Measuring device and method for determining wear

Abstract

The present invention relates to a measuring device (1) comprising: - a measuring conduit (6) for conducting a flowable medium, wherein the measuring conduit (6) has an inner surface (20) wherein the inner surface (20) is designed to be at least partially electrically insulated; - at least one monitoring electrode (7) wherein the at least one monitoring electrode (7) is arranged on an electrically insulated portion of the inner surface (20) for contact with the medium; - a measuring device (2) for determining process characteristics of the medium; - a wear detection device (9) designed to determine at least one variable on the at least one monitoring electrode (7), the variable corresponding to wear of the monitoring electrode (7); and a method for determining wear.

Description

Technical Field

[0001] This invention relates to a measuring device, process plant, and method for determining wear. Background Technology

[0002] Measuring devices used to monitor the process characteristics of media are known from process automation. Typical process characteristics include, for example, the pressure and temperature of the media, flow rate and velocity, mass flow rate, and pH value. A frequently used example of a measuring device is a magnetic induction flow meter. Depending on the application, the media in the measuring pipeline may have abrasive properties. To ensure potentially long operating times for the measuring device, special housings, measuring pipe bodies, or linings are provided for the measuring pipeline. When using a lining, replacement can be provided by the user as wear increases. It may be advantageous to determine when the lining needs to be replaced without interrupting the process.

[0003] Magnetic induction flow meters are used to determine the velocity and volumetric flow rate of a medium flowing in a pipeline. A magnetic induction flow meter has a magnet system that generates a magnetic field perpendicular to the flow direction of the medium. A single coil is typically used for this purpose; permanent magnets are less common. To achieve a predominantly uniform magnetic field, pole shoes are additionally formed and attached to the measuring pipe such that the magnetic lines of force extend substantially perpendicular to the transverse axis of the measuring pipe or parallel to the longitudinal axis of the measuring pipe across the entire cross-section of the pipe. Measuring electrodes attached to the side surface of the measuring pipe tap the electrical voltage or potential difference in the medium, which is perpendicular to the flow direction and the magnetic field applied, and appears when the conductive medium flows in the flow direction when the magnetic field is applied. According to Faraday's law of induction, the tapped measuring voltage depends on the velocity of the flowing medium. u And by means of the known pipe cross-section, the volumetric flow rate is... V Voltage can be measured by induction. U Sure.

[0004] Magnetic induction flow meters are commonly used in fluid processes and automation engineering, and their conductivity is approximately 5 µS / cm. Corresponding flow meters are marketed by the applicant in various embodiments for a wide range of applications, for example, under the name PROMAG.

[0005] Due to the high mechanical stability required for the measuring pipe of a magnetic induction flowmeter, the pipe is typically composed of a metal carrier tube with a predetermined strength and width, lined internally with an electrically insulating material of a predetermined thickness, known as a lining. For example, DE 10 2005 044 972 A1 and DE 10 2004 062 680 A1 describe magnetic induction measuring sensors, including a measuring sensor capable of being inserted into a pipeline and comprising a first end on an inlet side and a second end on an outlet side, having a non-ferromagnetic carrier tube as an outer sheath for the measuring pipe, and a tubular lining housed within the inner cavity of the carrier tube and composed of an electrically insulating material for conducting the flow process medium electrically insulated from the carrier tube.

[0006] Liners, typically made of thermoplastic, thermosetting, and / or elastic plastics, are particularly used for chemical insulation between the support tube and the process medium. In magnetic induction measurement sensors where the support tube has high conductivity, for example, when a metal support tube is used, the liner also serves for electrical insulation between the support tube and the process medium, preventing short circuits caused by voltages induced in the process medium via the support tube. Therefore, the corresponding design of the support tube allows the strength of the measuring pipe to be adapted to the mechanical stresses present under the corresponding operating conditions, while the liner allows the measuring pipe to be adapted to the electrical, chemical, and / or biological requirements of the corresponding operating conditions.

[0007] So-called supports embedded in the liner are often used to secure the liner. For example, in patent specification EP 0 766 069B1, a perforated pipe welded to a carrier pipe serves as a support. The support is connected to the carrier pipe and is embedded in the liner by applying a material used to manufacture the liner inside the carrier pipe. Furthermore, a measuring pipe with a metal shell is known from patent specification US 4 513 624 A for mechanical stabilization and electrical shielding. For this purpose, the metal shell surrounds the conduit leading to the medium.

