CORROSION PROTECTION ELEMENT FOR A FIELD DEVICE

Description

[0001] The invention relates to a corrosion protection for a field device, which comprises at least one component made of stainless steel, in particular austenitic stainless steel, which is in contact with an environment of the field device, and to a field device equipped with at least one such corrosion protection element.

[0002] Field devices are used in industrial measurement technology, especially in process and automation technology, for the metrological acquisition of process-relevant measured variables. These field devices include sensors, transmitters, transducers, and various types of measuring instruments used for the metrological acquisition, measurement, and / or monitoring of measured variables.

[0003] Field devices include, among other things, differential pressure sensors, as described, for example, in DE 103 47 861 A1. These sensors comprise a measuring element that is clamped between two flanges arranged on opposite outer sides of a measuring element body. For this purpose, the flanges are connected to one another by screws, each of which has an exposed area between the flanges that is in contact with the surroundings of the measuring element. In addition, these sensors comprise a differential pressure sensor, which can be subjected to one of the two pressures whose difference is to be measured via two diaphragm seals connected upstream of the sensor. The diaphragm seals are each sealed off from the outside by a separating diaphragm welded to an outer side of the measuring element body.The pressure is applied to the separating membranes via a pressure transmission channel that can be connected to a differential pressure line and that leads through the respective flange to a pressure chamber enclosed beneath the flange and adjacent to the respective separating membrane.

[0004] Just like many other field devices, differential pressure sensors can be exposed to comparatively high mechanical stress during operation. For example, diaphragm seals, like pressure or differential pressure sensors, may be exposed to very high pressures that must be transmitted or measured. Depending on the application, differential pressure sensors may also have to withstand very high static pressures superimposed on the differential pressure to be measured. Furthermore, they should, if possible, withstand one-sided pressure overloads, such as overloads of up to 200 bar or even up to 650 bar.

[0005] Today, a high level of mechanical resistance of field devices is usually achieved by at least protecting their mechanically highly stressed components, such as

[0006] Housings, process connections, fasteners, measuring element bodies, etc., are made of pressure-resistant, mechanically stable metals. Stainless steels are particularly suitable for this purpose. Austenitic stainless steels offer the additional advantage of a certain ductility, which protects the components made from them from stress cracks, especially in the event of sudden overloads. Austenitic stainless steels are also used today, among other things, for the production of separating diaphragms for diaphragm seals.

[0007] There are applications in which field devices are exposed to a corrosive environment which can cause corrosion to attack stainless steel components that come into contact with them. These include humid, saline environments such as those found in offshore plants or in plants that use seawater or other liquids containing salt and / or chloride, particularly those operated at high temperatures. These environments can cause corrosion to attack components made of austenitic stainless steel, for example. Corrosive environments cause pitting corrosion. In addition, in field devices that have narrow gaps that come into contact with the corrosive environment, they lead to crevice corrosion and attack weld seams. For example, in the differential pressure sensors mentioned above, the flanges that are in contact with the environment and the measuring element that is in contact with the environment can be attacked by pitting corrosion.Furthermore, external crevice corrosion can cause the corrosive environment to penetrate between one of the flanges and the measuring element, possibly even reaching the respective pressure chamber, where it comes into contact with the separating diaphragm and the weld connecting the separating diaphragm to the measuring element. Over time, this can lead to leaks in the pressure chambers and / or the diaphragm seals, which can result in significant consequential damage depending on the location.

[0008] As the example shows, corrosion of stainless steel components can cause significant damage to the field device and, under certain circumstances, even lead to total failure. Accordingly, field devices containing stainless steel components should not be used in corrosive environments that could corrode the stainless steel used.

[0009] To achieve greater corrosion resistance, field device components exposed to corrosive environments can be manufactured from more corrosion-resistant duplex or super-duplex steels. However, these materials are more expensive than austenitic stainless steel grades and significantly more difficult to machine. The latter leads to comparatively high production costs, especially for components that require turning.

[0010] It is an object of the invention to provide a reliable, easily deployable, and cost-effective corrosion protection for field devices. Prior art document DE 25 48 377 A1 deals with a corrosion protection element with a clamping point. However, the field device must be inserted lengthwise from one of its ends.

[0011] For this purpose, the invention comprises a corrosion protection element according to claim 1.

