Mobile device for carrying out an electrochemical analysis, and method therefor

Abstract

The invention relates to a device (1) for the mobile electrochemical analysis of a metal part (2), in particular for carrying out a DL-EPR method. In order to enable a particularly simple and simultaneously precise electrochemical analysis, according to the invention the device is provided with: a measuring electrode (3) which can be connected to the metal part (2) to be examined; a counter electrode (4); a reference electrode (5); and a voltage source by means of which an electric voltage can be generated between the counter electrode (4) and the measuring electrode (3) and / or between the reference electrode (5) and the measuring electrode (3), wherein the device (1) is designed to detect a current via the measuring electrode (3), the reference electrode (5), and / or the counter electrode (4), wherein the counter electrode (4) and the reference electrode (5) are arranged in a working chamber (6) which can be filled with a fluid, in particular a test liquid, and has an opening (7), wherein a seal (9) surrounding the opening (7) is provided on the outside of the opening (7), such that the device (1) can be placed onto the metal part (2) in such a way that a region of the metal part (2) to be analysed can be fluidically connected to the working chamber (6) via the opening (7), and this region is fluidically separated from the surroundings by the seal (9). The invention also relates to a method for the electrochemical analysis of a metal part (2), in particular for carrying out a DL-EPR method.

Description

[0001] Mobile device for carrying out an electrochemical analysis and method therefor

[0002] The invention relates to a device for the mobile electrochemical analysis of a metal part, in particular for carrying out a DL-EPR method.

[0003] The invention further relates to a method for the electrochemical analysis of a metal part.

[0004] Methods and devices for carrying out electrochemical analysis are well known from the state of the art, in particular from the standard DIN EN ISO 12732.

[0005] The document DE 19749 111 A1 discloses a device for electrochemical analysis using the so-called double-loop electrochemical potentiokinetic reactivation test (DL-EPR method for short).

[0006] State-of-the-art devices and methods have the particular disadvantage that carrying out a corresponding electrochemical analysis involves great effort.

[0007] This is where the invention comes in. The object of the invention is to provide a device with which electrochemical analysis can be carried out with particularly low effort.

[0008] Furthermore, such a procedure should be specified.

[0009] The first object is achieved according to the invention by a device for the mobile electrochemical analysis of a metal part, in particular for carrying out a DL-EPR method, which device has a measuring electrode which can be connected to a metal part to be examined, a counter electrode and a reference electrode as well as a voltage source by which an electrical voltage can be generated between the counter electrode and the measuring electrode and / or between the reference electrode and the measuring electrode, wherein the device is designed to detect a current via the reference electrode and / or via the counter electrode, wherein the counter electrode and the reference electrode are arranged in a working space which can be filled with a fluid, in particular with a liquid, and has an opening, wherein a seal enclosing the opening is provided on the outside of the opening, so that the device can be placed on the metal part in such a way thatthat an area of ​​the metal part to be analyzed can be fluidically connected to the working space via the opening and that this area is fluidically separated from the environment by the seal.

[0010] The counter electrode and the reference electrode can, in principle, be arranged anywhere in the working space. It is preferred that the counter electrode be placed next to or above the reference electrode to avoid shadowing effects. A helical arrangement of the counter electrode around the reference electrode is also possible.

[0011] Within the scope of the invention, it was recognized that a significant portion of the effort required to conduct an electrochemical analysis using prior art methods is due to the fact that prior art methods can only be performed in laboratories, so that disassembly of the component to be analyzed and its transport to a laboratory is always necessary. This effort is avoided with a device according to the invention, as it is mobile and thus the device, which can be of compact design, can be brought to a metal part to be analyzed in order to conduct the electrochemical analysis on the metal part, which in principle can also be installed in a system.

[0012] For this purpose, the device according to the invention has, analogously to devices known from the prior art, for example analogously to devices known from the document DE 19749 111 A1, a counter electrode, a reference electrode and a measuring electrode in order, for example, to apply a voltage between the counter electrode and the component to be examined or the measuring electrode, to fluidically connect the metal part in the area to be examined to the working space, which is filled with a test liquid, for example a normal sulfuric acid, in order to be able to draw conclusions about the state of the metal, in particular about intergranular corrosion, on the basis of a current flow between the reference electrode and the measuring electrode.

[0013] It is understood that the terms measuring electrode, counter electrode, and reference electrode are not to be interpreted restrictively. For example, according to the ISO 12732 standard, the measuring electrode would be referred to as the working electrode, the counter electrode as the auxiliary electrode, and the reference electrode as the reference electrode. These terms can therefore be considered synonyms for the terms measuring electrode, counter electrode, and reference electrode used here.

[0014] Due to the possibility of connecting the measuring electrode, the counter electrode and the reference electrode differently to one another or of applying voltages between these electrodes as desired and of measuring currents via one or more of these electrodes, the device according to the invention can be used to carry out a wide variety of electrochemical analysis methods, in particular, but not only, for carrying out the DL-EPR method.

[0015] Optionally, a closure can be provided for reversible closure of the opening. Furthermore, the reference electrode can be directly equipped with a special seal that allows the opening to be sealed leak-proof.

[0016] The opening can, in principle, have any desired diameter. To ensure efficient implementation of the method while simultaneously achieving high-quality analysis results, it is preferred that the opening has a diameter of less than 20 mm, in particular between 2 mm and 10 mm.

[0017] It has proven useful that the counter electrode is positioned in the working space adjacent to the opening, in particular at a distance from the opening of less than 100 mm, in particular less than 50 mm, preferably less than 40 mm.

[0018] The reference electrode can, for example, comprise a silver wire in a housing, similar to that described in document DE 197 49 111 A1. This housing is ion-permeable but liquid-tight at its ends. Here, too, the interior of the reference electrode housing can be filled with a one-molar potassium chloride solution, although other liquids, such as a three-molar potassium chloride solution, can also be used. It has proven effective to position the reference electrode directly above the opening to the measuring electrode, preferably at a minimum distance of approximately twice the opening diameter.