[0008] Furthermore, magnetic induction flowmeters are known to have a measuring pipe body formed of electrically insulating materials—such as plastics, ceramics, and / or glass. With such a measuring pipe, an insulating coating is eliminated.

[0009] It has been shown that despite the use of durable materials, the electrically insulating lining and the measuring pipe body formed by the electrically insulating material are susceptible to corrosion. In particular, process media carrying solid particles such as sand, gravel, and / or stones cause wear to the lining of the pipeline or measuring pipe body. Wear or deformation of the lining or electrically insulating measuring pipe body alters the flow profile of the measuring sensor. As a result, the measuring equipment transmits incorrect measurements of volumetric or mass flow rates. Furthermore, when the measuring pipe has an inner lining, the chemical or electrical insulation between the process medium and the carrier pipe is lost.

[0010] WO 2010 / 066518A1 discloses a measuring device for determining the volumetric flow rate and / or mass flow rate of a process medium flowing through a measuring pipe. The measuring pipe includes a carrier tube with a liner comprising a first layer and a second layer, and a monitoring electrode embedded between the first and second layers and configured to detect damage to the second / first layer. However, a disadvantage of this approach is the limited monitoring of the impact on the measurement of the volumetric flow rate and / or mass flow rate. Summary of the Invention

[0011] The problem addressed by this invention is to provide an alternative measuring device and method for determining wear, which solves the problem.

[0012] This problem is solved by the measuring device and the method according to the invention.

[0013] The measuring device according to the present invention includes:

[0014] - Measuring pipes used to guide flowable media.

[0015] The measuring pipe has an inner surface.

[0016] The inner surface is designed to be at least partially electrically insulated from the ground.

[0017] -At least one monitoring electrode,

[0018] At least one of the monitoring electrodes is arranged in dielectric contact on the electrically insulating portion of the inner surface;

[0019] - Wear detection equipment, which is designed to determine at least one variable on the at least one monitoring electrode, the variable corresponding to the wear of the monitoring electrode.

[0020] Known monitoring electrodes are metal foils embedded in linings or lead electrodes, on which the measurement circuitry of a wear detection device measures the resistance relative to a reference electrode in contact with the abrasive medium. According to the present invention, the monitoring electrode is in contact with the medium and thus directly exposed to the abrasive medium.

[0021] Wear detection equipment is a device designed to determine or measure the value of a variable (such as resistance, current, voltage, or related variables) at a monitoring electrode. This can be done with or without contact.

[0022] One embodiment provides that at least one monitoring electrode is designed as a selectively applied layer system that is at least partially conductive.

[0023] The layer system includes at least one conductive polymer layer and / or at least one doped semiconductor layer.

[0024] The layer system is preferably designed as a thin film and can have a layer thickness of a few nanometers to a few millimeters. The advantage of such a thin-layer system is that its variables, particularly resistance, as determined by wear detection equipment, depend directly on the change in layer thickness and therefore indirectly on the wear of the dielectric.

[0025] One embodiment provides that the layer system includes at least two conductive layers, each of which is made of a different material.

[0026] The preferred layer materials are stainless steel, CrNi alloy, ZnAl alloy, platinum, or titanium. For various applications, stainless steel grades 1.4435 and 1.4462 are used. The advantage of using at least two layers with different materials is that the wear rates of different materials can be derived based on determined variables. Therefore, the wear detection device is designed to determine a first wear rate for the first layer and a second wear rate for the second layer. In this case, the second wear rate is determined only when the first layer is removed and the determined variable value deviates from the target value range.

[0027] One embodiment provides that at least two layers each have resistance.

[0028] At least two of the layers are arranged such that the corresponding resistance is reduced in the radial direction, particularly in the direction of the center point of the measuring pipe.

[0029] The advantage of this is that the wear rate can be determined based on the change in resistance over time. If the layer system is intact, the current dominates in the layers with lower resistance. The removal of this layer is reflected in the value of the variable to be determined. The wear rate refers to a material-specific variable that provides information about removal over time—expressed by length, surface area, or volume. Based on the wear rate, the time required to replace measuring device components that contact the medium, such as linings or measuring electrodes, can be determined. Different resistances can be set by selecting materials with different specific resistivities or by using layers with different thicknesses.

