Diaphragm device including layered structure
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-06-02
- Publication Date
- 2026-04-07
AI Technical Summary
Diaphragm devices in pressure sensors are susceptible to damage from volatile and reactive components in process media, leading to mechanical stress and permeation issues.
A diaphragm device with a layered structure comprising a first layer with a higher coefficient of thermal expansion than the diaphragm section and a second layer with lower permeability to the process medium, acting as a buffer and barrier to reduce thermal and mechanical stress, thereby protecting the diaphragm from damage.
The layered structure effectively prevents damage from process media by reducing thermal and mechanical stress, ensuring uniform permeation and enhancing the durability and measurement accuracy of the diaphragm device.
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Abstract
Description
[Technical Field]
[0001] The present invention relates to a diaphragm device having a layer structure applied to at least a portion of the diaphragm.
[0002] A layer structure generally refers to a stack or sequence of layers of different materials, which can be produced, for example, by methods of thin film or thick film technology. Corresponding methods, such as physical or chemical vapor deposition, as well as further processes for treating corresponding layers, such as photolithography or laser trimming, are known from the prior art.
[0003] In an exemplary configuration, the layer structure is a thin-film layer structure, which is advantageous because the features and examples described in the following sections can be implemented, inter alia, selectively by means of thin-film technology.
[0004] The diaphragm section to which the layer structure is deposited or applied is also referred to in this context, particularly within the scope of this description, as substrate.
[0005] Diaphragm devices with a layer structure are used, for example, in the technical field of measurement technology. For example, German Patent Application Publication No. 102007047707 discloses a pressure measuring cell. The cell has a substrate to which an insulating layer is applied. This insulating layer is followed by a measuring layer with conductor tracks, which are finally at least partially covered with a passivation or protective layer. In this case, the flexible diaphragm section of the pressure measuring cell is called the substrate, and this substrate is supported all around by the rigid edge section of the pressure measuring cell.
[0006] Such diaphragm devices are often used to measure pressure in industrial process equipment. In this case, the side of the flexible diaphragm section remote from the layer structure is exposed to a process medium, such as a gas under pressure or a liquid under pressure. Changes in the pressure of the process medium cause the flexible diaphragm section to deflect with different magnitudes. The resulting expansion or compression of the flexible diaphragm section can be detected by a strain resistor integrated into the layer structure.
[0007] However, the diaphragm or the measuring circuit in the layer structure may be damaged, especially if the process medium contains volatile and / or reactive components.
[0008] Problem to be solved by the invention Against this background, it is an object of the present invention to provide a diaphragm device that is less susceptible to or better protected from damage by process media and / or other environmental influences, and to provide a pressure sensor and a use of the diaphragm device in which these advantages are likewise achieved.
[0009] This problem is solved by a diaphragm arrangement which, with respect to the diaphragm arrangement, embodies the features of claim 1. Advantageous refinements of the diaphragm arrangement are the subject of the dependent claims.
[0010] With regard to the pressure sensor, this problem is solved by a corresponding device according to claim 14 and with regard to the use by that according to claim 15.
[0011] Summary of the Invention A first aspect of the present invention relates to a diaphragm device comprising a flexible diaphragm section, a first side of which is exposed to or adapted to be exposed to a process medium, and a second side of which has a layer structure. That is, the layer structure is deposited on, disposed on, or embedded within the surface of the second side of the flexible diaphragm section. The first and second sides of the diaphragm section are opposite sides of the diaphragm section. In this case, the flexible diaphragm section can also be referred to as a substrate on which the layer structure is disposed or deposited, for example, by a vapor deposition process, as described in the prior art.
[0012] The layer structure comprises at least a first layer and a second layer. The first layer has a thermal expansion coefficient that lies between the thermal expansion coefficient of the diaphragm section and the thermal expansion coefficient of the second layer. The thermal expansion coefficient (actually sometimes also called the coefficient of thermal expansion or simply the coefficient of expansion) is a material parameter that describes how much a body made of the relevant material expands when heated. The thermal expansion coefficient is usually expressed in units [K -1 A high coefficient of thermal expansion means that the associated material expands strongly when heated or contracts strongly when cooled. For example, if the second layer has a lower coefficient of thermal expansion than the material of the flexible diaphragm section, it is desirable for the first layer to have a coefficient of thermal expansion that is higher than that of the second layer and lower than that of the flexible diaphragm section.