[0012] Corrosion protection elements according to the invention offer the advantage that high-quality cathodic corrosion protection of components made of stainless steel, in particular austenitic stainless steel, can be achieved by sacrificial anodes comprising iron and / or rusting steel. In addition, they offer the advantage that they not only protect the component to which they are attached, but at the same time also provide cathodic corrosion protection for all other components of the field device that are made of stainless steel or another metal that is more noble than iron or rusting steel and that are in electrically conductive contact with the corrosion protection element and / or the component equipped with the corrosion protection element. This also makes it possible to protect components to which, for example, no corrosion protection element can be attached due to space constraints. This includes in particularalso components that are adjacent to narrow gaps in the field device that may come into contact with the corrosive environment at the location where the field device is used.

[0013] Furthermore, iron and stainless steel are inexpensive, easy-to-machine materials from which bodies with a very wide range of shapes can be manufactured. This offers the advantage that the shape of the corrosion protection elements according to the invention can be easily adapted to the shape of the components present in the field device. This allows existing or even already deployed field devices to be retrofitted with corrosion protection elements according to the invention and / or to replace worn-out corrosion protection elements after their use on a component of a field device.

[0014] A first further development is characterized by the fact that the corrosion protection element is designed as an element that can be pushed, plugged or clamped onto the component.

[0015] A second further development is characterized in that the corrosion protection element comprises a body, in particular a one-piece body, made of iron or rusting steel.

[0016] A third further development is characterized by the fact that the body is coated with a coating material suitable for cathodic corrosion protection of stainless steel.

[0017] A further development of the third further development is characterized by the fact that the coating material includes zinc.

[0018] Further training courses of the third level or their further training are characterized by the fact that the body has a material thickness in the order of 0.2 mm to 3 mm, in particular 0.3 mm to 1 mm, and / or the coating has a layer thickness in the order of 20 µm to 50 µm.

[0019] A fourth development is characterized in that the corrosion protection element comprises a sleeve that can be pushed onto the component, wherein the corrosion protection element is designed in particular as a one-piece, sleeve-shaped element that can be pushed onto the component.

[0020] A fifth development is characterized in that the corrosion protection element comprises a spring clamp that can be plugged or clamped onto the component, wherein the corrosion protection element is designed in particular as a one-piece, spring clamp-shaped corrosion protection element (3) that can be plugged or clamped onto the component.

[0021] Furthermore, the invention comprises a field device equipped with at least one corrosion protection element according to the invention, which is characterized in that each provided corrosion protection element is mounted on a component of the field device made of stainless steel, in particular austenitic stainless steel, which is in contact with an environment of the field device.

[0022] A first development of the field device is characterized by the fact that the intended corrosion protection elements comprise at least one corrosion protection element comprising a sleeve or designed as a sleeve-shaped corrosion protection element, which is pushed onto an elongated component and surrounds at least one area of ​​this component on the outside, and / or comprise at least one corrosion protection element which is pushed or clamped onto an externally accessible component and which comprises a spring clip or is designed as a one-piece spring-clamp-shaped corrosion protection element, the two spring legs of which encompass at least one area of ​​this component.

[0023] A further development of the latter development is characterized in that a limitation is provided on both sides of the area of ​​at least one of the components, which limitation is designed such that it limits an axial movement of the corrosion protection element attached to the area in a direction parallel to the longitudinal axis of the area.

[0024] A second development of the field device is characterized in that at least one of the provided components has a tapered region onto which a corrosion protection element comprising a spring clamp or designed as a one-piece, spring clamp-shaped corrosion protection element is plugged or clamped in such a way that it encompasses the tapered region on the outside.

[0025] A third development of the field device is characterized in that the field device comprises at least one further component made of stainless steel, in particular austenitic stainless steel, or a metal that is more noble than iron or rusting steel, which is protected against corrosion by at least one of the provided corrosion protection elements and which is in electrically conductive contact with at least one of the components equipped with one of the corrosion protection elements and / or the corrosion protection element mounted on the respective component.

[0026] A fourth development of the field device is characterized by the fact that the the field device comprises a differential pressure sensor, the differential pressure sensor comprises a measuring mechanism clamped between two flanges connected to one another by screws, the screws each comprise an area exposed between the flanges which is in contact with the environment, and on the area of ​​at least one of the screws which is in contact with the environment, one of the intended corrosion protection elements is attached.