[0019] With the device according to the invention, the method can then be easily carried out in a mobile manner by placing the device dry on an area of ​​a metal part to be analyzed with the seal surrounding the opening. The working chamber is then filled with a test fluid so that the test fluid can also penetrate into the area between the opening and the metal part to be analyzed. The seal prevents the test fluid from escaping and prevents air from entering. The electrochemical analysis can then be performed.

[0020] To perform the DL-EPR method, for example, the measuring electrode is connected to the metal part to be examined, for example with a clamp or the like, after which a voltage between the counter electrode and the measuring electrode is increased gradually or continuously using the voltage source. State-of-the-art feed rates or scan rates of, for example, 6 V / h can be used for this purpose. At the same time, a current flow across the counter electrode and a voltage between the reference electrode and the measuring electrode are measured. As is usual with the DL-EPR method, the voltage is first increased and then reduced, and polarization is reversed in order to record the current during both activation and reactivation. Based on the currents and voltages measured during reactivation and activation, or the temporal progression of these variables, a condition assessment can ultimately be made.

[0021] It has proven to be advantageous if the device has at least one connection for a liquid container, in particular in cartridge form, with which a test liquid can be transported, on which a liquid line, which in particular has a valve for reversibly closing the liquid line, is provided, via which the container, which is sealed several times, can be placed on the measuring cell, which contains the working space with the test liquid, and is thus connected to the working space in order to be able to fill the working space with test liquid and empty it again as needed.

[0022] It has proven advantageous if the device has at least one liquid container with which a test liquid can be transported, with which a liquid line is provided, which in particular has a valve for reversibly closing the liquid line, via which the container is connected to the working space in order to be able to fill the working space with test liquid as required.

[0023] The quality of many electrochemical analysis methods depends on the temperature during the analysis. For example, the DL-EPR method is preferably carried out at a temperature of approximately 30 degrees Celsius for the metal part to be analyzed and the test fluid. It can therefore be advantageous if the fluid container and / or the working chamber are equipped with a temperature sensor to enable continuous analysis of the temperature of the test fluid. Furthermore, a heating device and / or a cooling device can be provided to heat the fluid container and / or to heat or cool the working chamber in order to bring the test fluid to the appropriate temperature and, if necessary, to maintain it at this temperature during the method, for example, when using the device to analyze weld seams on pipelines in cold regions.

[0024] The device can also have one or more receptacles for cartridges containing the test fluid. These receptacles can be temperature-controlled and / or temperature-monitored, making it easy to ensure that the test fluid is present at the correct temperature. In particular, the cartridges for the test fluid can also be thermally insulated for this purpose.

[0025] Different electrochemical analyses and / or different metals may require different test fluids. It can therefore be advantageous if the device has receptacles for different cartridges connected to the working chamber, so that the working chamber can be filled with the correct fluid as required. For this purpose, lines are usually provided from the individual cartridges to the working chamber, which can be closed by controlled valves. Alternatively or additionally, pumps can also be provided, through which the respective test fluid can be pumped from the respective cartridge into the working chamber.

[0026] In order to avoid electrical shadowing effects, it has proven advantageous if the counter electrode is arranged helically around the reference electrode, especially if the test liquid has only a low conductivity.

[0027] It is advantageous to provide a device for transporting the test fluid from the fluid container to the working chamber, particularly a pump. This allows the test fluid to be applied both to the metal part to be analyzed and to fill the working chamber, so that the test fluid contacts the counter electrode, the reference electrode, and the metal part, even when the device is used, for example, for overhead analysis of a metal part, i.e., when the opening is located above the working chamber.

[0028] It has proven useful for the liquid container to have multiple layers, with at least one layer being an insulating layer for thermally insulating the interior of the liquid container from the surrounding environment. This allows pre-heated liquid containers to be inserted into the device to conduct an electrochemical analysis at the correct temperature. For this purpose, the liquid containers are preferably arranged detachably in the device, in particular as sealable cartridges.

[0029] Preferably, a temperature sensor is provided to determine the temperature in the workspace and / or the temperature of the metal part. By monitoring the temperature, high analysis quality can be ensured even during the analysis.

[0030] To achieve a desired temperature during the analysis, a heating device is preferably provided to control the temperature of the fluid in the working chamber and / or the metal part. The heating device can be, for example, a resistance heater, an inductive heater, or another heating device known from the prior art, for example, one or more electrothermal converters such as Peltier elements.

[0031] Depending on the application, cooling the area to be examined may also be appropriate to achieve the temperature optimal for the respective electrochemical analysis. A cooling device can therefore also be provided to regulate the temperature of the fluid in the working chamber and / or the metal part. Thus, the device can also be used, for example, to examine pipes in operating power plants.

[0032] A gas container can optionally be provided with which a gas, in particular a noble gas such as argon, can be transported, wherein a gas line, which in particular has a valve for the reversible closing of the gas line, is provided, through which the gas container is connected to the working chamber, preferably to a region near the opening, in particular to an overflow region adjacent to the opening, which is delimited by the seal in order to be able to remove air in the working chamber and / or in the region of the seal by blowing gas out of the container. It has been shown that ambient air which is present in the working chamber and in the region of the seal before the working chamber is filled with the test liquid can falsify an analysis result.This falsification can be easily avoided by purging the working chamber and the overflow area between the opening and the metal part, which is defined by the seal, with an inert gas before performing the analysis. This expels any air present from this area before the test fluid is added.

[0033] Alternatively, it would also be conceivable to remove the air from the working space and from the area between the seal, the metal part and the opening by sucking the air out using a compressor before or while the working space and the overflow area are filled with the test liquid.

[0034] The mobile device can, in principle, be powered in any manner known from the prior art, for example, via an electrical cable connected to the mobile device. To ensure particularly easy transport of the mobile device, an electrical energy storage device, in particular a rechargeable battery, is preferably provided. This storage device is arranged on the mobile device and can thus supply it with external power without additional cables.

[0035] It has proven useful to provide a data processing device with which the temporal progression of measured currents, voltages, and / or temperatures can be recorded. Preferably, the data processing device also allows for the evaluation of results or the performance of computational operations with measured currents, voltages, and / or temperatures in order to be able to perform an immediate evaluation.