[0013] The second layer has a lower permeability for the process medium or at least one component of the process medium than the corresponding permeability of the diaphragm section for the same process medium or the same component of the process medium. In this case, permeability is a material characteristic that describes the degree to which a body made of the relevant material is permeable to atoms or molecules of a particular gas or liquid that have a concentration or pressure gradient on two sides of the body (e.g., front and back of the body). A substance, i.e., a gas or liquid, whose atoms or molecules pass through (i.e., penetrate) the material is also called a permeant in this context, and the process is also called permeation. Regarding the permeation of a material layer of a given thickness, it can be seen that for most materials, permeation decreases with increasing layer thickness but increases with increasing pressure or concentration difference of the permeant between the two sides of the layer. Furthermore, the permeability of a material can be temperature-dependent. Additionally, permeability can vary for different permeants, which is often referred to as selective permeability. Due to these various dependencies of permeability, permeability is sometimes quantified by a so-called permeability coefficient, but in practice is specified in many different units, which typically depend on the method used to measure the material index. Thus, absolute values may vary from source to source, and ratios of values for different materials measured by the same method are highly relevant. In this specification, some expressions relating to atoms or molecules of a permeant are omitted, for example, to express, as a shorthand, that a permeant penetrates or permeates a material, or that a material or layer has a specific permeability to a specific permeant. In other words, according to the present invention, if the material of the second layer is selected so that the permeability of the second layer to the process medium or a component of the process medium is lower than the permeability of the flexible diaphragm section, this means that atoms or molecules of the process medium or a component of the process medium can penetrate the second layer more slowly or to a lesser extent than they penetrate the flexible diaphragm section.
[0014] According to the present invention, a first layer is directly or indirectly applied to the diaphragm section, and a second layer is directly or indirectly applied to the first layer. For purposes of this specification, when one layer is directly applied to another layer, this means that there is no other layer or layers between the two layers. When one layer is indirectly applied to another layer, this also means that there is another layer or layers disposed between the two layers.
[0015] The diaphragm structure according to the present invention advantageously achieves high resistance to damage by the process medium. Permeation of the process medium or components of the process medium can be substantially prevented or at least significantly slowed or controlled. Furthermore, uneven permeation over the surface of the flexible diaphragm segment is prevented, or permeation occurs at least significantly more uniformly over the surface of the flexible diaphragm segment covered by the layer structure. Therefore, locally varying degrees of damage, which could impair the durability or other functions of the diaphragm structure, are avoided.
[0016] These advantages are achieved thanks to the innovative combination of several factors. By selecting the thermal expansion coefficient of the first layer, the first layer effectively acts as a buffer against thermal expansion effects between the flexible diaphragm section and the second layer. Therefore, if no first layer is disposed between the flexible diaphragm section and the second layer, mechanical stresses that would normally occur between the flexible diaphragm section and the second layer due to significantly different thermal expansion coefficients during temperature changes are dramatically reduced. Such mechanical stresses are also referred to as thermal stresses below. Thermal stresses become more pronounced the greater the difference in the thermal expansion coefficients of adjacent layers or materials. The first layer distributes the total difference in the thermal expansion coefficients between the flexible diaphragm section and the second layer across the two interfaces, reducing the respective differences and thus the thermal stress. In combination with the selected permeability of the second layer, this effect leads to particularly efficient reduction of damage due to permeation of the process medium or its components. The buffering effect of the first layer on thermal stress allows the second layer to maintain high quality over time, i.e., the second layer is not susceptible to, or at least significantly less susceptible to, microcracks or other damage that may occur due to thermal stress over time or even during the fabrication of the layer structure. Such microcracks or damage can cause non-uniform transmission across the surface of the layer structure. Therefore, the first layer plays an essential role in ensuring that the second layer can achieve its low transmission rate uniformly across the entire surface of the layer structure.
[0017] In an exemplary configuration of the diaphragm device, the permeability of the second layer or a sublayer contained in the second layer to the process medium or a component of the process medium is greater than the corresponding permeability of the diaphragm section by a factor of at least 100, preferably by a factor of at least 1000, particularly preferably by a factor of at least 10. 6 This configuration allows the barrier effect of the second layer against permeation to be achieved particularly efficiently.