[0027] A fifth further development of the field device for the metrological recording, measurement and / or monitoring of a measured variable of a filling material in a container is characterized by the fact that the field device comprises a part to be arranged inside the container and a part to be arranged outside the container, at least one of the two parts comprises a component, in particular a housing, on which a corrosion protection element is attached, wherein the corrosion protection element is in particular a corrosion protection element plugged or clamped onto a tapered housing section of the respective housing.

[0028] The invention and further advantages will now be explained in more detail with reference to the figures of the drawing, which illustrate two exemplary embodiments. Identical elements are provided with the same reference numerals in the figures. Fig. 1 shows: a corrosion protection element designed as a sleeve; Fig. 2 shows: a view of a corrosion protection element designed as a spring clip; Fig. 3 shows: the corrosion protection element of Fig. 2in section; Fig. 4 shows: a view of a differential pressure sensor; Fig. 5 shows: a differential pressure sensor in section; Fig. 6 shows: a flange and the screws of a differential pressure sensor together with sleeve-shaped corrosion protection elements pushed onto the screws; Fig. 7 shows: a view of a differential pressure sensor together with spring-clip-shaped corrosion protection elements pushed or clamped onto its screws; and Fig. 8 shows: a level limit switch.

[0029] The invention encompasses corrosion protection elements for field devices that comprise at least one stainless steel component in contact with the environment of the field device. Corrosion protection elements according to the invention are characterized in that they are each designed as a sacrificial anode comprising iron or rusting steel and have a shape that allows the respective corrosion protection element to be attached to the component of the field device in such a way that the sacrificial anode is in electrically conductive contact with the component.

[0030] With regard to the electrically conductive contact, it is sufficient if the sacrificial anode and the component to which the corrosion protection element is attached touch at least at one point.

[0031] Iron and stainless steel are less noble materials than stainless steel in terms of the electrochemical series. When used in a corrosive environment, the corrosion protection element attached to the field device component forms part of a primary element, which includes the sacrificial anode as the anode and the component made of stainless steel, which is more noble than iron or stainless steel, as the cathode. Attaching the corrosion protection element to the component thus achieves cathodic corrosion protection of the component, which lasts until the sacrificial anode is consumed by corrosion.

[0032] This cathodic corrosion protection also extends to any other component of the field device that may come into contact with the corrosive environment and that is made of stainless steel or another metal that is more noble than iron or rusting steel and is in electrically conductive contact with the sacrificial anode and / or the component.

[0033] This provides high-quality corrosion protection, particularly for components and any other components of the field device made of austenitic stainless steel, such as the austenitic stainless steel known under the material designation 304 or the austenitic stainless steel known under the material designation 316L.

[0034] In order to ensure that installation is as simple as possible, the corrosion protection elements are preferably designed as elements that can be pushed, plugged or clamped onto the component of the field device.

[0035] Fig. 1shows an embodiment of a corrosion protection element 1 according to the invention, which comprises a sleeve that can be pushed onto a component of a field device. These corrosion protection elements 1 are preferably designed as one-piece, sleeve-shaped elements that can be pushed onto the component. This offers the advantage that they can be manufactured cost-effectively from a tube made of iron or stainless steel.

[0036] Alternatively, corrosion protection elements according to the invention can comprise a spring clip that can be plugged or clamped onto the component. This embodiment offers the advantage that the spring clip can be plugged or clamped onto an externally accessible component of a field device without at least one end of the component having to be freely accessible for this purpose. This not only facilitates the attachment and replacement of the corrosion protection element, but also the retrofitting of existing field devices, possibly even those already in use, with these corrosion protection elements.

[0037] Fig. 2 shows a view of an embodiment of such a corrosion protection element 3. Fig. 3 shows the corrosion protection element 3 of Fig. 2 on average. As can be seen from Fig. 3As can be seen, the spring clip comprises two spring legs 5, which are shaped such that they can be opened wide enough to allow the corrosion protection element 3 to be pushed or clamped onto the component. Corrosion protection elements 3 comprising a spring clip can be designed as a clip that can be pushed onto the component or a region of the component from the outside. In this case, the spring legs 5 encompass the region of the component to which they are pushed. Alternatively, they can be designed as a clampable spring, between whose spring legs the component or a region of the component is clamped in the clamped state.