[0036] It can also be provided that the data processing device has a wireless data transmission unit, in particular a modem, so that measured and / or calculated results can also be transmitted wirelessly, if necessary even during the analysis, for example via the Internet to a stationary data processing device or to a laptop near the device.

[0037] Optionally, a microscope and a digital camera connected to the microscope can be provided, allowing the digital camera to capture an enlarged image of the metal part. This allows for analysis. In addition to the analysis of measured currents, a visual analysis can be performed by photographing a section of the metal part magnified by the microscope. The photograph can also be processed via the data processing device and transmitted via a wireless data transmission device, allowing the results of the visual analysis to be captured during the analysis.

[0038] It is advantageous if a grinding device and / or a polishing device is provided with which an area of ​​the metal part to be analyzed can be mechanically pretreated before the electrochemical analysis is carried out.

[0039] An oxygen sensor can also be optionally installed in the work chamber. This allows the oxygen content of the test fluid to be measured during the analysis, allowing for a preliminary assessment of the quality of the analysis or, if necessary, for the test fluid to be replaced.

[0040] It is particularly advantageous if a control device is provided that allows an electrochemical analysis to be carried out automatically and autonomously. The device can then, for example, be designed such that it performs an electrochemical analysis of a metal part of interest at a predetermined position completely autonomously.

[0041] For this purpose, it is advantageous if the device has a drive, which in particular comprises wheels and / or propellers and / or guide rails, by which the device can be moved toward a metal part to be analyzed. For example, the device can thus be used for the autonomous examination of weld seams on pipelines. The device can thus be designed, for example, as a vehicle that can be moved along a pipeline, if necessary, or as an aerial drone.

[0042] In this context, it is particularly advantageous if the device is designed to be detachably coupled to a pipeline and moved along the pipeline by means of a drive. The device can then, for example, perform a corresponding analysis on each weld seam. For this purpose, the device can also be designed to detect weld seams automatically, for example, using a camera.

[0043] Preferably, the device is designed to be releasably attached to a metal part to be analyzed. The attachment can be force-fitting and / or form-fitting, for example, using suction cups on the device, magnets, clamps, tensioning straps, or the like.

[0044] It is advantageous if the device has an adapter, in particular a rail, which can be connected to a component to be analyzed, in particular in a force-fitting manner, preferably via tensioning belts, wherein the working space is movable relative to the adapter, in particular translationally and / or rotationally. This enables a simple and at the same time stable connection of the device to a metal part to be examined. For example, the adapter designed as a rail can be connected at two positions to a component to be examined, which may have a round or square cross-section. Such a connection can be achieved, for example, via tensioning belts, by means of which the rail is rigidly connected to the component.In this case, the device is preferably designed such that the working chamber can be moved along the rail and, if necessary, also perpendicular to a longitudinal axis of the rail, in particular along a guide ring arranged in a plane perpendicular to a longitudinal axis of the rail. This allows the working chamber or seal to be supported on the rail and positioned at different positions on the component and pressed against a surface of the component to perform an electrochemical analysis.

[0045] If the adapter is designed for connection to a pipeline, it is preferably provided that the working space can be moved by one or more drives, preferably pneumatically, parallel and optionally normal to a longitudinal axis of the pipeline in order to be able to press the opening against different positions of the pipeline so that different positions of the pipeline can be examined automatically if necessary.

[0046] It can also be provided that a grinding and / or polishing device and a passivation cell, with which, for example, diluted nitric acid can be applied, are connected to the work space and are movable relative to the adapter in order to be able to first mechanically pretreat an area of ​​the component to be examined by means of the grinding and / or polishing device and, after carrying out the analysis, to passivate it by means of the passivation cell.

[0047] A drive for moving the working chamber, which may be part of a measuring cell, relative to the adapter is preferably pneumatic. This makes it particularly easy to avoid electrical interference with the evaluation, which could occur, for example, with a drive driven by an electric motor.

[0048] It can also be provided that the working space is rotatably movable relative to the adapter. This is particularly advantageous when the component to be examined is a pipeline and the adapter is fixedly connected to the pipeline. By rotating the working space relative to the adapter, examinations of the pipeline at different positions along the circumference of the pipeline are then possible. In this case, it is particularly preferred if the working space is rotatably movable relative to the pipeline about the longitudinal axis as well as translationally movable parallel to the longitudinal axis of the pipeline and translationally movable in a plane normal to the longitudinal axis, in particular radially. In this way, the working space or the opening can be moved to any position on the pipeline.It is advantageous if a drive, in particular a pneumatic drive, is provided to press the opening against the component to be examined with a force which results in a surface pressure of 1 N / mm in the seal. 2 up to 10 N / mm 2 This ensures a good sealing effect even on non-flat components such as pipes and weld seams.

[0049] In order to be able to analyze the inside of a pipeline as well, it is preferably provided that at least one, preferably two adjustable spreading devices are connected to the adapter, in particular at the end, by means of which the adapter can be non-positively fixed in a pipe, wherein each spreading device preferably has three stamps arranged at angles to one another, in particular at angles of 120 degrees, which can be moved in a translational manner, preferably pneumatically. The stamps are preferably arranged in such a way that they can be moved in the radial direction when positioned in the pipeline, so that a movement of all stamps enables the adapter to be fixed in two positions in the pipeline, resulting in a stable connection between the adapter and the pipeline.

[0050] In order to enable easy insertion into a pipeline, rollers can also be provided which are connected to the adapter, for example three rollers distributed over a circumference of the device, for example in the area of ​​the stamps.

[0051] In this case too, the adapter can be formed by a rail, for example, or have a rail. The rail is then held in the pipeline by the spreading devices, and the working chamber, which can be arranged in a measuring cell, and optionally further devices such as a microscope, a passivation cell, a grinding device and the like are then mounted in the pipeline via the rail and are preferably movable relative to the rail or relative to the adapter, in particular in the longitudinal direction of the pipeline, in the circumferential direction and in the radial direction. In this way, a partially or fully automated examination of the inside of a pipeline can be carried out. This includes the mechanical pre-treatment, the actual electrochemical analysis by means of the working chamber, as well as the subsequent passivation and any optical examinations or

[0052] may include documentation.