[0018] In this specification, when a first layer or a second layer is mentioned, this in each case means at least one homogeneous layer made of a particular material. On the other hand, when one or more sublayers of a first layer or a second layer are mentioned, as in the previous and next sections, this in each case means one or more layers from a layer stack made of different materials. Thus, in such exemplary embodiments, the first layer or the second layer may in each case comprise a stack of different sublayers, but each sublayer always meets all the requirements that the individual first layer or second layer must also meet.
[0019] In a further exemplary configuration of the diaphragm device, the first layer or a sublayer contained within the first layer has a structural constant that is between the structural constants of the diaphragm section and the second layer. Specifically, this structural constant may be the lattice constant of the deposited layer or the average interatomic distance within the layer. In this manner, the second layer can effectively prevent or at least dramatically reduce mechanical stresses that may arise between the flexible diaphragm section and the second layer due to differences in structural constants. Such mechanical stresses do not initially arise due to differences in expansion characteristics with temperature changes, but rather primarily arise at boundary layers when adjacent layers or materials have different structural constants. Therefore, such mechanical stresses are also referred to as intrinsic stresses hereinafter. Similar to the first layer's role as a thermal stress buffer, the first layer in this configuration also acts as an intrinsic stress buffer, thereby eliminating or at least significantly reducing the effects of microcracks and other potential damage.
[0020] In a further exemplary configuration of the diaphragm device, the first layer or a sublayer contained therein has a lower permeability to the process medium or a component of the process medium than the corresponding permeability of the diaphragm section. As a result, the first layer or the corresponding sublayer of the first layer can already exert a barrier effect, i.e., can effectively prevent or at least significantly slow down the permeation of the process medium or a component of the process medium. As a result, the second layer can be protected even more efficiently, and the diaphragm structure can be further improved in terms of its durability and other functions.
[0021] In a further exemplary configuration of the diaphragm device, the permeability of the first layer or a sublayer comprised in the first layer to the process medium or a component of the process medium is greater than the corresponding permeability of the diaphragm section and / or the corresponding permeability of the second layer by a factor of at least 100, preferably by a factor of at least 1000, particularly preferably by a factor of at least 10. 6 This configuration allows the barrier effect of the first layer against permeation to be achieved particularly efficiently.
[0022] In a further exemplary configuration of the diaphragm device, the first layer or a sublayer included in the first layer has a higher permeability to the process medium or a component of the process medium than the corresponding permeability of the diaphragm segment. As a result, permeation of the first layer can be increased and accelerated, and in use, when the first side of the diaphragm segment is exposed to the process medium, substantially homogeneous and uniform permeation of the first layer by atoms or molecules of the process medium or component of the process medium occurs over a period of time. This also results in more uniform permeation into or through the second layer. In this way, uneven permeation or damage to the second layer by the process medium or component of the process medium can be effectively prevented or at least significantly reduced. This results in improved durability and other functions of the diaphragm device as a whole, and the second layer in particular.
[0023] In a further exemplary configuration of the diaphragm device, the permeability of the first layer or a sublayer comprised in the first layer to the process medium or a component of the process medium is greater than the corresponding permeability of the diaphragm section and / or the corresponding permeability of the second layer by a factor of at least 100, preferably by a factor of at least 1000, particularly preferably by a factor of at least 10. 6 This configuration allows for particularly efficient achievement of the more uniform transmission described in the previous section.
[0024] In another exemplary configuration of the diaphragm device, the first layer or a sublayer included in the first layer is an anchoring layer. The anchoring layer is disposed between two layers of different materials and is characterized by providing stable adhesion to both layers, i.e., at the interfaces of each of the two adjacent layers. In this case, the anchoring layer may be disposed, for example, directly on the flexible diaphragm section, thereby advantageously contributing to the stable adhesion of further sublayers of the first layer or subsequent second layers to each other and ultimately to the flexible diaphragm section. This effectively prevents or reduces damage to the layer structure, such as peeling of individual layers.
[0025] In a further exemplary configuration of the diaphragm device, the first layer includes at least two sublayers, each with a different thermal expansion coefficient, both of which lie between the thermal expansion coefficients of the diaphragm section and the second layer. The sublayers are sequentially applied to the diaphragm section such that the sublayer closest to the second side of the diaphragm section has the smallest difference in thermal expansion coefficient from that of the diaphragm section, and each subsequent sublayer has a larger difference in thermal expansion coefficient from that of the previous sublayer. This configuration allows the first layer to further improve the buffering effect on thermal stress between the diaphragm section and the second layer. The total difference in thermal expansion coefficient between the flexible diaphragm section and the second layer is now distributed over even more intermediate steps or interfaces (compared to a configuration having only a single first layer), thereby further reducing the difference in thermal expansion coefficients, and thus the thermal stress, at each interface between the sublayers of the first layer and the second layer.
