Sensor, measuring device, method and use for analysing particles in fluids

Abstract

The invention relates to a sensor, a measuring device, and a method for analysing particles in fluids. By means of the method, an inline analysis of particles, in particular plastic particles, is possible for the first time. Measurement data is detected by a sensor which is specially designed for this purpose and can be connected to a measuring device provided for the method. The method, the sensor and the measuring device can be used to continuously detect impurities in a fluid flow. The method for detecting and analysing individual particles in fluids is carried out by means of electrical impedance spectroscopy in the flow.

Description

[0001] SENSOR, MEASURING DEVICE, METHOD AND USE FOR THE ANALYSIS OF PARTICLES IN FLUIDS

[0002] Description

[0003] The present invention relates to a sensor, a measuring device and a method for analyzing particles in fluids. This method enables inline analysis of particles, in particular plastic particles, for the first time. The measurement data is acquired by a sensor specially designed for this purpose, which can be connected to a measuring device provided for the method. With the help of the method, the sensor and the measuring device, contaminants in a fluid stream, which advantageously flows through the sensor, can be continuously detected. The method for detecting and analyzing individual particles in fluids is implemented using electrical impedance spectroscopy in the flow.

[0004] background

[0005] The analysis of particles in fluids plays a significant role today, particularly in scientific, medical, and industrial applications. This allows the quality of the fluids being examined to be analyzed and ensured at all times. In reality, fluids are often not in their pure form, but can contain foreign substances that may have entered a fluid as a result of a manufacturing process, for example. In order to always meet the highest safety and quality standards, it is essential to examine fluids as precisely and comprehensively as possible for possible, unwanted foreign substances, such as microplastic particles, and to constantly monitor them.

[0006] State of the art

[0007] Previous methods for particle analysis are associated with various limitations, such as complex and manual sample preparation, limited throughput, high time expenditure, and uncertainties in particle detection in turbid and / or contaminated fluids. In particular, the detection of particles and the simultaneous characterization of the various properties of the detected particles represents a major metrological challenge. Conventional methods are designed only to detect the presence of particles and, at best, to determine their number.

[0008] US 11 506 591 B2 describes a system and a method for distinguishing between plastic and non-plastic particles which are suspended in a liquid. The system has a channel to enclose the liquid and feed it to a detector. The detector comprises at least one signal electrode to send an electrical current to at least one receiving electrode. A circuit provides the measuring capacitances for the current input and the received electrical signals. Particles which pass through the receiving electrodes change the received electrical current in accordance with the dielectric properties of the particles, with the circuit recording the received signals and distinguishing the particles as plastic and non-plastic. The disadvantage here is that with this system and method only a binary classification of particles is possible, namely only as plastic or not plastic.Further classifications are not possible, but are often essential for practical use. Furthermore, this system can only be used to examine comparatively low liquid flows in the range of 0.001-1 liter / min, whereas industrial applications require higher volume flows.

[0009] Conventional sensors used for electrical impedance spectroscopy are not specifically designed for the detection of particles in fluids. The consequence of an unfavorable sensor design is low sensitivity combined with a very narrow measuring range. They also cannot be used to analyze high fluid flows for the presence of particles, as only very small and slow fluid flows can currently be analyzed.

[0010] Task

[0011] It is therefore an object of the invention to provide a sensor, a measuring device and a method which overcomes the disadvantages of the prior art and is suitable for detecting particles in fluids, wherein high fluid flows can be examined for particles in real time and at the same time the detected particles can be classified according to different properties.

[0012] Solution

[0013] The task is performed by a sensor with the characteristics according to

[0014] Patent claim 1 is solved. What is described here is a sensor for analyzing particles in a fluid, comprising at least one tube for conducting a fluid flow, on the inside of which at least one signal electrode is provided and on the outside of which an external shield is provided for electromagnetically shielding all components within the sensor against external interference signals, further comprising at least one receiving electrode, at least one electrode shield and at least one device for fluid displacement in the direction of at least one signal electrode and / or at least one receiving electrode.

[0015] The sensor design presented here directs the fluid within the sensor to create an environment optimized for particle measurement. The at least one fluid displacement device thus moves the fluid containing the particles as close as possible to the at least one signal electrode and / or at least one receiving electrode. At the same time, a laminar flow is created within the sensor. This results in a particularly high sensor sensitivity compared to conventional pipe flow.

[0016] Further advantageous embodiments are disclosed in the subclaims.

[0017] The sensor described here is particularly advantageously designed as a flow sensor. This advantageously means that fluid is not held stationary in the sensor, but that the fluid flows through the sensor and exits it again. The sensor can therefore also be referred to as an inline sensor. This is particularly advantageous so that at least partially a laminar flow of the fluid stream develops, advantageously between the device for fluid displacement and the inside of the pipe and / or between the device for fluid displacement and the at least one signal electrode and / or between the device for fluid displacement and the at least one receiving electrode.In addition, measurements can be taken quickly and effectively, as the fluid containing the particles flows through the sensor, thus advantageously entering at least one side and exiting the sensor again at least one side, so that at least one fluid flow is formed within the sensor. This also allows for the first time to implement continuous measurements for quality control, and corresponding trends can be read off.

[0018] The sensitivity as well as the temporal resolution of the measuring hardware and the sensor design influence the resolution of the particle measurement and its selectivity . The sensor unit , as the sensor can also be called, is optimized for sensitive particle detection at high volume flow . A high volume flow is assumed to be a volume flow greater than 1 liter / min . To increase the sensitivity of the sensor, the distance between the electrodes and the particles to be measured in the fluid is reduced or kept as small as technically possible . At the same time, the flow cross-section is kept as large as possible to ensure high volume flows, and the electric field is focused on the detection area , i.e. on the at least one signal electrode and the at least one receiving electrode . This occurs particularly with a serial electrode design or a segmentation of the electrodes, regardless of the electrode arrangement .Measurement hardware refers to all components connected to the sensor to perform electrical impedance spectroscopy. These include, for example, a potentiostat, an impedance analyzer, and a

[0019] ammeter, a voltmeter, an oscilloscope and / or a function generator and / or combinations thereof.

[0020] The electrodes, i.e. the at least one signal electrode and the at least one receiving electrode, are required in order to be able to carry out electrical impedance spectroscopy with the sensor. For this purpose, an electrical signal is applied to the at least one signal electrode and the signal response is measured at the at least one receiving electrode at the same time. Depending on the fluid and any particles it may contain, a specific signal response always results, which can be detected with the at least one signal electrode. For example, the signal responses differ between the pure fluid flow and the fluid flow with particles transported therein.