[0053] In order to be able to examine different positions of the pipeline in the circumferential direction, it is preferably provided that the spreading devices are connected to the working space via a rotation device, which in particular has a drive on each spreading device, so that the working space can be rotated relative to the spreading devices when the working space is mounted in a pipeline via the spreading devices. In this way, for example, a polishing device, a measuring cell, and a passivation cell can be positioned in the pipeline so that they can rotate relative to the pipeline. The rotation device can, for example, have a rotation drive formed by an electric motor.

[0054] It is advantageous if the spreading device can be detachably connected to the adapter at different positions, in particular via elongated holes, in order to be able to adapt the device to pipes of different diameters.

[0055] In order to be able to easily achieve a particularly stable fixation of the device even in pipes with small diameters, it is preferably provided that at least one punch of the spreading device is movable by a mechanism, in particular a scissors mechanism, wherein the mechanism preferably converts a movement of an actuator in the longitudinal direction into a movement of the punch in the radial direction. The actuator, in particular a pneumatic drive, can then be aligned in the longitudinal direction of the pipe, so that good fixation is possible even in small pipes. As an alternative to a scissors mechanism, another mechanism can of course also be used which converts a movement of an actuator in one direction into a movement of the punch in another direction.

[0056] In order to be able to passivate an analyzed area in a simple manner after the analysis has been completed, a passivation cell is preferably provided which has several, preferably four, individually movable segments with which an electrochemically analyzed area of ​​the metal part can be cleaned and passivated. The segments can be designed for dry and, if necessary, wet cleaning, in particular with distilled water, of the analyzed area and for passivation, for example for applying a passivation liquid such as 10% nitric acid, and finally for removing any excess passivation liquid. The segments are individually movable and can thus be placed against the analyzed metal part in order to first clean the analyzed area of ​​the metal part and then pass through it.In a device that can be inserted into a pipe, the segments are typically individually radially movable so that they can be pressed individually against the inside of the pipe. Movement of the individual segments can be achieved, for example, by pneumatic drives.

[0057] Pipelines are usually manufactured as sections and then connected, for example as sections with a length of 6 m. In order to be able to examine these sections also on the inside over their entire length, it is preferably provided that an introduction device, in particular a flexible rod, is connected to at least one of the spreading devices in order to be able to introduce the working space together with the adapter into a pipeline, in particular to a depth of more than 2 m, preferably about 3.5 m.

[0058] It is advantageous if a grinding device and / or a polishing device is connected to the adapter in order to mechanically pretreat the inside of a pipeline. A drive motor for this purpose is arranged externally, in particular at least 30 cm from the grinding and / or polishing device, and mechanical energy is transmitted from the drive motor to the grinding and / or polishing device via a shaft, in particular a flexible shaft. This means that a conventionally electric drive for the grinding and / or polishing device is located far away from the work area or the measuring cell, thus easily avoiding electromagnetic interference with the measuring cell.To remove any chips from the area to be analyzed, a cleaning device, in particular a compressed air nozzle connected to a compressed air reservoir, can also be provided, with which chips formed, for example, during grinding or polishing can be removed. Furthermore, it is advantageous if the device is designed to automatically establish electrical contact between the measuring electrode and the metal part. For this purpose, for example, a clamping device can be provided that can clamp the measuring electrode to the metal part. Of course, another type of connection is also possible, for example, a magnetic connection.

[0059] The further object is achieved according to the invention by a method for the electrochemical analysis of a metal part, in particular for performing a DL-EPR method, which is carried out using a mobile device. The method according to the invention is preferably carried out using a device according to the invention.

[0060] The method can then be carried out, for example, by moving the device to an area of ​​a metal part to be analyzed, either manually or by means of a drive, after which the area of ​​interest is mechanically prepared, if necessary, in particular by grinding and cleaning. For this purpose, the device can be equipped with appropriate grinding and cleaning devices.

[0061] In the next step, the device, with the seal surrounding the opening, is placed dry onto the area of ​​the metal part to be analyzed, after which the working chamber is filled with test fluid. If necessary, argon or another noble gas can be filled into the working chamber and the area between the opening and the metal part before or during placement in order to displace any air present in this area. The test fluid is then filled into the working chamber. This test fluid then connects the counter electrode and the reference electrode and penetrates into the area between the opening, seal, and metal part, thus connecting the metal part to the counter electrode and reference electrode, after which the measuring electrode is connected to the metal part. It goes without saying that the above steps can also be carried out in a different order.

[0062] The device is preferably provided with a surface pressure of 1 N / mm2 up to 10 N / mm 2 pressed against the object or component under test. It has been shown that this reliably prevents air penetration and the leakage of the test fluid, ensuring high-quality test results.

[0063] In the next step, for example, a DL-EPR method is performed, in which the voltage between the counter electrode and the measuring electrode is continuously or gradually increased, a voltage is measured between the reference electrode and the measuring electrode, and a current is measured via the counter electrode. The current measured during reactivation and activation and / or the amount of charge across the counter electrodes can be used to determine the condition of the metal part.

[0064] Using an electronic unit, a voltage is typically applied to the terminals for the measuring electrode, which is connected to the metal part, and the counter electrode. The voltage between the measuring electrode and the reference electrode, as well as the current flowing through the counter electrode, is measured. The voltage between the measuring electrode and the counter electrode is varied during the measurement and, if necessary, reversed. It is advantageous to vary the voltage step by step, and after each step, the voltage between the measuring electrode and the reference electrode, as well as the current flowing through the counter electrode and, if applicable, the amount of charge, are measured, displayed, stored, and evaluated.

[0065] After the electrochemical analysis is complete, the area where the analysis was performed can be passivated, for example, with diluted nitric acid. An optional cap provided on the opening can then be closed.

[0066] The method according to the invention can in principle be used for the electrochemical analysis of any metal, in particular for the analysis of so-called super duplex steels.

[0067] The method can be used on installed workpieces as well as on workpieces in production, for example, immediately during or after a processing step or the creation of a weld seam, in order to detect potential defects as early as possible. Further features, advantages, and effects of the invention will become apparent from the exemplary embodiment presented below.