[0038] Corrosion protection elements 3 comprising a spring clip are designed as one-piece, spring-clip-shaped elements. An outward-facing extension 7 is molded onto the free ends of the spring legs 5, facilitating the manual attachment and removal of the corrosion protection element 3.

[0039] One-piece, spring-clamp-shaped corrosion protection elements 3 offer the advantage that they can be produced in a simple and cost-effective manner by punching and bending from a sheet of iron or rusting steel.

[0040] Alternatively, instead of the Fig. 1 to 3 The single-piece corrosion protection elements 1, 3 shown here, but also multi-piece corrosion protection elements, can be used. An example of this are corrosion protection elements that comprise a multi-piece spring clamp, which comprises rigid or spring-elastic spring legs connected to one another by means of a tension spring.

[0041] Corrosion protection elements 1, 3 according to the invention can be made entirely of iron or stainless steel. However, they preferably comprise a body 9, 11 made of iron or stainless steel, which has the shape of the corrosion protection element 1, 3 and onto which a coating 13, 15 made of a coating material suitable for cathodic corrosion protection of the component and any other components present is applied.

[0042] This variant offers the advantage that the coating material can be selected essentially independently of the requirements for the mechanical properties of the corrosion protection element 1, 3 or the body 9, 11.

[0043] Zinc or a zinc-containing material is preferably used as the coating material. This coating material can be applied, for example, by electroplating or by immersing the body 9, 11 in a zinc melt.

[0044] The coatings 13, 15 preferably have a layer thickness in the range of 20 µm to 50 µm. This comparatively thin layer thickness also allows the use of comparatively brittle coating materials, such as zinc or zinc-containing materials. In comparison, the body 9, 11, which determines the mechanical properties of the respective corrosion protection element 1, 3, preferably has a material thickness in the range of 0.2 mm to 3 mm, in particular 0.2 mm to 1 mm. Depending on the design and application, bodies with a greater material thickness and / or coatings with a greater layer thickness can also be used.

[0045] When coated corrosion protection elements 1, 3 are used, the coating 13, 15 is initially attacked and corroded away. This protects the component to which the corrosion protection element 1, 3 is attached, as well as any other components of the field device that are connected to the cathode in the redox process, from corrosion. As soon as the coating 13, 15 is completely consumed, another anodic reaction begins, in which the body 9, 11 is oxidized. This creates rust-like oxidation products. During this stage, the component, as well as any other components present, are protected from corrosion by the body 9, 11. This protection lasts until the body 9, 11 is also consumed or corroded away or completely corroded.

[0046] The coating 13, 15 offers the advantage that new corrosion protection elements 1, 3 can be identified as such by the coating 13, 15. Furthermore, galvanized corrosion protection elements 1, 3 do not rust during storage. This not only makes new corrosion protection elements 1, 3 more visually appealing, but also facilitates their storage.

[0047] Coated corrosion protection elements 1, 3 offer the further advantage that the absence of the coating 13, 15 worn away by corrosion, as well as the formation of the externally visible reaction products resulting from oxidation of the body 9, 11, such as reddish rust, are indicators that show that the corrosion protection element 1, 3 has been exposed to a corrosive environment.

[0048] The condition of a corrosion protection element 1, 3 in use is preferably checked regularly and the corrosion protection element 1, 3 is replaced if necessary.

[0049] In addition to the corrosion protection elements 1, 3, the invention also encompasses field devices that comprise at least one stainless steel component equipped with a corrosion protection element 1, 3 according to the invention and in contact with the environment. The respective component is preferably a component already present in the field device. Particularly suitable for this purpose are components that are not only in contact with the environment but are also visible from the outside. The latter offers the advantage that the condition of the corrosion protection element 1, 3 attached to it can be visually inspected at any time.

[0050] Field devices can, for example, comprise at least one elongate component having an elongate region onto which a corrosion protection element 1 comprising a sleeve is pushed. In this case, the field device preferably comprises two limits arranged at both ends of the elongate region, which limits are designed such that they limit axial movement of the corrosion protection element 1 pushed onto the region in a direction parallel to the longitudinal axis of the component. In this variant, the corrosion protection element 1 is attached before the second limit is provided. Preferably, at least one of the two limits is designed as a removable limit. This offers the advantage that the corrosion protection element 1 can be replaced if necessary by dismantling the limit, replacing the corrosion protection element 1 and then reassembling the limit.