[0030] One embodiment provides that at least two layers each have a layer thickness.

[0031] At least two of the layers are arranged such that the thickness of the respective layers increases in the radial direction, particularly in the direction of the center point of the measuring pipe.

[0032] Therefore, it is also possible to realize layer systems with layers of soft and therefore quickly removable layer materials—such as polymers that have higher electrical conductivity than thinner metal layers.

[0033] One embodiment provides that at least two layers each have a hardness.

[0034] At least two of the layers are arranged such that the corresponding hardness decreases in the radial direction, particularly in the direction of the center point of the measuring pipe.

[0035] The advantage of this is that a specific wear rate for a particular hardness can be determined, from which the maintenance cycle of other measuring device components made of materials with similar hardness can be inferred. The term hardness represents mechanical resistance, the resistance to the mechanical penetration of a material by another object—that is, a substance that causes wear in a flowing medium. Different types of hardness differ depending on the type of influence. Therefore, hardness is not only resistance to harder objects, but also resistance to softer and equally hard objects. Hardness is also a measure of a material's wear resistance.

[0036] One embodiment provides that the layer system has at least one electrically insulating layer that separates two conductive layers of at least two layers from each other.

[0037] Therefore, the effects of uneven wear can be prevented. If the electrical contact of one of the contact devices with the first layer is broken, only the resistance of the second layer is measured. This is essentially constant until the insulation layer is removed. Only when the second layer is removed and the insulation layer is thus at least partially removed does the resistance of the layer system subsequently change. This can be used to separate the different wear rates of the individual layers.

[0038] One embodiment provides that the layer of the layer system in contact with the inner surface is designed to be at least partially annular and / or have resistance. R 1, of which Especially And preferably .

[0039] This has the advantage that the monitoring electrodes are also suitable for grounding the medium to be conducted, which is particularly advantageous for magnetic induction flowmeters, where the lack of grounding leads to displacement of the measurement point.

[0040] One embodiment provides that the wear detection device is designed to measure at least one variable during a first time interval.

[0041] The wear detection equipment is designed to connect the layer system to ground potential for at least the second time interval.

[0042] One embodiment provides a wear detection device having contact means for electrical contact monitoring electrodes, the contact means specifically including a first contact means and a second contact means.

[0043] The wear detection device is designed to measure the impedance, in particular the resistance, on the at least one monitoring electrode, and to determine the at least one variable based at least on the impedance, and in particular on the time-varying changes in the resistance.

[0044] One embodiment provides that the contacting device has a first contacting device and a second contacting device.

[0045] The contact device includes a third contact device and a fourth contact device.

[0046] Specifically, the third and fourth contact devices are arranged between the first and second contact devices in the circumferential direction of the measuring pipe.

[0047] The wear detection equipment is designed to allow current to flow between the first and second contact devices.

[0048] The wear detection equipment is designed to measure the voltage between the third and fourth contact devices.

[0049] The wear detection equipment is designed to determine the thin-film resistance and, at least based on the thin-film resistance, particularly based on the time-varying changes in the thin-film resistance, determine at least one variable.

[0050] The advantage of this configuration is that it reduces the contact resistance between the contact device and the layer system, thus allowing for the detection of very small changes in the resistance of the layer system.

[0051] One embodiment provides that one of the at least one variables describes the material-related wear rate, and preferably another variable of the at least one variable describes the other material-related wear rate.

[0052] If only the wear rate related to the material or hardness is known, it is possible to determine the maximum operating time before replacing the measuring equipment or other components used in the process plant.

[0053] The process plant according to the present invention comprises:

[0054] - Pipelines,

[0055] -The measuring device according to the present invention,

[0056] The measuring equipment is connected to the pipeline.

[0057] The monitoring electrode has electrode material and / or coating material arranged on its inner surface.

[0058] One of the variables is specific to the electrode material and / or coating material.

[0059] - A component that also has electrode material and / or coating material, at least in the dielectric contact portion.

[0060] - Monitoring equipment,

[0061] The monitoring device is designed to output warnings for the plant component and / or determine the remaining operating time until maintenance measures for the plant component are implemented, based at least on variables and preferably on thresholds assigned to the plant component.