[0068] The drawings referred to show:

[0069] Fig. 1 shows a device according to the invention in a schematic representation;

[0070] Fig. 2 shows another device according to the invention in an isometric view;

[0071] Fig. 3 shows a further device according to the invention;

[0072] Figs. 4 and 5 show a further device according to the invention in different views; Figs. 6 to 12 show a further device according to the invention in different views.

[0073] Fig. 1 shows a schematic diagram of a device 1 according to the invention. As can be seen, the device 1 has a working chamber 6 in which a counter electrode 4 and a reference electrode 5 are arranged. The reference electrode 5 is approximately cylindrical and can comprise a silver wire in a housing that is ion-conductive but liquid-tight relative to the working chamber 6.

[0074] The counter electrode 4 is arranged helically around the reference electrode 5 and can, for example, have a platinum wire or consist of a platinum wire.

[0075] To perform the electrochemical analysis, the working chamber 6 is filled with a test fluid, for example, a fluid consisting of 15% sulfuric acid, 5% hydrochloric acid, potassium thiocyanate, and the remainder water, which fluid is filled into the working chamber 6 via a container designed as a cartridge 10. For this purpose, a pump (not shown in Fig. 1) can be provided in a fluid line 17 between the fluid container and the working chamber 6.

[0076] Certain electrochemical analysis methods require a specific temperature during the analysis. For example, a temperature of approximately 30 degrees Celsius at the measuring point is advantageous for carrying out the DL-EPR method. In order to be able to guarantee this temperature even when using the device 1 on site, for example on pipelines in Siberia, the cartridge 10 can be pre-heated, for example to 30 degrees Celsius, and inserted into the device 1 at this temperature, after which the analysis is carried out, preferably shortly after inserting the cartridge 10. This ensures that the analysis is carried out at the correct temperature. For temperature monitoring, temperature sensors 11 can be provided on the cartridge 10, in the working chamber 6 and / or in the overflow region 14, wherein the temperature sensors 11 can be designed in any way known from the prior art.Furthermore, a heating device and / or a cooling device can be provided for tempering the area of ​​the metal part 2 and / or the working space 6 to be examined.

[0077] The heating device can also be designed to bring the test fluid in the working chamber 6 and / or in the cartridge 10 to a temperature that depends on the outside temperature, thus ensuring that the test fluid is at the intended temperature during the measurement. For example, the cartridge 10 can be pre-heated to 60 °C in order to achieve a temperature of 30 °C during the measurement.

[0078] The working chamber 6 has an opening 7 at a lower end, which has, for example, a diameter of 1 mm to 10 mm, preferably 2 mm to 5 mm. Optionally, a closure can also be provided at this opening, by means of which the opening can be reversibly closed, so that the working chamber 6 can be sealed off from the environment in a liquid-tight manner. The opening 7 is surrounded on the outside by a seal 9, for example an O-ring or the like, in order to enable the device 1 to be applied tightly to a metal part 2. The seal 9 can also be particularly soft, so that the device 1 can also be applied to a curved body, for example a pipe.

[0079] Furthermore, a gas line 16 is optionally provided, which projects into an overflow area 14 which borders on the outside of the opening 7, in order to purge this overflow area 14 and the working chamber 6, which are usually filled with air before the device is placed on the metal part 2, with an inert gas, for example a noble gas, so that the air escapes. This purging with argon, for example, can last for a few seconds to a few minutes in order to remove air, in particular oxygen, as completely as possible from the working chamber 6 and the adjacent overflow area 14. For this purpose, a gas line 16 is provided with a gas container 13 which is connected via a valve and is usually under excess pressure so that air can be forced out of the overflow area 14 by means of the noble gas. Alternatively, the gas line 16 can also protrude into the working chamber 6.

[0080] Furthermore, a heating device (not shown) and a temperature sensor 11 are provided for the targeted heating of the area of ​​the metal part 2 which is to be analyzed.

[0081] Furthermore, an oxygen sensor 12 can be provided in the working chamber 6 to determine the oxygen concentration in the working chamber 6, which is relevant for the quality of the analysis result. It has been shown that the oxygen content is already within an acceptably low range after just a few minutes of purging the working chamber with a noble gas. Since the measuring cell is completely sealed after being placed on the sample surface, no further oxygen can penetrate, so an oxygen sensor is not absolutely necessary.

[0082] Outside the working space 6, a measuring electrode 3 is provided, which can be connected to the metal part 2 to be examined by a clamp or the like.

[0083] Measuring electrode 3, reference electrode 5, and counter electrode 4 are connected to an electronic unit 15, by means of which a voltage can be applied between measuring electrode 3, reference electrode 5, and / or counter electrode 4, which voltage can also be freely varied. Furthermore, the electronic unit 15 makes it possible to measure a current via measuring electrode 3, reference electrode 5, and / or counter electrode 4 and to record applied or measured time profiles of voltages and currents, making device 1 suitable for conducting a wide variety of mobile electrochemical analyses.

[0084] As shown, the temperature sensor 11 and the oxygen sensor 12 are also connected to the electronics unit 15, so that related data can also be recorded by the electronics unit 15. The electronics unit 15 is also designed to perform mathematical operations on data, in particular on the temporal profiles of currents and voltages, in order to be able to perform immediate evaluations.

[0085] The device 1 is preferably particularly suitable for carrying out a DL-EPR method, wherein a voltage is applied between the measuring electrode 3, which is electrically connected to the metal part 2, and the counter electrode 4, and a current from the counter electrode 4 to the measuring electrode 3, as well as a voltage between the reference electrode 5 and the measuring electrode 3, is measured. The applied voltage is increased continuously or stepwise, then reduced, and if necessary, the polarity is reversed. The electronics unit 15 thus also serves as a variable voltage source for the voltage between the measuring electrode 3 and the counter electrode 4, for detecting the current from the counter electrode 4 to the measuring electrode 3 or to the metal part 2, and for determining the voltage between the reference electrode 5 and the measuring electrode 3.