[0051] Alternatively or additionally, the field device can comprise at least one externally accessible component which has an area onto which a corrosion protection element 3 comprising a spring clip is plugged or clamped. If the corrosion protection element 3 is plugged in, the field device in this embodiment also preferably has two limits arranged on either side of the area, which limit axial movement of the corrosion protection element 3 plugged onto the area in a direction parallel to the longitudinal axis of the area. Since none of these limits has to be removed to replace the corrosion protection element 3, the limit can also be provided by the component itself. For example, the component can comprise a tapered area onto which the corrosion protection element 3 is plugged or clamped.A tapered area is defined here as an area whose cross-sectional area is smaller than the cross-sectional areas of the areas adjacent to it on both sides, each forming one of the two boundaries.

[0052] If a corrosion protection element 1, 3 according to the invention is fastened to the component by clamping, for example with an appropriate dimensioning of the spring force of the spring clamp, or is fixed or held on the component in another way, e.g. held by gravity, these limitations can be dispensed with.

[0053] Corrosion protection elements 3 that include or are designed as spring clips offer the advantage of being externally mounted and subsequently replaced at any time. For this purpose, only the area where the corrosion protection element 3 is or will be mounted must be accessible from the outside. This does not require the field device to be removed from the installation site, nor is it necessary to dismantle any of the provided barriers.

[0054] Fig. 4 shows a view and Fig. 5A sectional drawing of a first exemplary embodiment of a field device equipped with at least one corrosion protection element 1, 3. The field device shown here as an example is a differential pressure sensor. The sensor comprises a measuring element 17, which is clamped between two flanges 19 arranged on opposite outer sides of a measuring element body of the measuring element 17. For this purpose, the flanges 19 are connected to one another by screws 21, each of which has an area exposed between the flanges 19 and in contact with the surroundings of the measuring element. In addition, the measuring element comprises a differential pressure sensor 23, which can be subjected to one of the two pressures, the difference between which is to be measured, via two diaphragm seals 25 connected upstream of the sensor.The diaphragm seals 25 are each sealed off from the outside by a separating diaphragm 27 welded to the outside of the measuring element body and filled with a pressure-transmitting fluid. The separating diaphragms 27 are pressurized via a pressure transmission channel 29 that can be connected to a differential pressure line and leads through the respective flange 19 to a pressure chamber 31 enclosed beneath the respective flange 19 and adjacent to the respective separating diaphragm 27.

[0055] In this field device, the screws 21, as well as preferably also the flanges 19, the measuring element body of the measuring element 17 and the separating membranes 27 are made of stainless steel, preferably austenitic stainless steel.

[0056] In this embodiment, preferably at least one of the screws 21 forms a component of the field device to which a corrosion protection element 1, 3 according to the invention is attached.

[0057] Fig. 6shows one of the essentially disc-shaped flanges 19 of a differential pressure sensor, through whose four openings provided in its corners one of the screws 21 is inserted. Each of these screws 21 has an area exposed in the field device between the two flanges 19, onto which one of the Fig. 3 shown corrosion protection elements 1 comprising a sleeve to the in Fig. 6 The differential pressure sensor is manufactured from the assembly equipped with the corrosion protection elements 1, in which the measuring element 17 and the second flange 19 are mounted on the Fig. 6shown flange 19 and the two flanges 19 are connected to each other by means of the screws 21. Subsequently, each of the two flanges 19 forms one of the limits provided in the field device, which limit the axial movement of the sleeve in a direction parallel to the longitudinal axis of the respective component, namely the screw 21.

[0058] Fig. 7 shows a view of another differential pressure sensor, in which the areas of the screws 21 which are exposed between the two flanges 19 and are accessible from the outside are each provided with one of the Fig. 2 and 3 shown corrosion protection elements 3 designed as spring clamps.