[0062] A method according to the present invention for determining the wear of the electrically insulating coating of a contact medium in a measuring device, particularly a measuring pipe of the measuring device according to the present invention, comprises the following steps:

[0063] -Measure the resistance of a thin film on a monitoring electrode, particularly in dielectric contact.

[0064] The monitoring electrodes are designed as a layer system;

[0065] -Based on the layer thickness of the layer system, the test variable is determined by measuring the thin-film resistance.

[0066] - Determine if wear exists based on test variables.

[0067] This invention applies to thin-film electrodes whose resistance depends on the layer thickness. Even small variations in layer thickness affect the measured resistance. The wear rate can be derived based on the time-varying resistance. Attached Figure Description

[0068] The present invention will be described in more detail with reference to the following drawings. The following are shown:

[0069] Figure 1 The longitudinal section of the measuring device according to the present invention;

[0070] Figure 2 Perspective view of a partial cross-sectional embodiment of the measuring device according to the present invention;

[0071] Figure 3 The longitudinal section of the measuring device according to an embodiment of the present invention;

[0072] Figure 4 A longitudinal section of the measuring device according to another embodiment of the present invention;

[0073] Figure 5 A longitudinal section of the measuring device according to another embodiment of the present invention;

[0074] Figure 6 A longitudinal section of the measuring device according to another embodiment of the present invention;

[0075] Figure 7 A longitudinal section of the measuring device according to another embodiment of the present invention;

[0076] Figure 8A longitudinal section of the measuring device according to another embodiment of the present invention;

[0077] Figure 9 Longitudinal cross-sectional view of the magnetic induction flowmeter; and

[0078] Figure 10 A view of a portion of the process plant. Detailed Implementation

[0079] Figure 1 A longitudinal section of a measuring device 1 according to the invention is shown. The measuring device 1 shown includes a measuring conduit 6 for conducting a flowable medium. The measuring conduit 6 consists of a metal carrier tube 3 and a liner 4 made of an electrically insulating material such as, for example, plastic. The liner 4 serves to insulate the carrier tube 3 from the medium. By applying the liner 4 to the inner surface of the carrier tube 3, the inner surface 20 of the carrier tube 3 is designed to be at least partially electrically insulated. Furthermore, the measuring device 1 has two monitoring electrodes 7, 26, which extend in a media-contact and circumferential manner on the electrically insulating portion of the medium on the inner surface 20 of the carrier tube 3 on the input and output sides. A measuring device 2 for determining the process characteristics of the medium to be conducted is part of the measuring device 1. A wear detection device 9 is designed to determine at least one variable on one of the two monitoring electrodes 7, 26, which corresponds to the wear of the monitoring electrode 7. Alternatively, the wear detection device 9 may be connected to both monitoring electrodes 7, 26, wherein one of the two values ​​of the determined variable can be used as a reference value. The wear detection device 9 is designed to determine the sheet resistance of the monitoring electrode 7, and to determine at least one variable based at least on the sheet resistance, particularly on the time-varying nature of the sheet resistance. The metal carrier tube 3 is electrically insulated from the wear detection device 9. The determined variable is a material-related wear rate representing the specific materials of the two monitoring electrodes 7, 26. Each of the two monitoring electrodes 7 is designed as a selectively applied conductive layer system 8, wherein the layer system 8 comprises at least one conductive polymer layer and / or at least one metal layer and / or at least one doped semiconductor layer. Furthermore, the layer system 8 has a width b and a thickness d, which, in addition to depending on the resistivity of the material, also determines the magnitude of the sheet resistance of the layer system 8. The wear detection device 9 may also be designed to measure at least one variable during a first time interval and connect it to ground potential during a second time interval. Thus, in addition to detecting the wear of the medium, the monitoring electrodes 7, 26 are also used to connect the flowable medium to a controlled potential.

