area A D1,U1 exhibits, in which the flow channel width BSR the flow channels vary and a second subsection of area A D1,U2 exhibits, in which the flow channel width B SR the flow channels are constant.

10. Plate-shaped heat-conducting element according to claim 9, wherein the ratio of A D 1 , U 1 A Q in the range of 1-200.

11. Plate-shaped heat-conducting element according to one of the preceding claims, wherein both cover surfaces have a flow channel arrangement with a plurality of flow channels.

12. Plate heat exchanger comprising at least two plate-shaped heat-conducting elements according to one of the preceding claims.

13. Plate heat exchanger according to claim 12, wherein the at least two plate-shaped heat-conducting elements are materially bonded to each other.

14. Plate heat exchanger according to claim 12, wherein the at least two plate-shaped heat-conducting elements are connected to each other by means of a fluoropolymer-based sealing system.

15. Plate heat exchangeraccording to one of claims 12-14, wherein the cover surfaces of two adjacent plate-shaped heat-conducting elements, which have a flow channel arrangement, are arranged in an alignment with each other, preferably such that a mirror plane is formed between the two adjacent plate-shaped heat-conducting elements.

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