[0026] In a further exemplary configuration of the diaphragm device, the first layer has a thickness of 10 nm to 5000 nm, which allows the effects and advantages associated with the first layer, described in the previous section, to be particularly effectively achieved.
[0027] In a further exemplary configuration of the diaphragm device, the second layer or a sublayer included in the second layer has an electrical resistance greater than 10 MOhm, particularly greater than 100 MOhm (MOhm stands for 1,000,000 Ω). The electrical resistance of the second layer or a sublayer included in the second layer refers to the resistance between the lower side of each layer facing the first layer and the upper side of each layer facing away from the first layer. Such a second layer or a sublayer of the second layer can also be referred to as an insulating layer. Advantageously, this insulating layer can effectively electrically insulate further layers following the second layer, such as conductor track layers, from underlying, possibly conductive layers or from flexible diaphragm sections. For example, the insulating layer can be formed from SiO2, which further has very low permeability to volatile substances, such as hydrogen.
[0028] In an exemplary refinement of the preceding configuration of the diaphragm device, the conductor track layer is directly or indirectly applied to a second layer formed as or including an insulating layer. This advantageously provides the diaphragm device with additional functionality. For example, the conductor track layer can be used to create a measuring bridge, which converts the local strain or elongation of the surface of the flexible diaphragm segment into a measurable electrical variable. As a result, when a first side of the diaphragm device is exposed to a pressurized process medium and elastically deforms, the diaphragm device can be used as a sensor element for pressure measurements.
[0029] In such applications, the properties of the diaphragm device can be particularly advantageously utilized. The buffering effect of the first layer against thermal stresses and possibly also inherent stresses, as already explained in the previous section regarding various configurations of the diaphragm device, generally reduces the sensitivity of the sensor element formed by the diaphragm device to environmental influences such as temperature fluctuations. As a result, such a sensor element can achieve higher reliability, stability, and measurement accuracy.
[0030] Furthermore, as already explained in the previous section regarding various configurations of the diaphragm device, the combination of the first and second layers can achieve a very effective barrier effect against the permeation of the process medium or components of the process medium, or at least significantly reduce the permeation. Additionally or alternatively, locally non-uniform permeation can be reduced, i.e., the second layer and the conductor track layer disposed thereon are more uniformly permeated. In this way, damage to the conductor track layer disposed thereon due to permeation effects can be significantly reduced, and the sensor element formed by the diaphragm structure can achieve significantly better long-term stability and measurement accuracy.
[0031] In an exemplary refinement of the aforementioned configuration of the diaphragm device, the first layer has a thickness of 10 nm to 500 nm, in particular a thickness between 20 nm and 200 nm. With such a layer thickness, the effects and advantages associated with the first layer described in the previous section can be particularly effectively achieved, as already explained in connection with the preceding other exemplary configurations having an even larger layer thickness range. Furthermore, the narrower layer thickness range defined here can exhibit additional advantageous properties that become apparent only in connection with the conductor track layer. As already explained, so-called laser trimming is known from the prior art. In the context of this specification, this method is used to manipulate the conductor tracks of the conductor track layer. For example, if a Wheatstone bridge is formed in the conductor track layer by interconnecting resistor tracks, the resistance value of each resistor track can be precisely adjusted by laser trimming by introducing so-called trim cuts into the resistor tracks with a laser beam. In this method, part of the laser beam usually also strikes the layer below the conductor track layer. Materials that can be used as permeation barriers and insulating layers for the second layer are generally transparent to laser beams, especially SiO2 (silicon dioxide). Thus, a portion of the laser beam impinges on the underlying first layer. If the first layer has a thickness according to this refinement, the first layer can be effectively prevented from being heated by the laser beam and from being damaged as a result of the intense heating. Instead, the heat introduced by the laser beam can be effectively dissipated to the substrate, i.e., the diaphragm section, underneath the first layer. In this way, the diaphragm section functions as a heat sink. On the other hand, if the first layer is too thick, the heat cannot be dissipated quickly enough, resulting in damage to the first layer. Also, if the first layer is too thin, the desired effect of the first layer, particularly the effective reduction of thermal stress and / or intrinsic stress, will not be fully achieved.