[0021] In a further advantageous embodiment, the tube of the sensor can have different geometries. For example, a round cross-sectional shape or a rectangular cross-sectional shape is conceivable. In the latter embodiment, the sensor is a so-called planar sensor. In a planar sensor, the electric field between the at least one signal electrode and the at least one receiving electrode is homogeneous with parallel field lines that run perpendicular to the flow direction of the fluid in the sensor. This allows particularly precise measurements to be carried out under easily controllable boundary conditions. In addition, the production of such sensors with a rectangular cross-sectional shape is simpler and therefore also more cost-effective. A sensor with a rectangular cross-sectional shape can advantageously be produced, for example, using thick-film technology.It is also conceivable that the sensor could be manufactured using 3D printing, by hand, or even using thin-film technology. In addition, a rectangular cross-sectional shape can create a large cross-section for high volume flows while still ensuring a small detection volume in terms of high selectivity and measurement accuracy. For this purpose, a small ratio of the short to the long side of the rectangular cross-sectional shape of the tube can be selected, advantageously with segmented electrodes. A ratio of the short side to the long side of less than 1:3 is advantageous, less than 1:5 is more advantageous, less than 1:10 is even more advantageous, and 1:15 is particularly advantageous. Ratios between 1:3 and 1:20 and / or 0.33 and 0.05 are also conceivable.Such a sensor design with a small aspect ratio is advantageous for applications in measuring devices or, more generally, in systems where particle analysis in a fluid is to be performed, where flat components are desired. This allows for simple and effective integration of such a sensor. This also includes sensors with a cross-section that is at least partially rectangular.

[0022] In contrast, sensors with a round cross-section are compact and less flat. This is advantageous for applications in measuring devices or, more generally, in systems where particles in a fluid are to be analyzed and where the sensor should simultaneously take up as little space as possible. This results in particularly simple and effective sensor integration. In the case of a sensor with a tube with a round cross-section, the sensor can also be referred to as having a cylindrical design or a cylindrical shape. This also includes sensors with a cross-section that is at least partially round.

[0023] This is, of course, not to be understood as limiting; it is also conceivable, for example, for the sensor to have a square cross-section, at least in some sections. This is advantageous because it allows for a cost-effective sensor design in terms of manufacturing technology.

[0024] This is, of course, not to be understood as limiting; it is also conceivable for a sensor to have multiple, different cross-sections. For example, to optimize flow, a sensor can initially have a round cross-section, which can then be converted into a rectangular or square cross-section, and / or vice versa.

[0025] It is also conceivable for a sensor to have more than two cross-sectional changes, for example, from round to square to round. This is advantageous because the first cross-sectional change from round to square simultaneously displaces the fluid flowing through the sensor, and the impedance measurement is performed in the square section.

[0026] In a further advantageous embodiment, all cables and connectors leading to the sensor can be shielded. Coaxial cables are particularly advantageous in this case. This prevents external interference signals that could falsify or disrupt the sensor's measurements. A short circuit of the coaxial cable shields as close as possible to the at least one signal electrode and / or the at least one receiving electrode proves particularly advantageous. This short circuit eliminates potential differences between the coaxial cable shields, prevents antenna effects, reduces common-mode currents, and improves the shielding effect of the entire system. This effectively minimizes high-frequency interference and significantly improves signal quality above 1 MHz.

[0027] A fluid displacement device can advantageously be understood as any means suitable for at least partially displacing the flow direction of at least one fluid stream entering and flowing through the sensor. "Displacing" can advantageously also be understood as deflecting, redirecting, or the like.

[0028] It is particularly advantageous, for example, for at least one inner side of a pipe to be designed as a device for fluid displacement. This is the case, for example, when the cross-section of the pipe changes along its longitudinal course. For example, it is conceivable for the pipe cross-section to change from round to rectangular. As a result of this change in cross-section, the at least one fluid stream flowing through the pipe is displaced at least in section and converted into the changed cross-section. Consequently, one can also speak of a shaping and deflection of the at least one fluid stream, which is achieved by the device for fluid displacement. In a particularly advantageous embodiment, it has proven advantageous if the cross-section change is from round to square. In this way, flow turbulence can advantageously be avoided and, at the same time, a cost-effective and highly sensitive electrode arrangement can be realized.It is conceivable that the pipe is initially cylindrical, undergoes a geometric change in a transition region, and then results in a cuboid. Fluid displacement in one direction includes both the movement of the fluid and the steering of all particles contained therein, since these are inextricably linked to the fluid flow. A change in the cross-section of the channel, for example, from round to rectangular or square, is an integral part of fluid displacement, as it shapes and redirects the flow in a targeted manner.

[0029] In a further advantageous embodiment of the sensor, the at least one signal electrode is segmented, so that it is divided into several independent signal electrodes, with a shield provided between each of these. This is advantageous because the shields separate the segments, i.e., the resulting independent signal electrodes. The shields ensure that the signal electrodes do not influence or interfere with each other.

[0030] The segmentation of the signal electrode has the advantage that, instead of one large volume, several small measuring volumes can be examined in parallel, thereby increasing sensitivity. These are also referred to as different measuring channels or detection areas. The segmentation therefore advantageously allows measurements to be taken simultaneously on several different measuring channels and in several different detection areas. The shielding between the individual signal electrodes, i.e. between the individual segments, in a passive or active design ensures that the signals from the individual measuring channels do not interfere with one another, thus leading to better measuring results. The measuring channels are electromagnetically separated so that they do not adversely overlap. Is actively shielded, i.e.The shielding electrode, as the shielding can also be called, is placed at the same potential as the signal electrodes, the so-called fringe effect can be reduced.

[0031] A further advantage of segmenting the signal electrode is that the respective detection area per segmentation or per measuring channel is reduced compared to a single, large signal electrode. By segmenting perpendicular to the flow direction within the pipe, the sensitivity and selectivity of the sensor with respect to particles in the fluid flow are greatly increased, since the detection area per measuring channel is reduced. The shields, which can be made of metal, for example, between the individual segmentations of the at least one signal electrode and / or between the individual measuring channels can be passive or active.

[0032] In a further advantageous embodiment of the sensor, the at least one receiving electrode is designed as a single electrode or segmented with intermediate shielding. The advantage of a receiving electrode in the form of a single electrode is that it can be easily and robustly integrated into the sensor. On the other hand, several hardware units have to share one receiving electrode and mutual influences can occur that have to be compensated for by measurement technology. Hardware units are understood to be components of a measurement hardware that are suitable for receiving measurement signals from the sensor and, if necessary, processing them so that measured values ​​are ultimately obtained.

[0033] In the embodiment with a segmented receiving electrode, it is particularly advantageous if the same number of segments are provided as the signal electrode has individual segments. In this way, a segment of the receiving electrode is assigned to each segment of the signal electrode. Advantageously, a segment of the signal electrode is arranged opposite a segment of the receiving electrode. For particularly effective measurements, the geometric surface extent of the segments of the signal electrode is the same size as the opposite segments of the receiving electrode. Particularly advantageously, a segment of the signal electrode forms a measuring channel with the opposite segment of the receiving electrode. This measuring channel is advantageously delimited laterally by four shields.