[0086] The device 1 can be compact and is particularly suitable for manual, mobile electrochemical analysis by transporting it to a metal part 2 to be examined, which is then subsequently analyzed. For this purpose, the device 1 can also be supplied with power externally via cables, and a data processing device for evaluating measurement results can be connected to the electronics unit 15 via a data connection, in particular via a wired data connection.

[0087] However, the device 1 can also be designed for autonomous and partially or fully automated electrochemical analysis and for this purpose have a drive (not shown) in order to independently drive or fly to a metal part 2 to be examined. For this purpose, the device 1 can also be designed for independent navigation and, for example, have a modem and a GPS module. Furthermore, a device for fixing the device 1 to the metal part 2 and for the mechanical preparation of the metal part 2 can be provided, in particular a grinding and polishing device, and an energy storage device can be provided in the device 1, so that no external power supply is required. Fig. 2 shows a further device 1 according to the invention, which is designed for attachment to a pipe 18 such as a pipeline and can move along the pipeline with wheels 19.A drive can also be provided to drive these wheels 19, so that the device 1 can move independently along the pipeline 18. For this purpose, the device has a frame connected to the wheels, which supports the other devices of the device, in particular the electronics unit, the working chamber, the measuring electrode, the counter electrode, and the reference electrode. With regard to the other features, this device 1 is constructed analogously to that shown in Fig. 1 and can, in particular, also have a grinding and polishing unit to mechanically prepare the metal part to be examined for analysis.

[0088] The device 1 according to the invention can also comprise a data processing device and a modem, an optical magnification device, such as a microscope, an endoscope, or a lens with a digital camera, and a grinding device to enable a complete electrochemical analysis with appropriate mechanical preparation. Finally, a container containing a liquid for passivation, such as diluted nitric acid, can also be provided after the analysis.

[0089] The test liquid can, for example, be provided in cartridges 10 which are kept or pre-tempered at a predefined temperature in order to be able to provide the temperature required for carrying out the electrochemical analysis, for example the DL-EPR method.

[0090] Fig. 3 shows a further device 1 according to the invention, which is connected to a pipeline 18 via an adapter 21. The adapter 21 is connected to the pipeline 18 via tensioning belts 20 and has rails 22, relative to which the working chamber 6 is movable in order to move the opening 7 parallel to the pipe axis and to press it against a position of the pipeline 18 to be examined, so that the working chamber 6 is movable in two directions relative to the pipeline 18, namely parallel to a longitudinal axis 23 of the pipeline 18 on the one hand and normal to the longitudinal axis 23 on the other hand. A drive 29 for this purpose is preferably pneumatic in order to minimize electromagnetic interference. Figs. 4 and 5 show a further device 1 according to the invention with an adapter 21 for attachment in a pipeline 18 in order to examine a pipeline inner wall. In Fig. 5, the device 1 is shown in the pipeline 18, while the

[0091] Pipe 18 is not shown in Fig. 4 for better recognition of the features of the device 1.

[0092] The adapter 21 also has a rail 22, which connects spreading devices 24 arranged at the end of the rail 22, by means of which the device 1 can be fixed in the pipeline 18. Movably connected to the adapter 21 or the rail 22 are a grinding and / or polishing device 27 for mechanically pretreating the position of the pipeline 18 to be examined, a measuring cell 31 with a working chamber 6 and an opening 7, which can be placed on the then pretreated position to carry out the analysis, and a passivation cell 28, wherein the area on which the analysis was carried out can be passivated with the passivation cell 28, for example with dilute nitric acid.The grinding and / or polishing device 27, the measuring cell 31 and the passivation cell 28 are rigidly connected to one another here, but can be moved translationally relative to the adapter 21 both in the longitudinal direction and in the radial direction with respect to the tube, wherein pneumatic drives can again preferably be provided for this purpose.

[0093] As can be seen, a rotation drive 32 is provided on each spreading device 24 in order to rotate the rail 22 together with the measuring cell 31 relative to the spreading device 24 or relative to the pipeline 18.

[0094] Furthermore, the grinding and / or polishing device 27, the measuring cell 31 and the passivation cell 28 are jointly rotatably movable relative to the adapter 21 or relative to the spreading device 24 in order to be able to mechanically prepare, examine and subsequently passivate various positions of the pipeline 18 along the circumference.

[0095] It is understood that to carry out the analysis, the device 1 is first arranged at the appropriate position in the pipeline 18, after which a mechanical pretreatment is carried out with the grinding and / or polishing device 27, after which the measuring cell 31 is moved longitudinally to the previously pretreated position and the electrochemical analysis is carried out, after which the passivation cell 28 is moved longitudinally to the appropriate position and the passivation is carried out, for example with dilute nitric acid.

[0096] As can be seen, a drive 29 for the grinding and / or polishing device 27 is not arranged in the grinding and / or polishing device 27, but rather at a distance from it, and mechanical drive energy is transmitted to the grinding and / or polishing device 27 via a flexible shaft 30. In this way, electromagnetic interference with the analysis by the drive 29 is avoided and, in addition, a particularly compact design of the device 1 is possible.

[0097] Results of the electrochemical analyses can be transmitted from the measuring cell 31, for example via a cable or wirelessly, to a data processing device outside the pipeline 18, for example a computer.

[0098] Fig. 5 shows a view of the device 1 viewed in the axial direction, wherein the spreading device 24 is very clearly visible. As can be seen, the spreading device 24 has three punches 25 arranged at an angle of 120 degrees to one another, which can be moved in translation, preferably by means of a pneumatic drive 29, in order to press the punches 25 radially outwards against the inner wall of the pipeline 18 and thus fix the spreading device 24 in the pipeline 18. The spreading device 24 is rigidly connected to the adapter 21, on which the grinding and / or polishing device 27, the measuring cell 31 and the passivation cell 28 are supported and relative to which they are movable, so that the stable arrangement of the spreading devices 24 allows a stable arrangement of the grinding and / or polishing device 27, the measuring cell 31 and the passivation cell 28. As can be seen in Fig. 4, the spreading devices 24 are at the end of the adapter 21 orthe rail 22 in order to enable particularly stable mounting of the grinding and / or polishing device 27, the measuring cell 31 and the passivation cell 28. In this way, a good fixation of the measuring cell for carrying out an analysis of the inner wall of the pipeline is possible, namely in pipelines which only have a diameter of, for example, 100 mm, although the device can of course also be used on larger pipelines which have, for example, a diameter of 150 mm or more. Connected to the spreading device 24 is an insertion device 26, which is clearly visible in Fig. 4, in order to be able to insert the device 1 into a pipeline 18 to a depth of, for example, 3.5 m.