[0032] In a further exemplary refinement of the above-described configuration of the diaphragm device, the diaphragm device comprises a protective layer that is applied directly or indirectly to the conductor track layer and at least partially covers the conductor track layer. As a result, the conductor track layer can be effectively protected from damage. In this case, individual surface portions can be left free from the protective layer, for example, to provide access to contact surfaces for electrical contact of the conductor track layer. The protective layer can be, for example, a lacquer or passivation layer that is applied to the conductor track layer by thin-film technology.
[0033] In an exemplary configuration of the diaphragm device, the process medium mentioned in the previous section, or at least a component of the process medium mentioned, is hydrogen, particularly gaseous hydrogen. This element is an important component of many industrial processes. Diaphragm devices known from the prior art can be adversely affected by hydrogen permeation, especially by locally uneven permeation. For example, if such a diaphragm device forms a sensor element, the measurement circuit of this sensor element formed by the conductor track layer can be detuned or altered by permeation effects, threatening measurement accuracy and signal stability in the long term. According to this exemplary configuration of the diaphragm device, the second layer has a lower permeability to hydrogen molecules than the corresponding permeability of the flexible diaphragm section. In combination with the first layer, which effectively reduces various forms of undesirable mechanical stresses (i.e., for example, thermal stresses and / or intrinsic stresses) in the second layer and thus counteracts the formation of microcracks and other damage, the second layer can optimally exert its barrier effect against hydrogen permeation.
[0034] In a further exemplary configuration of the diaphragm device, the material comprising the second layer or a sub-layer included in the second layer has the formula Al x Si y (O,N) 1-x-ywhere x and y are atomic fractions between 0 and 1 and always sum to less than or equal to 1. Here, Si, Al, O, and N represent the chemical elements silicon, aluminum, oxygen, and nitrogen. The (O,N) notation in this formula means that either oxygen or nitrogen is part of the compound. Materials or groups of materials corresponding to this formula have very low permeability compared to many other substances and are therefore particularly suitable for use in the second layer of diaphragm devices. In applications where the process medium is hydrogen or hydrogen is a component of the process medium and it is desirable to prevent hydrogen from permeating the layer structure, silicon dioxide (SiO2), for example, can be used particularly advantageously due to its low permeability to hydrogen and its already well-established and therefore cost-effective use in thin-film technology.
[0035] In a further exemplary configuration of the diaphragm device, the material from which the flexible diaphragm section is made is special steel, in particular austenitic steel, or special alloys, in particular Elgiloy, Hastelloy, 316L or 1.4404. These materials are characterized by high mechanical and / or chemical resistance and can therefore be advantageously used in diaphragm devices in which the first side of the diaphragm device comes into contact with high-temperature and / or high-pressure or chemically and / or mechanically abrasive process media.
[0036] In a further exemplary configuration of the diaphragm device, the material comprising the first layer or at least one sub-layer contained in the first layer has a structure represented by the formula M x N y O z C 1-x-y-zwhere x, y, and z are atomic fractions between 0 and 1 and always equal or less than 1 in total. The symbols N, O, and C represent the chemical elements nitrogen, oxygen, and carbon. The symbol M represents the elements aluminum (Al), chromium (Cr), titanium (Ti), molybdenum (Mo), tungsten (W), hafnium (Hf), and zirconium (Zr). The material group thus defined is particularly suitable for use as the first layer because it can satisfy at least the thermal expansion coefficient requirements for many combinations of materials for the diaphragm section and the second layer. This is especially true when the materials for the flexible diaphragm section and the second layer are each selected from the aforementioned material group. The appropriate selection can be made based on literature values or experimental measurements.