[0080] Figure 2A perspective view of a partial cross-sectional embodiment of the measuring device 1 according to the invention is shown. The monitoring electrode 7 shown is designed in a ring shape and consists of a layer system 8 having a conductive layer 11. The ring can be designed to be closed or open. The contact device 13 has a first contact device 14, a second contact device 15, a third contact device 16, and a fourth contact device 17. In this case, the third contact device 16 and the fourth contact device 17 are arranged between the first contact device 14 and the second contact device 15 along the circumferential direction of the measuring conduit 6. The contact devices 14, 15, 16, and 17 are also distributed around the ring of the measuring conduit. Adjacent contact devices each have a substantially equal distance from each other, wherein this distance is greater than the thickness of the layer system 8 in each case. The wear detection device 9 is designed to allow current to flow between the first contact device 14 and the second contact device 15 and to measure the voltage between the third contact device 16 and the fourth contact device 17. The sheet resistance of the monitoring electrode 7 is obtained based on the magnitude of the measured voltage and current. At least one variable can be determined based at least on the sheet resistance, particularly on the time-varying nature of the sheet resistance.

[0081] Figure 3 A longitudinal section of an embodiment of the wear detection device 9 of the measuring apparatus according to the invention is shown. In this variation, the liner 4 can have a dimension of less than 2.5 mm, preferably less than 1.5 mm. For example, a liner as a relatively thin coated material can also be introduced into the carrier tube 3. Alternatively, the liner can also be a paint layer or designed as a plasma coating. Particularly advantageously, the liner thickness of the liner 4 can be from 50 µm to 1.5 mm, particularly from 200 µm to 1.3 mm. On the side facing the medium, the measuring tube 6 has a conductive layer 11. It can preferably be a metallic coating. The conductive layer 11 can preferably be applied as a conductive paint layer, as a conductive powder coating, and / or as a conductive plasma coating. The preferred layer thickness of the conductive layer is between 40 µm and 1 mm, preferably between 50 µm and 800 µm. These layer thicknesses ensure that the layer is sufficiently stable even under mechanical influence and can contact the contact device on the measuring tube side. The contact device is as follows: Figure 3As shown, a tapered lead electrode 27 is used. Of course, other electrode forms can also be implemented within the scope of the invention, among which such forms have proven particularly suitable for contact with metal coatings. In the case of plastic measuring tubes, electrode forms such as those in WO 2009 / 071615 A1 can also be used alternatively, which do not require additional anchoring equipment. In terms of manufacturing techniques, the lead electrode 27 can be passed through a hole in the measuring tube 6 or simply inserted into the carrier tube 3 until it contacts the conductive layer 11 from the outside—i.e., beyond the inner cavity of the measuring tube 6. It is also possible and easy to initially position the lead electrode 27 and then apply the conductive layer 11. Providing an electrically insulating liner 32 in the measuring tube 6 or the hole in the carrier tube 3 of the measuring tube 6 advantageously prevents contact between the metal carrier tube 3 and the lead electrode 27. The conductive layer 11 can be used in any type of measuring tube, but is particularly advantageous in measuring tubes with small inner diameters (DN100 or smaller) and measuring tubes with reduced and / or varied cross-sections in the region of the magnet system, as described, for example, in WO2016 / 102168A1. An anchoring system 28 for the lead electrode 27 is disposed on the side of the measuring pipe 6 facing away from the medium. It comprises two arms 29 and a platform 31. The two arms project obliquely from the outer wall of the measuring pipe 6 and converge toward each other, and the platform 31 is radially spaced from the outer wall of the measuring pipe and has a hole for the lead electrode 27 to pass through. This type of anchoring system 28 can also serve as a centering aid and as a stop when holes for electrodes are provided in the carrier tube 3, thereby guiding the drill bit and setting the holes at a defined height. Furthermore, the anchoring system 28 is used to prevent rotation of the lead electrode 27. An additional bonding layer may be disposed between the conductive layer 11 and the measuring pipe 6. However, advantageously, the conductive layer 11 may also be applied directly to the inside of the measuring pipe 6, particularly to the surface of the liner 4. The conductive layer 11 is position-selective. The material of the conductive layer 11 is preferably steel, but may also be another corrosion-resistant metal. Particularly preferred is the use of grade 1.4435 stainless steel, which is approved for drinking water applications. The arm 29 of the anchoring system 28 can be welded to the bearing tube 3.

[0082] Figure 4 A longitudinal section of another embodiment of the wear detection device according to the present invention is shown. Figure 4 A modified example embodiment of the carrier tube 3 made of plastic is shown. Therefore, it requires neither a liner nor an electrically insulating hole liner. The conductive layer 11, lead electrodes 27, and anchoring system 28 can be designed similarly to... Figure 3 .