[0099] It is understood that further devices 1 can also be connected to the adapter 21 of the device 1 shown in Figs. 4 and 5, for example a camera, a microscope or a data transmission device for wirelessly or wiredly transmitting data determined by the measuring cell 31 to a device located outside the pipeline 18.

[0100] Fig. 6 to 12 show a further device 1 according to the invention for installation in a pipeline 18. This device 1 corresponds in several features to the device 1 shown in Figs. 4 and 5, which is why, to avoid repetition, the features which distinguish this device 1 from that of Figs. 4 and 5 will be discussed here.

[0101] First, as can be seen, several rollers 39 are attached to the device 1 to allow the device 1 to be easily inserted into a pipeline 18. Here, the rollers 39 are attached to the spreading device 24.

[0102] Furthermore, the device 1 can be fixed in the pipeline 18 by means of stamps 25, which here are formed by rubber elements and can in turn be pressed against the inner wall of the pipe by means of spreading devices 24.

[0103] The spreading device 24 itself also differs from the spreading device 24 in Figs. 4 and 5 with regard to the mechanism used. For example, the spreading devices 24 of the exemplary embodiment in Figs. 6 to 12 have scissor mechanisms 33, whereby an extension of a piston 25 in the radial direction can be effected, in particular by a movement of an actuator in the longitudinal direction, so that a possibly limited space in the radial direction can be compensated for by an available space in the longitudinal direction and the device 1 can thus also be used for installation in pipelines 18 with a very small diameter. As can be seen in particular in Fig. 9, a spreading drive 40 of the spreading device 24, which can be formed, for example, by a pneumatic drive, acts on several scissor mechanisms 33, so that one drive 29 is not required for each piston 25, but one drive 29 for each spreading device 24 can be sufficient.

[0104] For attachment to pipes of different diameters, the spreader device 24 can be fixed at different positions relative to the central axis of the device 1. For this purpose, the scissor mechanisms 33 can be attached to elongated holes 38 in different positions, as is clearly visible in Fig. 9.

[0105] Here, too, a drive 29 for the grinding and / or polishing device 27 is not arranged in the grinding and / or polishing device 27, but rather at a distance from it, and mechanical drive energy is transmitted to the grinding and / or polishing device 27 via a flexible shaft 30, as is clearly visible in particular in Figs. 10 and 11. A compressed air nozzle can also be provided on the grinding and / or polishing device 27 in order to clean an area to be analyzed before this area is analyzed with the measuring cell 31.

[0106] Fig. 11 also shows supply lines 41, through which the device 1 is supplied with energy, in particular electrical energy and compressed air. Furthermore, data lines can of course also be provided in this area to transmit control data from outside the pipe to the device 1 and data from the measuring cell 31 to a computer located outside the pipe.

[0107] As can be seen in Fig. 11, three spreading devices 24, which have scissor mechanisms 33, are provided at opposite ends of the device 1 to enable stable positioning in the pipeline 18. To fix the device 1 in the pipeline 18, punches 25 are also arranged on the spreading devices 24, which can be pressed against an inner wall of the pipe by the spreading devices 24 to achieve fixation by frictional engagement.

[0108] Another difference between the device 1 of Fig. 6 to 12 and the

[0109] Device 1 of Figs. 4 and 5 consists in that the passivation cell 28 here has four segments which can be moved radially outwards or inwards relative to the rails 22 independently of one another.

[0110] A first segment 34 is designed to remove residues of the test fluid at the position being examined. This can be done mechanically, for example, using a cloth or sponge that is arranged radially outward on the segment and pressed against the position being examined.

[0111] A second segment 35 is designed to clean the examined area with a cleaning liquid, for example with distilled water.

[0112] A third segment 36 is designed to apply a passivation liquid, for example 10% nitric acid, to the area under investigation.

[0113] A fourth segment 37 is designed to remove residues of the passivation liquid.

[0114] The four segments are thus preferably positioned sequentially in the order of first segment 34, second segment 35, third segment 36, fourth segment 37 in the area of ​​the examined position of the component and then moved radially outwards to the examined area or pressed to the examined position, for example by a pneumatic drive, in order to first clean the area and then passivate it.

[0115] It is understood that this design of the passivation cell 28 with a plurality of individually movable segments is not limited to a passivation cell 28 of a device 1 which can be introduced into a pipe, but of course a passivation cell 28 which can be attached to the outside of a pipe or another metal part 2 can also have corresponding segments.

[0116] Fig. 12 shows a view of the device 1 in the axial direction, wherein the arrangement of the rollers 39 and the stamps 25 is clearly visible. As shown, the stamps 25 and wheels 19 are arranged on the scissor mechanisms 33 of the spreading devices 24 in such a way that they approximately touch an inner pipe wall, shown schematically here by a dash-dotted line, so that the device 1 can be inserted into the pipe via the rollers 39 and moved within the pipe. By moving the stamps 25 radially outward, the device 1 is force-locked in the pipe if necessary, so that an area to be examined can be prepared, analyzed, and finally cleaned.

[0117] With a device 1 according to the invention, an electrochemical analysis method is possible in a simple manner not only in the laboratory but also in a mobile manner, so that in particular there is no need to remove components to be analyzed and an analysis of weld seams is possible immediately after the weld seams have been produced, still during production.