[0037] Alternatively, the material constituting the first layer or at least one sublayer contained therein may be any of the metals with the chemical element symbols Be, Sc, Ti, V, Cr, Fe, Ge, Zr, Nb, Mo, Ru, Rh, Pd, Ce, Pr, Nd, Pm, Gd, Tb, Dy, Ho, Lu, Hf, Ta, W, Re, Os, Ir, Pt, or Th, or any of the materials with the chemical bond symbols Si3N4, SiC, TiN, TiC, AlN, Al2O3, ZrO2, BaTiO3, Cr2O3, TiAlN, or ZrN. These materials are particularly suitable for the first layer because they can satisfy at least the thermal expansion coefficient requirements for many material combinations of the diaphragm section and the second layer. This is particularly true when the materials for the flexible diaphragm section and the second layer are selected from the aforementioned group of materials. The appropriate selection can be based on literature values or experimental measurements. The use of titanium or titanium nitride is particularly preferred, as these materials are also suitable, for example, as anchoring layers, especially when the aforementioned special alloys are used for the flexible diaphragm section.
[0038] Another aspect of the invention relates to a pressure gauge including a diaphragm arrangement according to the first aspect of the invention or one of the exemplary configurations or modifications of the diaphragm arrangement described above.
[0039] Another aspect of the present invention relates to a pressure sensor including a diaphragm device according to the first aspect of the present invention or one of the exemplary configurations or improvements of the diaphragm device mentioned above. Preferably, the diaphragm device of the pressure sensor comprises a flexible diaphragm section made of special steel or a special alloy, a first layer made of titanium or titanium nitride, and a second layer made of silicon dioxide. This material selection allows the advantages of the present invention and its exemplary configurations described in the previous section to be particularly effectively realized, while at the same time allowing the layer structure to be inexpensively and efficiently manufactured using thin-film technology. Furthermore, the pressure sensor includes a conductor track layer disposed indirectly or directly on the second layer. This can form a measurement bridge that converts local strain or stretch on the surface of the flexible diaphragm section into a measurable electrical variable. The layer structure effectively protects this conductor track layer from damaging effects due to penetration of the process medium or at least one component of the process medium. The pressure sensor is particularly advantageously suitable for use with hydrogen or hydrogen-containing process media as a process medium, particularly in the exemplary material combinations described above, and can prevent or at least significantly reduce hydrogen permeation through the layer structure.
[0040] Thus, another aspect of the present invention includes the use of a diaphragm apparatus according to the first aspect of the invention, or one of the exemplary configurations or refinements of a diaphragm apparatus, pressure gauge and / or pressure sensor according to the further-mentioned aspects of the invention, with or for a process medium that is or contains hydrogen. When used in such hydrogen applications, the effects, operations and advantages of the various aspects, configurations and refinements of the present invention set out in the previous section can be used to particular advantage.
[0041] The disclosure of this specification is not limited to the above examples, but also includes all combinations thereof, unless they are logically mutually exclusive. [Brief explanation of the drawings]
[0042] Exemplary configurations and embodiments of the present invention are described in more detail below with reference to the drawings. [Figure 1] 1 shows a schematic cross-sectional view of a diaphragm device. [Figure 2] 1 shows a schematic cross-sectional view of a diaphragm device. [Figure 3] 1 shows a cross-sectional view of a pressure sensor with a diaphragm arrangement. [Figure 4A] 1 shows a perspective view of a pressure sensor with a diaphragm arrangement. [Figure 4B] 1 shows a cross-sectional view of a pressure sensor with a diaphragm arrangement. [Figure 5] 1 shows a schematic cross-sectional view of a pressure measuring device with a pressure sensor.
[0043] Corresponding elements are designated by the same reference numerals in all figures.
[0044] Detailed Description of the Drawings 1 and 2 show a diaphragm device 100 with a portion of a flexible diaphragm section 110. A layer structure 120 having a first layer 121 and a second layer 122 is arranged on a second side 112 of the diaphragm section 110. The first side 111 of the diaphragm section 110 may be exposed to a process medium 200 in a manner not shown in detail.
[0045] In FIG. 2, the first layer 121 and the second layer 122 in each case comprise a number of sub-layers 121′, 121″, 121′”, 122′, 122″, 122′″.
[0046] 3, 4A and 4B show in each case a pressure sensor 400 comprising a diaphragm device 100. In this case, the pressure sensor 400 is made in the form of a pressure-measuring capsule. A strong, rigid edge area 410 in the form of a hollow cylinder supports the flexible diaphragm section 110.
[0047] 3 shows the layer structure 120 in more detail in a cross section. A conductor track layer 123 is applied to the second layer 122, on which in turn a protective layer 124 is applied.