[0034] The segments can be arranged perpendicular to the direction of flow of the fluid or one behind the other parallel to the direction of flow of the fluid. The matching number of segments of the signal electrode and receiving electrode ensures a particularly high level of sensitivity of the sensor. This makes measured value recording by the measuring hardware simple and at the same time very precise. The segmentation of the receiving electrode means that the individual hardware units of the measuring hardware can record measured values ​​decoupled from one another without influencing or interfering with one another. This allows the measurement to be carried out in parallel, thereby increasing the sensitivity of the sensor because a smaller detection volume is available for each measuring channel provided. In addition, measurements can be carried out more quickly because several measuring channels can be recorded in parallel at the same time.Multiple hardware units do not have to share a single receiving electrode, as would be the case with a single-electrode design.

[0035] With a receiving electrode as a single electrode, the metrological setup for recording measurement signals on the measurement hardware side would be more complex in order to achieve equivalent results as with a segmented receiving electrode. This is not to be understood as a limitation; it is therefore also conceivable for the signal electrode to be designed as a single electrode and the receiving electrode as a segmented electrode. In this way, a single measurement signal emitted by the signal electrode can be recorded by the segmented receiving electrode. A measurement signal emitted individually can thus be measured in parallel by several individual electrodes, as the segments can also be called, namely the segmented receiving electrode. In this way, the parallel recording of the measurement signal via the segmented receiving electrode can, for example, be used to achieve local resolution of particles in a fluid flow.

[0036] In a further advantageous embodiment of the sensor, the at least one electrode shield is designed to be active or passive. This allows for a high degree of flexibility. In the passive design of the electrode shield, the shielding surfaces, which are made of an electrically conductive material such as metal, are grounded. This shields the individual electrodes, which are advantageously arranged between them, from one another, preventing them from influencing one another.

[0037] In the active embodiment of the electrode shielding, the shielding electrodes are set to the same potential as the receiving electrode or the signal electrode. This means that there are fewer, advantageously no, edge effects of the electric field at the edge of the electrodes. The field is therefore more uniform and there are fewer deviations in the measurement and / or detection signals. In an advantageous embodiment of the sensor, provision is made for the at least one signal electrode and the at least one receiving electrode to be arranged perpendicular to the direction of flow and at the same time opposite one another. This creates a particularly homogeneous electric field between the at least one signal electrode and the at least one receiving electrode, which is advantageous with regard to the sensitivity of the sensor. This allows individual particles in the fluid to be detected and characterized particularly precisely.Opposing electrodes enable high sensor sensitivity due to the parallel field lines of the electric field. Constant boundary conditions, including a homogeneous electric field, allow for more stable measurements, as fewer variations in the measurement signal occur during particle detection.

[0038] In a further advantageous embodiment, a distinction is advantageously made between two types of shielding: the overall shielding of the system, i.e. of the sensor, against external influences, such as coupling of the mains frequency, etc., on the one hand, and the shielding between the electrodes on the other.

[0039] The entire shielding is always grounded. The electrode shielding, which can be arranged axially and / or radially between the segmented electrodes, can be operated passively or actively, as explained above. Passive means that the shields are grounded, thus shielding the individual electrodes from each other, so that they do not influence each other.

[0040] Active means advantageous: the shielding electrodes are actively set to the same potential as the electrode they are shielding. This means that the shielding of the signal electrode is set to the potential of the signal electrode, and the shielding of the receiving electrode is set to the potential of the receiving electrode. This results in little or no "bulging" of the electric field at the edge of the electrode, which is known as the fringe effect. Thus, the field is more uniform, and there are fewer deviations in the measurement and / or defect ion signals.

[0041] In a further advantageous embodiment of the sensor, provision is made for the at least one signal electrode and the at least one receiving electrode to be arranged in series in the direction of flow. In this case, serial arrangement means that the at least one signal electrode and the at least one receiving electrode are arranged one behind the other in the direction of flow of the fluid. Although such an arrangement compromises the uniformity of the electric field and, consequently, the sensitivity of the sensor, it allows for simpler production. This not only saves production costs but also accelerates sensor production. In addition, the serial arrangement of the electrodes advantageously permits large pipe cross-sections and thus a high fluid flow rate. The serial arrangement of the electrodes therefore has economic advantages.An opposing arrangement of the electrodes, on the other hand, is associated with metrological advantages in terms of sensitivity and accuracy of the sensor, although it is at the same time more complex to manufacture.

[0042] In a further advantageous embodiment of the sensor, the tube, which is provided with at least one electrically insulating coating, is made of metal. This at least one coating is particularly advantageously provided on the inside of the tube, through which the fluid with the particles carried therein also flows. The at least one signal electrode and / or the at least one receiving electrode can be fixed, for example glued, to the coating of the tube. The electrodes thus advantageously form steps on the inside of the tube, which can optionally represent means for displacing the fluid. By making the tube out of metal, particularly inexpensive, quick and simple production of the sensor can be guaranteed. At the same time, the tube itself can function as external shielding, thus eliminating the need for separate external shielding.

[0043] In a further advantageous embodiment of the sensor, it is provided that the tube is made of an electrically insulating material, in particular plastic, synthetic resin, ceramic and / or glass, into which the at least one signal electrode and / or at least one receiving electrode and / or at least one electrode shield is embedded or cast. This can be done completely and / or partially. As a result, the at least one signal electrode and the at least one receiving electrode are permanently and firmly positioned.

[0044] Advantageously, and in order to avoid additional turbulence in the fluid flow, the at least one signal electrode and also the at least one receiving electrode can be embedded in the inner surface of the pipe so that they are flush with the inner surface of the pipe. This transition from sensor to pipe is advantageously designed as a seamless transition. This ensures that no turbulence or deposits of dirt can occur at the transition from pipe material to the electrodes, which could falsify the measurement result. Furthermore, the direct contact of the electrodes with the medium enables measurement with maximum sensitivity. During production, the electrodes are positioned on a pipe before casting, for example by press fitting. This pipe is drilled out after casting, which ensures a seamless transition between the electrodes and the pipe material.This ensures precise and seamless positioning of the electrodes right from the start.

[0045] In a further advantageous embodiment of the sensor, the at least one signal electrode and the at least one receiving electrode are cast into the pipe material in such a way that there is no direct contact between the electrodes and the medium. This means that no particles or contaminants can accumulate on the electrodes and distort the sensor’s measurement results. This means that measurement values ​​of consistent quality can always be guaranteed, even though casting the electrodes comes at the expense of the sensor’s sensitivity. Experience has shown that losses in sensitivity are within acceptable limits and can even be compensated for with suitable measuring hardware and / or corresponding measurement signal amplification. During production, the electrodes are press-fitted onto a pipe before casting. This pipe is drilled out after casting, so that a protective layer of pipe material remains above the electrodes.This ensures that the electrodes are positioned precisely and embedded securely right from the start.