[0083] Figure 5A longitudinal section of another embodiment of the wear detection device according to the invention is shown. The electrode variant has a first conductive layer 11 and a second conductive layer 12, the second conductive layer 12 preferably completely covering the first conductive layer 11 towards the medium. The materials of the first conductive layer 11 and the second conductive layer 12 differ in conductivity. The second conductive layer 12 can be composed of, for example, a material more corrosion-resistant than the first conductive layer 11. For example, steel, particularly stainless steel, such as grade 1.4435 for drinking water applications, can be used as the material of the second conductive layer 12, and copper, conductive plastics, or conductive semiconductors can be used as the material of the first conductive layer 11. Again, the removal of the second conductive layer 12 can be monitored, for example, by changing the resistance value, and an impending failure can be indicated. However, due to the presence of the first conductive layer 11, the measuring function of the electrode remains unchanged in this case. For example, a position-selective direct coating can be applied during a plasma coating process, and is known in particular from ecoCOAT Co., Ltd. With a layer applied in this way, an electrode surface can be created that protrudes only to a negligible degree into the pipe of the magnetic induction flowmeter, particularly the inner cavity of the measuring pipe. As a result, turbulence on the electrode surface is reduced or even completely prevented. Furthermore, in the case of a measuring conduit with a metal carrier tube, a smaller lining thickness can be selected because the electrode head was previously partially pressed into the lining material to avoid turbulence, which required a specific lining thickness, and this is no longer necessary. The lead electrode 27 and anchoring system 28 can be designed similarly to... Figure 3 .

[0084] Figure 6 A longitudinal cross-section of another embodiment of the wear detection device according to the present invention is shown. Two lead electrodes 27 and 33 are arranged one after the other in the conductive layer 11 and the measuring pipe in the flow direction A. If the front or inflow side region of the conductive layer 11 is removed, such removal can be detected by comparing the voltage and / or resistance of the respective electrodes 27 and 33 with respect to a reference electrode, and an impending fault can be signaled. In this case, repair can be performed in a relatively uncomplicated manner, as the inner side of the carrier tube 3 can be simply recoated in a position-selective manner.

[0085] Figure 7A longitudinal section of another embodiment of the wear detection device 9 according to the invention is shown. The layer system 8 consists of four separate layers, each with a different resistance, wherein the resistance is selected such that it decreases in the radial direction, particularly in the direction of measuring the center point of the pipe. Alternatively, each layer may have a different hardness, wherein the hardness decreases in the radial direction, particularly in the direction of measuring the center point of the pipe. Alternatively, each layer may have a different thickness, wherein the layer thickness is selected such that it increases in the radial direction, particularly in the direction of measuring the center point of the pipe. In addition to the electrically insulating layer, the layer system 8 also includes at least one electrically insulating layer 10 that separates the two conductive layers 11, 12 from each other.

[0086] Figure 8 A longitudinal section of another embodiment of the wear detection device 9 according to the present invention is shown. It is based on... Figure 2 An alternative embodiment has contact devices distributed around the circumference of the carrier tube. Contact devices 14, 15, 16, and 17 are uniformly distributed along the flow direction. The layer system is not necessarily designed as an annular band; instead, adjacent contact devices can each have substantially the same distance from each other, wherein this distance is greater than the thickness of the layer system 8 in all cases. The wear detection device 9 is designed to allow current to flow between the first contact device 14 and the second contact device 15, and to measure the voltage between the third contact device 16 and the fourth contact device 17. The sheet resistance of the layer system is obtained based on the magnitude of the measured voltage and current. At least one variable can be determined based at least on the sheet resistance, and particularly on the time-varying nature of the sheet resistance.