[0059] The use of at least one of the screws 21 as a component equipped with one of the corrosion protection elements 1, 3 according to the invention offers the advantage that, via each of these corrosion protection elements 1, 3, not only the respective screw 21 but also all other stainless steel components electrically connected to the respective screw 21 and / or the corrosion protection element 1 or 3 attached thereto, namely the flanges 19, the measuring mechanism body, and the separating membranes 27, are protected from corrosion. Furthermore, the weld seams connecting the separating membranes 27 to the measuring mechanism body are also protected from corrosion.

[0060] Fig. 8shows a view of a further embodiment of a field device equipped with at least one corrosion protection element 1, 3 according to the invention. This field device comprises a process connection 33, by means of which it can be inserted into an opening of a container (not shown here) in such a way that a first part A of the field device is arranged outside and a second part B of the field device is arranged inside the container. Such an installation method is common, for example, in measuring devices, measuring sensors or limit switches for the metrological detection, measurement and / or monitoring of a measured variable of a filling material contained in the container, such as a fill level, a density or a conductivity of the filling material. In these field devices, the first part A usually comprises a first housing 35 in which, for example, electronics are housed. The second part B comprises, for exampleAn element exposed during operation to the measured variable to be detected, measured, and / or monitored, such as a sensor or probe, or a transmitting and / or receiving unit, such as an antenna, with which signals are sent toward the medium and / or received after their interaction with the medium. The second part B is exposed to a corrosive environment during use, for example, when it comes into contact with a corrosive medium or a corrosive vapor phase above the medium.

[0061] Fig. 8shows, as an example, a fill level limit switch for detecting and / or monitoring an exceedance or undershoot of a fill level predetermined by the installation height of the limit switch on the container. Fill level limit switches of this type are marketed by the applicant under the product name Liquiphant. Part B of this limit switch, which is to be arranged inside the container, comprises a second housing 37, at the end of which a mechanical structure 39 is arranged that can be excited to oscillate. The second housing 37 and the structure 39 can be connected to one another, for example, via an annular weld seam 41. In the illustrated embodiment, the structure 39 comprises two oscillating rods 43 coupled via a membrane closing off the end of the second housing 37, which oscillate rods can be excited to oscillate in antiphase and perpendicular to their longitudinal axis by means of an electromechanical transducer arranged in the second housing 37. The transducer is connected to, for example, aconnected to electronics arranged in the first and / or second housing 35, 37, which detects and / or monitors an exceedance or undershoot of the fill level specified by the installation height of the limit switch based on at least one property of the resulting oscillation of the structure 39 detected by the transducer, such as its frequency and / or amplitude.

[0062] In this field device, the first housing 35, the second housing 37, the process connection 33, and / or the structure 39 are made of stainless steel, preferably austenitic stainless steel. In this respect, at least one of the housings 35, 37 preferably forms a component of the field device to which a corrosion protection element 1, 3 according to the invention is attached.

[0063] Fig. 8 shows as an example a corrosion protection element 3 which is plugged or clamped onto a housing section of the first housing 35 and which is essentially identical in construction to the one shown in Fig. 2 and 3The corrosion protection element 3 shown here is the first housing 35 and the process connection 33. This protection is particularly advantageous when the housing 35 is used under conditions in a warmer, corrosive environment, such as salt spray, which condenses on the colder housing 35, since the risk of corrosion for stainless steel, especially austenitic stainless steel, is particularly high here.

[0064] If reaction products resulting from corrosion of the corrosion protection elements 1, 3 can be tolerated at the place of use in the container, the second housing 37 located inside the container during operation can alternatively or additionally be equipped with a corrosion protection element 3 according to the invention. Fig. 8 shows a corrosion protection element 3 which is plugged or clamped onto a housing section of the second housing 37 and which is essentially identical in construction to the one shown in Fig. 2 and 3shown corrosion protection element 3. This protects the second housing 37, the structure 39 and the process connection 33, as well as the weld seam 41, from corrosion.