[0046] In a further advantageous embodiment of the sensor, the at least one device for fluid displacement is a flow body in the center of the pipe, so that an annular gap is formed as the flow cross-section. The larger the radii of the annular gap, the closer the radii can be to one another while maintaining the same area. This means that a high volume flow can be ensured within the pipe and, at the same time, the electrodes, i.e. the at least one signal electrode and the at least one receiving electrode, can be located very close to one another, which increases the overall sensitivity of the sensor, particularly in combination with a serial or segmented design of the electrodes.

[0047] Furthermore, the detection area becomes more precise, since the larger the annular gap radius, the less fluid containing any particles flows past per electrode area. The flow cross-section is kept as large as possible, and the electric field of the electrodes is focused on the detection area. This enables sensitive particle detection with a simultaneous high volume flow.

[0048] In a further advantageous embodiment, the flow body is streamlined. Particularly advantageously, the geometry of the flow body corresponds to the mathematical formula where R o the thinnest

[0049] Diameter of the flow body, R is the thickest diameter of the flow body and L is the total length of the flow body. This formula describes the contour of the flow body along an x-axis, which is also rotationally symmetrical. The flow body is advantageously arranged centrally within the pipe, with an annular gap being formed between the inside of the pipe and the flow body. With the help of such a flow body, a laminar flow can advantageously be created within the annular gap, which in turn allows very precise measurement that is not disturbed by any turbulence in the flow of the fluid. Turbulence has the disadvantageous property that the particles to be measured do not perform straight-line movements parallel to the flow direction within the flow of the fluid, which would make detection more difficult.At the same time, the flow body forces the flow, and thus also the particles moving with the fluid, against the inner wall of the pipe, close to the electrodes and thus into the area of ​​high electric field density, which increases the sensitivity of the sensor. This follows the principle: To increase the sensitivity and / or the sensitivity of the sensor, the distance between the electrodes and the particles in the fluid is reduced.

[0050] In a further advantageous embodiment of the sensor, it is provided that the at least one receiving electrode is arranged on the flow body, or that the flow body is made of metal and thus simultaneously serves as the at least one receiving electrode. The separate arrangement of at least one receiving electrode on the flow body is particularly suitable when the flow body itself is not made of metal. For example, the flow body can be made of plastic. This is cost-effective and quick to manufacture.

[0051] The design with the flow body as the receiving electrode itself is particularly advantageous in that no additional electrode needs to be applied to the flow body. Such a structure is simple and robust. Furthermore, it eliminates the need to provide and mount a separate receiving electrode on the flow body, which reduces manufacturing costs and simultaneously shortens production time. It is also conceivable, for example, for a flow body to be made of plastic and coated with metal, so that the flow body itself can be used as a receiving electrode.

[0052] Furthermore, it is also conceivable for the flow body to be made of a non-electrically conductive material, thus having no sensory function and functioning solely as a device for fluid displacement. This also includes a body that causes a change in the cross-section of the channel, for example, from round to rectangular or square, since it shapes and redirects the flow in a targeted manner. Such a flow body is particularly advantageous in a serial electrode arrangement.

[0053] In a further advantageous embodiment of the sensor, the at least one device for fluid displacement is a hydrocyclone. This effectively pushes the fluid flow containing particles outwards into the sensitive area of ​​the serially arranged electrodes. At the same time, a hydrocyclone can separate the particles according to size and / or density. The different particle fractions can then be detected using separate sensors. This allows fluid-mechanical sorting of the particles to be measured in the fluid. Sensors of varying sensitivity, each optimized for the particles to be measured, can then be used for the separated particles. This makes it possible to make the measurement result more precise and / or more sensitive.

[0054] In a further advantageous embodiment of the hydrocyclone, it can advantageously have two sensors arranged thereon. In the simplest case, the two sensors are arranged upstream and / or downstream of the hydrocyclone. The hydrocyclone can also advantageously have a funnel shape, wherein a lateral inlet nozzle can be provided on the side with the greater width. Fluid containing particles can be introduced into the interior of the hydrocyclone through this inlet nozzle. Due to the lateral arrangement of the inlet nozzle and the funnel shape of the hydrocyclone which tapers on one side, a vortex forms in the interior which carries the particles in the fluid against the wall.

[0055] At the inlet of the hydrocyclone, i.e., at the side inlet nozzle, a primary vortex begins to form, which is guided toward the taper. As a result, particles introduced with the fluid are guided against the outer wall of the hydrocyclone and pressed against it, creating a particle enrichment on the wall.

[0056] Furthermore, particles are pushed out of the so-called underflow in the direction of the taper and from there reach a first sensor.

[0057] At the same time, a secondary vortex forms in the middle of the hydrocyclone interior, opposite to the primary vortex. This secondary vortex leaves the hydrocyclone via the so-called overflow and enters a second sensor. The fluid that is carried out of the hydrocyclone with the secondary vortex advantageously contains more lighter particles. The fluid in the primary vortex contains more heavier particles. The hydrocyclone thus separates heavy and light particles in the fluid flow so that they can each be measured in separate sensors. This means that the sensors can be optimally adapted to the separated particles and have different sensitivities.

[0058] In a further advantageous embodiment, the at least one device for fluid displacement is formed by the pipe itself. This is particularly advantageous since only one component needs to be provided here, which is cost-effective and maintenance-free. The displacement of the fluid then advantageously takes place by a change in the cross-section of the pipe, for example from round to rectangular or square. As a result of this change in cross-section, which advantageously takes place in a predeterminable transition, the fluid flowing through the pipe, together with the particles flowing therein, is at least partially displaced and deflected. The displacement advantageously takes place by the change in geometry in such a way that the fluid is displaced in the direction of the at least one signal electrode and / or in the direction of the at least one receiving electrode.

[0059] In a further advantageous embodiment of the sensor it is provided that the at least one device for fluid displacement is a swirl tube consisting of an S-curve directed in two axes. Such a design of a device for fluid displacement is particularly simple and robust and can be easily integrated. The fluid displacement takes place solely by predeterminable changes in direction of the fluid flow and requires no mechanical components. The two-fold deflection creates a swirl within the fluid flow, which presses the particles contained therein and to be measured outwards towards the inner wall of the tube of the sensor and thus in the direction of the at least one signal electrode and / or the at least one receiving electrode, which in turn increases the sensitivity. The surface of the swirl tube is advantageously structured in a spiral shape.

[0060] It is also conceivable for the fluid displacement device to be designed as a nozzle that directs the fluid flow toward the at least one signal electrode and / or the at least one receiving electrode. Here, the fluid displacement occurs through a cross-sectional change and / or cross-sectional tapering.