[0087] Figure 9 A longitudinal section of a magnetic induction flowmeter according to the invention is shown, which can be connected to a process line via a flange 5. The measuring device of the magnetic induction flowmeter has a magnetic field generating device 18 for generating a magnetic field through a measuring pipe 6, the device 18 being arranged on the outer surface of the measuring pipe 6. The magnetic field generating device 18 may include, for example, at least one saddle coil or at least one coil with pole shoes. Furthermore, the measuring device has an electrode assembly 19 for tapping the flow rate-related measurement variables induced in the medium. It typically consists of at least two radially arranged measuring electrodes. The electrode assembly 19 is arranged in the measuring section, and the measuring section, with a monitoring electrode 7 applied in the flow direction to the liner 4, forms a layer system 8. The layer system 8 is connected to a measuring circuit via a wear detection device 9, which is designed to implement the method according to the invention. The monitoring electrode 7, the wear detection device 9, and the measuring circuit together form a monitoring device 25.

[0088] Figure 10A view of a portion of a process plant 30 is shown, comprising pipeline 23, a measuring device 1 according to the invention, plant component 24, and monitoring device 25. The measuring device 1 is connected to pipeline 23 and has monitoring electrodes having an electrode material and / or coating material similar to that of plant component 24. The monitoring device 25 is designed to output warnings for plant component 24 and / or determine the remaining operating time until maintenance measures for plant component 24, based at least on at least one variable specific to the electrode material and / or coating material, and preferably on a threshold assigned to plant component 24.

[0089] List of reference numerals

[0090] Measuring equipment 1

[0091] Measuring device 2

[0092] Bearing pipe 3

[0093] Lining 4

[0094] Flange 5

[0095] Measuring pipe 6

[0096] Monitoring electrode 7

[0097] Layer system 8

[0098] Wear detection equipment 9

[0099] Electrical insulation layer 10

[0100] First conductive layer 11

[0101] Second conductive layer 12

[0102] Contact device 13

[0103] First contact device 14

[0104] Second contact device 15

[0105] Third contact device 16

[0106] Fourth contact device 17

[0107] Magnetic field generating device 18

[0108] Electrode device 19

[0109] Inner surface 20

[0110] outer surface 21

[0111] Process Plant 22

[0112] Pipeline 23

[0113] Factory Parts 24

[0114] 25 monitoring devices

[0115] Monitoring electrode 26

[0116] Pin electrode 27

[0117] Anchoring System 28

[0118] Arm 29

[0119] Process Plant 30

[0120] Platform 31

[0121] Lining 32

[0122] Pin electrode 33

Claims

1. A measuring device (1), comprising: - Measuring conduit (6), said measuring conduit (6) is used to conduct a flowable medium, The measuring pipe (6) has an inner surface (20). The inner surface (20) is designed to be at least partially electrically insulated from the ground. - At least one monitoring electrode (7). The at least one monitoring electrode (7) is arranged in dielectric contact on the electrically insulating portion of the inner surface (20). - Measuring device (2), the measuring device (2) is used to determine the process characteristics of the medium; - Wear detection device (9), said wear detection device (9) is designed to determine at least one variable on said at least one monitoring electrode (7), said variable corresponding to wear of said monitoring electrode (7), At least two layers each have resistance. The at least two layers are arranged such that the corresponding resistance decreases in the radial direction.

2. The measuring device (1) according to claim 1. wherein, The at least one monitoring electrode (7) is designed as a selectively applied conductive layer system (8). The layer system (8) includes at least one conductive polymer layer and / or at least one metal layer and / or at least one doped semiconductor layer.

3. The measuring device (1) according to claim 2. wherein The layer system (8) includes at least two conductive layers, each of which has a different material.

4. The measuring device (1) according to claim 3. wherein The at least two layers are arranged such that the corresponding resistance decreases in the direction of the center point of the measuring pipe.

5. The measuring device (1) according to claim 4. wherein Each of the at least two layers has a layer thickness. The at least two layers are arranged such that the thickness of the respective layers increases in the radial direction.

6. The measuring device (1) according to claim 5. wherein, The at least two layers are arranged such that the thickness of the respective layers increases in the direction of the center point of the measuring pipe.

7. The measuring device (1) according to claim 5. wherein Each of the at least two layers has a hardness. The at least two layers are arranged such that the corresponding hardness decreases in the radial direction.

8. The measuring device (1) according to claim 7. wherein, The at least two layers are arranged such that the corresponding hardness decreases in the direction of the center point of the measuring pipe.

9. The measuring device (1) according to any one of claims 1 to 8. wherein The layer system (8) has at least one electrically insulating layer (10) that separates two conductive layers of the at least two layers from each other.