Claims

Patent claims 1. A device (1) for the mobile electrochemical analysis of a metal part (2), in particular for carrying out a DL-EPR method, comprising a measuring electrode (3) which can be connected to the metal part (2) to be examined, a counter electrode (4) and a reference electrode (5), as well as a voltage source by which an electrical voltage can be generated between the counter electrode (4) and the measuring electrode (3) and / or between the reference electrode (5) and the measuring electrode (3), wherein the device (1) is designed to detect a current via the measuring electrode (3), the reference electrode (5) and / or via the counter electrode (4), wherein the counter electrode (4) and the reference electrode (5) are arranged in a working chamber (6) which can be filled with a fluid, in particular a test liquid, and has an opening (7), wherein a seal (9) enclosing the opening (7) is provided on the outside of the opening (7).so that the device (1) can be placed on the metal part (2) in such a way that a region of the metal part (2) to be analyzed can be fluidically connected to the working space (6) via the opening (7) and this region is fluidically separated from the environment by the seal (9).

2. Device (1) according to claim 1, characterized in that the device (1) has at least one liquid container with which a test liquid can be transported, wherein a liquid line (17), which in particular has a valve for reversibly closing the liquid line (17), is provided, via which the container is connected to the working space (6) in order to be able to fill the working space (6) with test liquid as required.

3. Device (1) according to claim 1 or 2, characterized in that the counter electrode (4) is arranged helically around the reference electrode (5).

4. Device (1) according to claim 3, characterized in that a device for transporting the test liquid from the liquid container to the working space (6) is provided, in particular a pump.

5. Device (1) according to claim 3 or 4, characterized in that the liquid container has several layers, wherein at least one layer is an insulating layer for thermally insulating an interior of the liquid container from an environment.

6. Device (1) according to one of claims 1 to 5, characterized in that a temperature sensor (11) is provided to determine a temperature in the working space (6) and / or a temperature of the metal part (2).

7. Device (1) according to one of claims 1 to 6, characterized in that a heating device is provided in order to temper the fluid located in the working space (6) and / or the metal part (2).

8. Device (1) according to one of claims 1 to 7, characterized in that a gas container (13) is provided with which a gas, in particular a noble gas such as argon, can be transported, wherein a gas line (16), which in particular has a valve for reversibly closing the gas line (16), is provided, through which the gas container (13) is connected to the working space, preferably a region near the opening (7), in particular to an overflow region (14) adjacent to the opening (7), which is delimited by the seal (9) in order to be able to remove air in the working space and / or in the region of the seal by blowing gas out of the container.

9. Device (1) according to one of claims 1 to 8, characterized in that a data processing device is provided with which time profiles of measured currents, voltages and / or temperatures can be recorded.

10. Device (1) according to one of claims 1 to 9, characterized in that a microscope and a digital camera connected to the microscope are provided, so that an enlarged representation of the metal part (2) can be captured with the digital camera.

11. Device (1) according to one of claims 1 to 10, characterized in that a grinding device and / or a polishing device is provided with which a region of the metal part (2) to be analyzed can be mechanically pretreated before carrying out the electrochemical analysis.

12. Device (1) according to one of claims 1 to 11, characterized in that a control device is provided by which an electrochemical analysis can be carried out automatically and autonomously.

13. Device (1) according to one of claims 1 to 12, characterized in that the device (1) has a drive, which in particular comprises wheels (19) and / or propellers, by means of which the device (1) can be moved towards a metal part (2) to be analyzed.

14. Device (1) according to one of claims 1 to 13, characterized in that the device (1) is designed to be detachably coupled to a pipeline (18) and to be moved along the pipeline (18) by means of a drive.

15. Device (1) according to one of claims 1 to 14, characterized in that the device (1) has an adapter, in particular a rail, which can be connected to a component to be analyzed, in particular in a force-fitting manner, preferably via tensioning belts, wherein the working space is movable relative to the adapter, in particular translationally and / or rotationally.

16. Device (1) according to claim 15, characterized in that at least one, preferably two adjustable spreading devices (24) are connected to the adapter (21), in particular at the end, by means of which the adapter (21) can be non-positively fixed in a tube (18), wherein preferably each spreading device (24) has three stamps (25) arranged at angles, in particular at angles of 120 degrees, to one another, which stamps can be moved in a translational manner, preferably pneumatically.

17. Device (1) according to claim 16, characterized in that the spreading devices (24) are connected to the working space (6) via a rotation device (32), which in particular has a drive on each spreading device, so that the working space (6) is rotatable relative to the spreading devices when the working space (6) is mounted in a pipeline (18) via the spreading devices (24).

18. Device (1) according to claim 16 or 17, characterized in that an introduction device (26), in particular a flexible rod, is connected to at least one of the spreading devices (24) in order to be able to introduce the working space (6) together with the adapter (21) into a pipeline (18), in particular to a depth of more than 2 m, preferably about 3.5 m.

19. Device (1) according to one of claims 16 to 18, characterized in that the spreading device (24) can be detachably connected to the adapter (21) at different positions, in particular via elongated holes (38), in order to be able to adapt the device (1) to pipes (18) of different diameters.

20. Device (1) according to one of claims 16 to 19, characterized in that at least one punch (25) of the spreading device (24) is movable by a mechanism, in particular a scissor mechanism (33), wherein the mechanism preferably converts a movement of an actuator in the longitudinal direction into a movement of the punch (25) in the radial direction.

21. Device (1) according to one of claims 1 to 20, characterized in that a passivation cell (28) is provided which has several, preferably four, individually movable segments (34, 35, 36, 37), with which segments (34, 35, 36, 37) an electrochemically analyzed area of ​​the metal part (2) can be cleaned on the one hand and passivated on the other hand.

22. Device (1) according to one of claims 15 to 21, characterized in that a grinding device and / or a polishing device (27) is connected to the adapter (21) in order to be able to mechanically pretreat an inside of a pipeline (18), wherein a drive motor (29) is arranged externally for this purpose, in particular at least 30 cm away from the grinding and / or polishing device (27), and mechanical energy is transmitted from the drive motor (29) to the grinding and / or polishing device (27) via a shaft (30), in particular a flexible shaft.

23. Method for the electrochemical analysis of a metal part (2), in particular for carrying out a DL-EPR method, characterized in that the method is carried out with a mobile device (1), in particular with a device (1) according to one of claims 1 to 22.

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