[0061] In general, when a homogeneous, particle-free fluid flows through the sensor, a stable and steady—i.e., time-independent—signal response is obtained. If at least one particle then passes through the sensor, the initially stable and steady-state signal response is altered. Based on this change, information about the particle's properties can be derived. Such information about the properties can include, for example, shape, size, material, and / or the number of particles.

[0062] The above-mentioned object is also achieved by a measuring device with the features according to patent claim 14. What is described here is a measuring device for analyzing particles in a fluid, comprising at least one sensor, as described above, at least one measuring unit for signal generation and supply to the sensor and at the same time for recording the signal response of the sensor and making this available as measured data, wherein the measuring unit has at least one data interface for exchanging measured data with at least one computer, and optionally at least one computer for processing measured data with at least one means for data output, with which the processed measured data can be output. The sensor is electrically conductively connected to the at least one measuring unit, wherein all connections are advantageously shielded.For this purpose, electrical connections can be provided via plugs and circuit boards and / or plugs and cables, each of which is advantageously shielded. This prevents external interference that could negatively influence the measurements with the sensor. The measuring unit can also be referred to as measuring hardware, which in turn consists of at least one hardware unit that is at least designed to record measured values. The measuring device as a whole makes it possible to use the sensor described above as intended and to carry out an analysis of particles in fluids.

[0063] The at least one means of data output can be, for example, a screen on which the processed measurement data can be graphically displayed. A data interface, such as an API, is also conceivable, through which the measurement data is provided for further computer processing.

[0064] In addition, it is also conceivable that several measuring devices supply data via suitable interfaces, even simultaneously, which are at least recorded, stored, processed and / or forwarded by a processing unit.

[0065] In a further advantageous embodiment of the measuring device, it is provided that the at least one computer, which can also advantageously be understood as a processing unit, has at least one communication interface for exchanging data with a computer network. Such a computer network can consist locally of at least one further computer. However, it is also conceivable for such a computer network to consist of several computers networked with one another. This also includes, for example, a cloud service on the Internet in which the measurement data is transmitted to at least one server via the at least one communication interface. In this way, the server can, for example, further process the transmitted measurement data and make it available via a further data output.

[0066] The above-mentioned object is finally also achieved by a method with the features according to patent claim 16. What is described here is a method for particle detection using a measuring device as described above, with at least one sensor, as also described above, with at least the following steps: flowing a fluid through the sensor, wherein the at least one device for fluid displacement directs the fluid flowing through the sensor in the direction of at least one signal electrode and / or at least one receiving electrode; applying an electric field to the at least one signal electrode or simultaneously applying a plurality of individual fields, each with the same properties, with a frequency band in the range of 0-30 MHz predetermined by the measuring device;

[0067] Measuring the electric field or fields at the at least one receiving electrode, whereby analog measurement data are obtained;

[0068] Converting the analog measurement data into digital measurement data using an A / D converter within the measuring device;

[0069] Transmitting the digital measurement data via the data interface to the computer; processing the measurement data by the computer or sending the measurement data via the communication interface to a computer network, such as to another computer in a local computer network or to a cloud service on the Internet, and processing the measurement data there and sending the processed measurement data back to the computer, wherein the processing of the measurement data is a classification of the measurement data into number, size, material and / or shape of particles in the fluid using a machine learning algorithm, for example a support vector machine or neural network; and data output of the processed measurement data, wherein the measurement data is output according to its classification.

[0070] The type of data output is not restricted and can be carried out as described above. In general, data output means making classified measurement data available. This type of data output can also be used to carry out control or regulation processes. The measurement data obtained can be used to control and / or regulate industrial production processes, for example. Classification can be based on the number of particles, particle material, particle shape and particle size, for example. Other characteristic features of a particle can also be determined and classified.

[0071] The measuring range of the sensor, i.e. the frequencies that can be predefined by the measuring device, is usually in the range from 20 Hz to 5 MHz. However, the range can be extended up to 20 MHz. A maximum of 30 MHz is provided. In this case, 16 different

[0072] frequencies are measured simultaneously on the sensor. These

[0073] However, the number is not limiting, so more parallel frequencies are also possible. The measuring device and / or the measuring hardware must be expanded accordingly to enable simultaneous measurements on multiple measurement channels. Individual frequencies can be used advantageously.

[0074] The present invention relates to an advanced method for particle analysis in flowing fluids, which is carried out by means of electrical impedance spectroscopy (EIS), in combination with artificial intelligence (AI) for the evaluation and classification of measurement data recorded by a sensor and containing information on particles in the fluid or fluid flow to be measured. AI includes so-called machine learning (ML), which in turn includes various methods, such as decision trees, k-nearest neighbors (kNN), support vector machines (SVM) or artificial neural networks (ANN, CNN). Another special form of machine learning is so-called deep learning, such as deep neural networks (DNN).

[0075] A key aspect of the method is, in addition to the acquisition of measurement data via the sensor using electrical impedance spectroscopy, the processing and / or evaluation of the measurement data. This can be done locally on the computer, in a network or computer network, or via the Internet using a cloud service. When processing the measurement data, peak detection is first performed. If a particle in the fluid passes the sensor, a peak is generated in the measurement data, which indicates the presence of the particle. The peak is caused by the disturbance of the electric field between the at least one

[0076] signal electrode and at least one receiver electrode, which is recorded by the electrodes and the measuring device. The interest is not in the absolute measured values, but rather the changes in the measured values ​​over time. This is done using what is known as peak detection. A search is carried out for fluctuations in the measured data that were caused by the presence of particles in the sensor. The peak in the measured data for a particle has a characteristic shape that depends on the shape, material and size of the particle. If necessary, this can also be used to detect several particles at the same time and determine their number. The analysis of the shape of the peaks leads to a classification according to the characteristic features of the particles in the fluid. The classification is carried out using what is known as artificial intelligence (AI), in particular machine learning, as already described above.The support vector machine method proved particularly precise in this regard. The algorithm was trained in advance using training data. Fluids containing defined particles were examined using the sensor, and the measured signals were linked to the characteristic properties of the particles used in the learning process. This allowed the algorithm to "learn" which characteristic properties of particles correspond to which peaks in the measurement data. The algorithm can be executed locally on a computer or outsourced to a cloud service via a computer network or the Internet.

[0077] Finally, the object mentioned at the outset is also achieved by the use of a sensor having the features according to at least one of patent claims 1 to 13 with a measuring device having the features according to patent claim 14 or 15 and a method having the features according to patent claim 16 for particle detection and for classifying particles in a fluid, wherein the classification is carried out at least in terms of the number of particles, material of the particles, shape of the particles and size of the particles. This makes it possible for the first time to carry out in-situ particle detection in a fluid stream, which detection takes place in real time and for fluid streams relevant in practice. Not only can a distinction be made between particles and no particles, but it is also possible to carry out a comprehensive characterization of detected particles at the same time, in particular with regard to their size, shape and material.