[0065] The two housing sections are preferably each formed as tapered regions of the respective housing 35, 37, each having a cross-sectional area that is smaller than the cross-sectional areas of the two regions of the respective housing 35, 37 adjacent thereto on both sides, each forming one of the previously described boundaries. 1Corrosion protection element 3Corrosion protection element 5Spring leg 7Extension 9Body 11Body 13Coating 15Coating 17Measuring element 19Flange 21Screws 23Differential pressure sensor 25Diaphragm seal 27Separating diaphragm 29Pressure transmission channel 31Pressure chamber 33Process connection 35First housing 37Second housing 39Formwork 41Weld seam 43Oscillating rod

Claims

1. A corrosion protection element (1, 3) for a field device, - wherein the field device comprises a component made from stainless steel, in particular made from austenitic stainless steel, in contact with an environment of the field device, characterized in that - the corrosion protection element (1, 3) is configured as a sacrificial anode comprising iron or oxidizing steel and has a mold environment which is configured such that the corrosion protection element (1, 3) can be attached to the component of the field device such that the sacrificial anode is in electrically conductive contact with the component and that the corrosion protection element (3) is configured as a one-part corrosion protection element (3) in the shape of a spring terminal, which can be attached or clamped onto the component, wherein - the corrosion protection element comprises a spring terminal with two spring spades, wherein an extension pointing outward is molded onto the exposed ends of the spring spades, which makes it easier to manually attach and remove the corrosion protection element.

2. The corrosion protection element as claimed in claim 1, characterized in that the corrosion protection element (1, 3) comprises a body (9, 11), in particular a one-piece body (9, 11), made from iron or an oxidizing steel.

3. The corrosion protection element as claimed in claims 1 and 2, characterized in that the body (9, 11) is coated with a coating (13, 15) consisting of a coating material suitable for the cathodic corrosion protection of stainless steel.

4. The corrosion protection element as claimed in the preceding claim, characterized in that the coating material comprises zinc.

5. The corrosion protection element as claimed in claims 3 and 4, characterized in that - the body (9, 11) has a material thickness in the magnitude of 0.2 mm to 3 mm, in particular of 0.3 mm to 1 mm, and / or - the coating (13, 15) has a layer thickness in the magnitude of 20 µm to 50 µm.

6. A field device equipped with at least one corrosion protection element (1, 3) as claimed in claims 1 to 5, characterized in that each provided corrosion protection element (1, 3) is in each case mounted on a component of the field device made from stainless steel, in particular made from austenitic stainless steel, in contact with an environment of the field device.

7. The field device as claimed in claim 6, characterized in that the provided corrosion protection elements (1, 3) comprise at least one corrosion protection element (3) attached or clamped onto a component that is accessible from the outside, which is configured as a one-piece corrosion protection element (3) in the shape of a spring terminal, the two spring spades of which encompass at least one area of this component.

8. The field device as claimed in claim 7, characterized in that a limit is provided in each case on both sides of the area of at least one of the components, which is configured such that it limits an axial movement of the corrosion protection element (1, 3) attached to the area in the direction running parallel to the longitudinal axis of the area.

9. The field device as claimed in claims 6 to 8, characterized in that at least one of the provided components has a tapered area onto which a one-piece corrosion protection element (3) configured in the shape of a spring terminal is attached or clamped such that it encompasses the outside of the tapered area.

10. The field device as claimed in claims 6 to 9, characterized in that the field device comprises at least one additional component made from stainless steel, in particular from austenitic stainless steel, or a metal more precious than iron or oxidizing steel, protected against corrosion by at least one of the provided corrosion protection elements (1, 3), which is in electrically conductive contact with at least one of the components equipped with one of the corrosion protection elements (1, 3) and / or the corrosion protection element (1, 3) mounted on the respective component.

11. The field device as claimed in claims 6 to 10, characterized in that - the field device comprises a differential pressure flowmeter, - the differential pressure flowmeter comprises a measuring mechanism (17) clamped between two flanges (19) connected to each other by screws (21), - each screw (21) comprises an area exposed between the flanges (19) in contact with the environment, and - one of the provided corrosion protection elements (1, 3) is in each case attached to the area of at least one of the screws (21) that is in contact with the environment.

12. The field device as claimed in claims 6 to 10 for recording, measuring and / or monitoring a measured variable of a filling material in a container, characterized in that - the field device comprises a part (A) to be arranged inside the container and a part (B) to be arranged outside the container, - at least one of the two parts (A, B) comprises a component, in particular a housing (35, 37), to which a corrosion protection element (3) is attached, wherein the corrosion protection element (3) is in particular a corrosion protection element (3) attached or clamped onto a tapered housing section (45, 47) of the respective housing (35, 37).