[0048] FIG. 5 is a schematic cross-sectional view of a pressure measuring device 500. It comprises a connection part 510 and a measuring device housing 520. Via the connection part 510, the pressure measuring device 500 is connected to a measurement connection 610 of a process installation 600, for example, via a screw connection. The connection part 510 has an access opening 511 through which the process medium 200 from the process installation 600 is supplied to the pressure sensor 400. In this case, the pressure sensor 400 may be configured according to FIGS. 4A and 4B. The pressure sensor 400 comprises a flexible diaphragm section 110 with a layer structure 120, which is formed, for example, according to the embodiment of FIG. 3. A measuring bridge with a piezoresistive track is formed in a conductor track layer 123 of the layer structure 120, which enables metrological detection of deformation of the diaphragm section 110 due to the process medium 200 contacting the first side 111 of the diaphragm section 110. The conductor track layer 123 is connected by means of schematically shown lines, for example so-called bonding wires, to the schematically shown evaluation electronics 530 of the pressure measuring device 500, which measures the electrical properties of the measuring bridge and derives therefrom the measured value, in particular the pressure of the process medium 200. A measured value signal representing this measured value is provided via a communication interface 540, for example via a plug socket with electronic contacts or as a wireless signal.
[0049] The present invention is not limited to the preceding embodiments, but can be modified within the scope of the following claims. Likewise, individual aspects from the dependent claims can be combined with one another, unless they are logically mutually exclusive. [Explanation of symbols]
[0050] 100 Diaphragm device 110 Diaphragm division 111 first side of diaphragm section 112 second side of diaphragm section 120 layer structure 121 First Layer 121',121'',121''' Sublayer of the first layer 122 Second Layer 122',122'',122''' Second layer sublayer 123 Conductor layer 124 Protective layer 200 Process Media 300 Pressure Gauge 400 Pressure Sensor 410 Edge Region 500 Pressure Measuring Device 510 Connection part 511 Access opening 520 Measuring device housing 530 Evaluation Electronic Equipment 540 Communication Interface 600 Process Equipment 610 Measurement Connection
Claims
1. A diaphragm device (100) comprising a flexible diaphragm section (110), wherein a first side (111) of the diaphragm section is exposed to or configured to be exposed to a process medium (200), and a second side (112) of the diaphragm section has a layered structure (120), in the diaphragm device (100), The layer structure (120) comprises at least a first layer (121) and a second layer (122), - The first layer has a coefficient of thermal expansion that is between the value of the coefficient of thermal expansion of the diaphragm section (110) and the value of the coefficient of thermal expansion of the second layer (122). - The second layer (122) has a transmittance lower than the corresponding transmittance of the diaphragm section (110) with respect to the process medium (200) or components of the process medium (200). - The first layer (121) is directly or indirectly attached to the diaphragm section (110), and the second layer (122) is directly or indirectly attached to the first layer (121). A diaphragm device (100) characterized by the following features.
2. The transmittance of the second layer (122) or the sublayers (122', 122'', 122'''') contained in the second layer (122) to the process medium (200) or the components of the process medium (200) is at least a coefficient of 100, preferably at least a coefficient of 1000, and particularly preferably at least a coefficient of 100, compared to the corresponding transmittance of the diaphragm section (110). ６ The diaphragm device (100) according to claim 1, which is only lower.
3. The first layer (121) or the sublayers (121', 121'', 121'''') contained in the first layer (121) have structural constants that are between the same structural constant values of the diaphragm section (110) and the second layer (122). The aforementioned structure constant is, in particular, the lattice constant or the average interatomic distance. The diaphragm device (100) according to claim 1 or 2.
4. The first layer (121) or the sublayers (121', 121'', 121'''') contained in the first layer (121) have a transmittance lower than the corresponding transmittance of the diaphragm section (110) with respect to the process medium (200) or the components of the process medium (200). The transmittance of the first layer (121) or the sublayers (121', 121'', 121'''') contained in the first layer (121) to the process medium (200) or the components of the process medium (200) is, in particular, at least a coefficient of 100, preferably at least a coefficient of 1000, and especially preferably at least a coefficient of 100, compared to the corresponding transmittance of the diaphragm section (110) and / or the corresponding transmittance of the second layer (122). ６ Only low, The diaphragm device (100) according to claim 1 or 2.