[0078] It is advantageous to use the terms shielding, intermediate shielding, shielding electrodes and electrode shielding synonymously.

[0079] Further advantages, features and design options emerge from the following description of non-limiting embodiments.

[0080] Brief description of the drawings

[0081] The drawings show:

[0082] Fig. 1a is a perspective view of a sensor with a cylindrical shape,

[0083] Fig. 1b is a plan view of the sensor from Fig. 1a with a section plane BB,

[0084] Fig. 1c is a sectional view of the section plane BB of the sensor of Fig. 1b with a signal electrode in a first embodiment,

[0085] Fig. Id is a sectional view of the section plane BB of the sensor from Fig. 1b with a signal electrode in a second embodiment,

[0086] Fig. le is a frontal view of the sensor from Fig. la with a section plane AA,

[0087] Fig. 1 f is a sectional view of the section plane AA of the sensor from Fig. 1e, Fig. 1g is a flow body with a separate receiving electrode as a ring,

[0088] Fig. 1h a receiving electrode as a ring,

[0089] Fig. li a receiving electrode as a segmented ring with intermediate shields,

[0090] Fig. 2a is a perspective view of another embodiment of a sensor with a cylindrical shape,

[0091] Fig. 2b is a top view of the sensor from Fig. 2a with section planes AA, BB and CC,

[0092] Fig. 2c Sectional view AA of the sensor from Fig. 2b,

[0093] Fig. 2d Sectional view BB of the sensor from Fig. 2b and

[0094] Sectional view CC of the sensor from Fig. 2b,

[0095] Fig. 3a is a perspective view of the sensor with serial electrode arrangement and a device for hydrodynamic fluid displacement,

[0096] Fig. 3b is a side sectional view of the sensor with device for hydrodynamic fluid displacement from Fig. 3a,

[0097] Fig. 4a is a perspective view of a fluid displacement device as a hydrocyclone with two sensors arranged thereon,

[0098] Fig. 4b a side view of the hydrocyclone,

[0099] Fig. 4c is a side sectional view of the hydrocyclone,

[0100] Fig . 5 is a perspective view of another

[0101] Embodiment of a device for fluid displacement with a sensor arranged thereon,

[0102] Fig. 6a is a perspective view of a sensor in a planar embodiment with electrodes arranged perpendicular to the flow direction,

[0103] Fig. 6b is a frontal view of the sensor from Fig. 6a with sectional plane AA and BB, Fig. 6c is a sectional view in the sectional plane AA of the sensor from Fig. 6b with a signal electrode in a first embodiment,

[0104] Fig . 6d a detailed view from Fig . 6c,

[0105] Fig. 6e is a sectional view in the section plane BB of the sensor from Fig. 6b with a receiving electrode in a first embodiment,

[0106] Fig. 6f is a sectional view in the section plane BB of the sensor from Fig. 6b with a receiving electrode in a second embodiment,

[0107] Fig. 6g is a further sectional view of the sensor from Fig. 6a, Fig. 7a is a perspective view of a sensor in planar embodiment with serially arranged electrodes,

[0108] Fig. 7b is a frontal view of the sensor from Fig. 7a with a section plane AA,

[0109] Fig . 7c a sectional view in the section plane AA of the sensor from Fig . 7b,

[0110] Fig . 7d a detailed view from Fig . 7c,

[0111] Fig. 8 is a schematic diagram for operating a sensor,

[0112] Fig. 9 shows another schematic diagram for operating a sensor and

[0113] Fig. 10 is a flow chart of a measurement procedure.

[0114] In the drawings, elements provided with the same reference symbols essentially correspond to one another, unless otherwise stated. Furthermore, the drawings refrain from showing and describing components that are not essential to understanding the technical teaching disclosed herein. In the following, the reference symbols will not be repeated for all elements already introduced and illustrated, provided that the elements themselves and their function have already been described or are known to a person skilled in the art. Detailed description of exemplary embodiments

[0115] Fig. 1a shows a perspective view of a sensor 1 with a cylindrical shape. The sensor 1 has a tube 2, around the outer radius of which an outer shield 3 is arranged. This protects the interior of the sensor 1 from external electromagnetic fields. The outer shield 3 is advantageously made of metal. In the present embodiment, it is designed as a metal sleeve. The outer shield 3 has a plurality of cutouts on its circumference. These cutouts are contact points, in particular two contact points 4 for two shielding electrodes 13, two contact points 5 for a receiving electrode 11 and at least two contact points 6 for the at least one signal electrode 8; 10.

[0116] Fig. 1b shows a plan view of the sensor 1, as shown in Fig. 1a, with a sectional plane BB running transversely to the longitudinal extent, wherein Fig. 1c and Fig. 1d each show a sectional view of the sectional plane BB in two different embodiments of the sensor 1. In Fig. 1c, a signal electrode 8 is shown as a segmented ring, with shields 9 arranged between the segments. In a further example, Fig. 1d shows a sectional view of a signal electrode 10 in the form of a single ring. This signal electrode 10 has no interruptions or segmentations along its circumference and is formed in one piece. Furthermore, both Fig. 1c and Fig. 1d show the rotationally symmetrical structure of the embodiment of the sensor 1 shown. A flow body 12 is arranged in the center of the respective sensor 1.Concentrically around it is formed an annular flow channel 7, which is bounded by the pipe 2. Concentrically around the outside of the pipe 2 is the...

[0117] External shielding 3 arranged .

[0118] Fig. 1e shows a front view of the sensor 1, as shown in Fig. 1a, with a sectional plane AA perpendicular through the sensor 1 and along its longitudinal extent. The arrangement of the internal components of the sensor 1 can also be seen in the front view, as already shown in Fig. 1c and Fig. 1d, namely in the middle of the flow body 12. Concentric to this, the tube 2 with the signal electrode 10 embedded therein (not explicitly shown here) is arranged, so that an annular flow channel 7 is formed between the flow body 12 and the tube 2. The outer shielding 3 is also provided on the outside around the tube 2.

[0119] Fig. 1 f shows a sectional view of the section plane AA of the sensor 1, as shown in Fig. 1e. It shows a longitudinal section through the tube 2, in the middle of which a peg-shaped flow body 12 is arranged. At its two outer ends, at the front and at the rear, there is a contact point 5 of the receiving electrode 11, the flow body 12 in the embodiment shown simultaneously being the receiving electrode 11 and also being held in position by the contact points 5. The annular flow channel 7, through which a fluid can flow, is formed between the tube 2 and the flow body 12. Advantageously, the fluid also carries particles for detection.