10. The measuring device (1) according to any one of claims 1 to 8. wherein The layers of the layer system (8) which are in contact with the inner side surface (20) are designed to be at least partially annular and / or have an electrical resistance R 1. wherein .

11. The measuring device (1) according to claim 10. wherein 。 12. The measuring device (1) according to claim 10. wherein 。 13. The measuring device (1) according to any one of claims 1 to 8. wherein The wear detection device (9) is designed to measure the at least one variable during a first time interval. The wear detection device (9) is designed to connect the layer system (8) to ground potential for at least a second time interval.

14. The measuring device (1) according to any one of claims 1 to 8, comprising: wherein The wear detection device (9) has a contact device (13) for electrically contacting the monitoring electrode (7). The wear detection device (9) is designed to measure the impedance on the at least one monitoring electrode (7) and to determine the at least one variable based at least on the impedance.

15. The measuring device (1) according to claim 14. wherein The contact device includes a first contact device (14) and a second contact device (15).

16. The measuring device (1) according to claim 14. wherein The wear detection device (9) is designed to determine the at least one variable based on the time change of the impedance.

17. The measuring device (1) according to claim 14. wherein The contact device (13) has a first contact device (14) and a second contact device (15). The contact device (13) has a third contact device (16) and a fourth contact device (17). The third contact device (16) and the fourth contact device (17) are arranged in the circumferential direction of the measuring pipe (6) between the first contact device (14) and the second contact device (15). The wear detection device (9) is designed to allow current to flow between the first contact device (14) and the second contact device (15). The wear detection device (9) is designed to measure the voltage between the third contact device (16) and the fourth contact device (17). The wear detection device (9) is designed to determine the thin-film resistance and to determine the at least one variable based at least on the thin-film resistance.

18. The measuring device (1) according to claim 17. wherein, The wear detection device (9) is designed to determine the at least one variable based on the time-varying resistance of the thin film.

19. The measuring device (1) according to any one of claims 3 to 8. wherein, One of the at least one variables describes the material-related wear rate.

20. The measuring device (1) according to claim 19. wherein Another variable of the at least one variable describes the wear rate associated with another material.

21. The measuring device (1) according to any one of claims 1 to 8. wherein, The measuring device includes a magnetic field generating device (18) for generating a magnetic field that penetrates the measuring pipe (6). The magnetic field generating device (18) is arranged on the outer surface (21) of the measuring pipe (6). The measuring device includes an electrode device (19) for tapping the flow rate-related measurement variables induced in the medium. The electrode device (19) is arranged in the measuring section. The at least one monitoring electrode (7) is arranged on the input side and / or output side of the measuring pipe (6).

22. The measuring device (1) according to claim 21. wherein The at least one monitoring electrode (7) is arranged on the input side and / or output side of the measuring pipe (6) and at a certain distance from the measuring part.

23. A process plant (22), comprising: - Pipeline (23). - The measuring device (1) according to any one of claims 1 to 22. The measuring device (1) is connected to the pipeline (23). The monitoring electrode (7) has electrode material and / or coating material disposed on the inner surface. Wherein, one of the at least one variables is specific to the electrode material and / or the coating material, - Factory component (24), said factory component (24) also having the electrode material and / or the coating material at least in the dielectric contact portion, - Monitoring equipment (25) The monitoring device (25) is designed to output warnings for the plant component (24) and / or determine the remaining operating time until maintenance measures for the plant component (24) are performed, based at least on the variables.

24. The process plant (22) according to claim 23. wherein, The monitoring device (25) is designed to output warnings for the plant component (24) and / or determine the remaining operating time until maintenance measures for the plant component (24) are implemented, based at least on the variables and on the thresholds assigned to the plant component (24).

25. A method for determining wear of an electrically insulating coating in media contact with a measuring pipe (6) of a measuring device (1), said measuring device (1) being the measuring device (1) according to any one of claims 1 to 22, said method comprising the following steps: -Measure the resistance of the thin film on the monitoring electrode (7), wherein, The monitoring electrode (7) is designed as a layer system (8); -Based on the layer thickness of the layer system (8), the test variable is determined by the measured thin-film resistance. - Determine whether wear exists based on the test variables.

26. The method according to claim 25, wherein The resistance of the thin film on the monitoring electrode (7) in contact with the medium is measured.

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