5. The first layer (121) or the sublayers (121', 121'', 121'''') contained in the first layer (121) have a transmittance higher than the corresponding transmittance of the diaphragm section (110) with respect to the process medium (200) or the components of the process medium (200). The transmittance of the first layer (121) or the sublayers (121', 121'', 121'''') contained in the first layer (121) to the process medium (200) or the components of the process medium (200) is, in particular, at least a coefficient of 100, preferably at least a coefficient of 1000, and especially preferably at least a coefficient of 100, compared to the corresponding transmittance of the diaphragm section (110) and / or the corresponding transmittance of the second layer (122). ６ Only expensive, The diaphragm device (100) according to claim 1 or 2.
6. The first layer (121) comprises at least two sublayers (121', 121'', 121'''), and the thermal expansion coefficients of the at least two sublayers (121', 121'', 121''') are between the thermal expansion coefficients of the diaphragm section (110) and the second layer (122). The sub-layers (121', 121'', 121'''') are sequentially attached to the diaphragm section (110) such that the difference between the thermal expansion coefficient of the sub-layer (121') closest to the second side (112) of the diaphragm section and the thermal expansion coefficient of the diaphragm section is smallest, and the difference between the thermal expansion coefficient of each subsequent sub-layer (121'', 121'''') and the thermal expansion coefficient of the diaphragm section (110) is larger than that of the preceding sub-layer. The diaphragm device (100) according to claim 1 or 2.
7. The diaphragm device (100) according to claim 1 or 2, wherein the first layer (121) has a thickness of 10 nm to 5000 nm, particularly 10 nm to 500 nm, and particularly 20 nm to 200 nm.
8. The diaphragm device (100) according to claim 1 or 2, wherein the second layer (122) or the sublayers (121', 121'', 121'''') contained in the second layer (122) have an electrical resistance greater than 10 MOhm, and more particularly greater than 100 MOhm.
9. - A conductor path layer (123) directly or indirectly attached to the second layer (122), - A protective layer (124) that is directly or indirectly attached to the conductor path layer (123) and covers the conductor path layer (123) at least partially. A diaphragm device (100) according to claim 1 or 2, characterized by comprising the above.
10. The diaphragm device (100) according to claim 1 or 2, wherein the process medium (200) or a component of the process medium (200) is hydrogen.
11. The material constituting the second layer (122) or the sublayers (122', 122'', 122'''') contained in the second layer (122) is a material of formula Al ｘ Si ｙ (O, N) １－ｘ－ｙ It is expressed as, in the formula, - x and y are atomic fractions between 0 and 1, and their sum is always less than or equal to 1. - Si is silicon, - Al stands for aluminum, - O is oxygen, - N is nitrogen. The diaphragm device (100) according to claim 1 or 2.
12. The material constituting the diaphragm section (110) is - Special steels, especially austenitic steels, or - Special alloys, especially Elgiloy, Hastelloy, 316L, or 1.4404. The diaphragm device (100) according to claim 1 or 2.
13. The material constituting the first layer (121) or the sublayers (121', 121'', 121'''') contained in the first layer (121) is represented by the formula MxNyOzC1-x-y-z, where, - x, y, and z are atomic fractions between 0 and 1, and their sum is always less than or equal to 1. - N is nitrogen, - O is oxygen, - C is carbon, - M is one of the following elements: Al, Cr, Ti, Mo, W, Hf, or Zr. And / or the material constituting the first layer (121) or the sublayers (121', 121'', 121'''') included in the first layer (121) is - One of the following metals: Be, Sc, Ti, V, Cr, Fe, Ge, Zr, Nb, Mo, Ru, Rh, Pd, Ce, Pr, Nd, Pm, Gd, Tb, Dy, Ho, Lu, Hf, Ta, W, Re, Os, Ir, Pt, or Th, or - Fe-C alloy, Ni-based alloy, special steel, Ti alloy or Kovar, - It is one of the following: Si3N4, SiC, TiN, TiC, AlN, Al2O3, ZrO2, BaTiO3, Cr2O3, TiAlN, or ZrN. The diaphragm device (100) according to claim 1 or 2.
14. A pressure sensor (400) comprising a diaphragm device (100) according to claim 1 or 2.
15. Use of the diaphragm apparatus (100) according to claim 1 or 2 with respect to hydrogen or a hydrogen-containing process medium (200), wherein the second layer (122) and / or the first layer (121) have a lower transmittance to hydrogen than the corresponding transmittance of the diaphragm section (110).