[0120] Furthermore, two annular, axial shielding electrodes 13 are embedded in the tube 2. They each have a contact point 4 of the shielding electrode 13, which is led outwards through the tube 2 and the outer shielding 3. The signal electrode 6 is arranged between the two shielding electrodes 13 and is also connected to the outside via contact points 6 at the top and bottom through the tube 2 and the outer shielding 3. Cables, advantageously shielded cables and / or coaxial cables, can be connected to the contact points 4, 5 and 6. The fluid enters the tube 2 from the left-hand side and strikes the flow body 12, which at the same time displaces the fluid. The fluid is thus deflected and flows through the resulting annular flow channel 7, where the measurement of the particles entrained in the fluid takes place. As it continues to the right, the fluid then exits the tube 2 again.The fluid thus flows through pipe 2.

[0121] Fig. 1g shows another flow body 12 with a separate receiving electrode 13 in the form of an electrically conductive ring 14, which is slid centrally and concentrically onto the flow body 12. It is conceivable that the flow body 12 is not made of metal, and only the receiving electrode, as a ring 14, is made of metal. However, this is only optional and represents one of many possible embodiments.

[0122] In Fig. 1h, a further embodiment of the receiving electrode is shown as a ring 14. In Fig. 1i, a further embodiment of the receiving electrode is shown as a segmented ring 15, with intermediate shields 16 arranged between the segments.

[0123] Fig. 2a shows a perspective view of a further embodiment of a sensor 1 with a cylindrical shape. It is similar to the first embodiment shown in Fig. 1a, whereby the connections of the electrodes, i.e. the contact points 4, 5 and 6, are not identical. This is due to a serial arrangement of the electrodes inside the sensor 1. Furthermore, the sensor 1, as already explained, has a tube 2, on the outer circumference of which an outer shield 3 is arranged, wherein the outer shield 3 has recesses for the contact points 4, 5 and 6.

[0124] Fig. 2b shows a top view of the sensor 1 from Fig. 2a with the section planes AA, BB and CC, where the section plane AA runs centrally along the sensor 1 and the section planes BB and CC run transversely to the longitudinal extent of the sensor 1. Here, according to the top view, the contact points 4, 5 and 6 can be seen from above.

[0125] Fig. 2c shows the sectional view AA of the sensor 1 from Fig. 2b, showing a central longitudinal section of the sensor 1. This view corresponds to the view in Fig. 1f, except for a few differences. An outer shield 3 is provided on the outside, wherein the outer shield 3 has recesses through which the contact points 4, 5 and 6 protrude and provide a connection to the corresponding electrodes inside the sensor 1. The tube 2 is arranged concentrically to the outer shield 3. Two shielding electrodes 13 are embedded in the tube 2. A flow body 12 is arranged in the center of the tube 2. The flow body 12 can be provided here as a pure displacement element for the fluid, i.e. as a device for fluid displacement, within the tube 2.

[0126] In addition, in the embodiment shown in Fig. 2c, a separate receiving electrode 11 and a signal electrode 8; 10 are provided, wherein the signal electrode can be designed as a single ring 10 or as a segmented ring 8, as shown separately below in Fig. 2d. Also the

[0127] Receiving electrode 11 can be designed in different ways. Fig. 2d shows, on the one hand, a sectional view BB of the sensor 1 from Fig. 2b and, on the other hand, a sectional view CC of the sensor 1 from Fig. 2b in various variants. On the left side, the sectional view BB is shown and on the right side the sectional view CC. The rows from top to bottom each show a possible variant of how the different embodiments of signal electrode 8; 10 and receiving electrode 14; 15 can be combined with one another and provided in the sensor 1.

[0128] The first, upper row shows a variant with a signal electrode as a segmented ring 8 and a receiving electrode as a ring 14. The second, middle row below shows, on the left, a signal electrode as a segmented ring 8 and a receiving electrode, also as a segmented ring 15. The third and bottom row shows a variant in which both the signal electrode and the receiving electrode are each designed as individual rings 10, 14.

[0129] Fig. 3a shows a perspective view of the sensor 1 with a serial electrode arrangement and a device for hydrodynamic fluid displacement. The device for hydrodynamic fluid displacement has four lateral inlet nozzles 17 pointing radially outwards in a star shape and one axially arranged central inlet nozzle 18. Fig. 3b shows a sectional view of the sensor 1 with the device for hydrodynamic fluid displacement, as shown in Fig. 3a. Sampled medium 19, i.e. fluid with particles, is filled into the lateral inlet nozzles, and displacement fluid 20, i.e. fluid without particles, is filled into the central inlet nozzle 18. The displacement fluid 20 has the task of pressing the sampled medium 19 outwards towards the electrodes. This enables a sensitive measurement.The particles are thereby pressed against the inner pipe wall and pass very closely through the electrodes, allowing them to be easily detected by the electrodes. The displacement of the sampled medium 19 radially outward toward the inner pipe wall is facilitated by a diffuser 21.

[0130] Fig. 4a shows a perspective view of a device for fluid displacement in the form of a hydrocyclone 22 with two sensors 1 arranged thereon, which are each arranged at the front and rear of the hydrocyclone 22. As can be seen in Fig. 4b in the side view of the hydrocyclone 22, a sensor 1 is arranged on each side. The hydrocyclone 22 has an overall funnel shape, with a lateral inlet nozzle 17 being provided on the side with the greatest width, through which fluid with particles can be introduced. Due to the lateral arrangement of the inlet nozzle 17 and the tapered funnel shape of the hydrocyclone 22, a vortex forms in the interior which presses the particles in the fluid against the outer wall. Fig. 4c shows a lateral sectional view of the hydrocyclone 22, where the funnel shape tapering towards the underflow 24 can be seen.At the inlet of the hydrocyclone 22, i.e. at the lateral inlet nozzle 17, a primary vortex forms which is pushed to the right in the image. As a result, particles in the fluid are pushed against the outer wall of the hydrocyclone 22 and accumulate there. They are pushed to the right out of the so-called underflow 24 and there reach a first sensor 1. At the same time, in the middle of the hydrocyclone 22, a secondary vortex opposite to the primary vortex forms. This secondary vortex leaves the hydrocyclone 22 to the left via the so-called overflow 23 and there enters a second sensor 1. The fluid which is channeled out of the hydrocyclone 22 with the secondary vortex contains an increased number of lighter particles. The fluid in the primary vortex contains an increased number of heavier particles. The hydrocyclone 22 separates heavy and light particles so that they can each be measured in separate sensors 1.Thus, the sensors 1 can each be optimally adapted to the separated particles and have different sensitivities.

[0131] Fig. 5 shows a perspective view of another embodiment of a device for fluid displacement with a sensor 1 arranged thereon. The device for fluid displacement is designed as a double-S curve 25, i.e., it forms an S curve directed along two axes and thereby spans a double-S-shaped, wound tubular body. Due to the double deflection of the fluid inside, the flow is pressed against the inner wall of the sensor 1, which results in greater sensitivity.

[0132] Fig. 6a shows a perspective view of a sensor 1 in a planar embodiment with electrodes arranged perpendicular to the flow direction. The structure corresponds in principle to the structure of a sensor 1 as shown, for example, in Fig. 1a, but with the difference that a rectangular cross-sectional shape has been chosen instead of a round one. This results in a narrow distance between the signal electrode and the receiving electrode (not shown here) with a simultaneous high volume flow. Round connection pieces are provided at the two outer ends of the sensor 1 in order to connect them to pipes or hoses. An outer shield 3 with cutouts for contact points of the receiving electrode and the signal electrode 5, 6 forms the outer boundary of the sensor 1. In the embodiment shown, the cutouts are arranged equidistantly in the middle of the sensor 1 transversely to its longitudinal extent.Offset from this is a further recess for a contact point 4 for the shielding electrode (not shown). Directly beneath the outer shielding 3 there is a pipe 2 with a rectangular cross-section. The pipe is advantageously of flat, cuboid-shaped design and extends in the direction of flow of the fluid, i.e. greater in the longitudinal direction of the sensor 1 than in the vertically arranged vertical extension of the sensor. Between the connection piece and the center of the sensor with a rectangular cross-section there is a transition area where the shape changes smoothly from round to rectangular. In this way the fluid flowing in the sensor 1 is transferred turbulence-free from a round to a rectangular flow cross-section and back again. The change in cross-section and thus the pipe wall itself forms the device for fluid displacement.The fact that the fluid flow in the cuboid-shaped section of the sensor 1 always remains laminar is essential for the intended function of the sensor 1, since turbulence would lead to oscillating particles within the fluid and thus to incorrect measurement results. This transition region of the tube 2 can also be referred to as a device for fluid displacement, since it has the shape of a nozzle. This means that there is a change in cross-section, advantageously a cross-sectional tapering in the direction of flow. The shape of the nozzle has the effect that the fluid flow is directed in the direction of the at least one signal electrode and / or the at least one receiving electrode. When the fluid flows out of the sensor, the transition region functions as a diffuser, exactly the opposite of the nozzle.

[0133] Fig. 6b shows a frontal view of sensor 1 from Fig. 6a with the section planes AA and BB. This view clearly shows the round cross-section at the beginning and end of sensor 1, respectively, which transitions to a rectangular cross-section in the middle. Fig. 6c and Fig. 6e are almost identical, differing only in that different electrodes are shown.

[0134] Fig. 6c shows a sectional view along section plane AA of sensor 1 from Fig. 6b with a signal electrode shown in a first embodiment, wherein the signal electrode 26 is segmented. This means that it is divided into several small signal electrodes, each forming different measurement channels. Fig. 6d shows a detailed view from Fig. 6c, specifically a portion of the segmented signal electrode 26, with an intermediate shield 9 arranged between each of them. The intermediate shield 9 increases the selectivity or sensitivity of the sensor 1 or the segmented signal electrode 24.

[0135] Fig. 6e shows a sectional view along section plane BB of sensor 1, as shown in Fig. 6b, with a receiving electrode 11 in a first embodiment, wherein the receiving electrode 11 is segmented. This means that it is divided into several small receiving electrodes. A shielding electrode 13 is arranged around the segmented receiving electrode 27. Fig. 6f shows a sectional view along section plane BB of the sensor 1 from Fig. 6b with a receiving electrode 11 in a second embodiment, wherein the receiving electrode 11 is designed as a single electrode without segmentation.

[0136] The embodiments from Fig. 6a to Fig. 6e have in common that the signal electrode and the receiving electrode are arranged opposite one another, thereby creating an electric field with field lines perpendicular to the direction of flow of the fluid with particles. This is illustrated again in Fig. 6g. This shows a sectional view perpendicular to the direction of flow of the fluid (not shown). Firstly, the tube 2 is shown in its rectangular cross-section. A segmented signal electrode 26 is arranged on the upper inside of the tube. Thus, five individual signal electrodes are shown here as an example. A shield 9 is arranged between each segment. Opposite this, on the lower inside of the tube, a segmented receiving electrode 27 is provided.The segments of the segmented receiving electrode 27 advantageously correspond, at least in terms of their geometric surface area, to the segments of the segmented signal electrode 26 lying above them and spaced apart across the fluid channel. The segments of the receiving electrode 27 are also spaced apart from one another by a respective shielding electrode 9; 13. This makes it possible to form the electric field with the field lines 34 shown. Individual detection regions D1 to D5 are advantageously formed by the respective shields 9; 13, which are advantageously arranged opposite one another and spaced apart from one another by the fluid channel. These prove to be advantageous because, by reducing the volume of fluid flowing through, a higher sensitivity per detection region D1 to D5 can be achieved. The embodiment shown here is therefore particularly effective and thus advantageous.

[0137] Fig. 7a shows a perspective view of a sensor 1 in a planar embodiment with serially arranged electrodes. The structure essentially corresponds to that of Fig. 6a. The only difference is the arrangement of the electrodes one behind the other. This also results in the

[0138] Electrodes the connections or contact points on other

[0139] places are positioned. This means that the outer shielding 3 also has corresponding cutouts at other locations. In the middle of the sensor 1 the tube 2 has a rectangular cross-sectional shape. Around this, an outer shielding 3 with a corresponding, rectangular cross-sectional shape is arranged like a belt. Perpendicular to the longitudinal extent of the sensor 1 there are two rows with a plurality of cutouts arranged equidistant from one another with contact points 5 and 6 of the receiving electrode and the signal electrode (both not shown here). In the embodiment shown both the signal electrode and the receiving electrode are segmented. Spaced from the two rows of cutouts there is a further cutout arranged in the middle and offset therefrom. This is the contact point 4 for the shielding electrode.

[0140] Fig. 7b shows a front view of the sensor 1 from Fig. 7a with a sectional plane AA. This view corresponds to the view from Fig. 6b. The following Fig. 7c shows a sectional view in the sectional plane AA of the sensor 1, as shown in Fig. 7b. This view also corresponds to that from Fig. 6c, but with the difference that two rows of electrodes are provided. In the present embodiment, the electrodes are arranged in series. This means that the segmented signal electrode 26 and the segmented receiving electrode 27 are arranged one behind the other along the flow direction, i.e. along the longitudinal extent of the sensor 1. A detailed view of this is shown in Fig. 7c. There it can also be seen that an intermediate shield 9 is provided between the individual segments in order to increase the selectivity or sensitivity of the sensor 1.A sectional view in the opposite direction to the section plane AA would show no electrodes. This also demonstrates the advantage of the present embodiment. The electrodes are located on only one side of the sensor 1, which, on the one hand, allows for simple production and, on the other hand, allows for easy integration into systems or measuring devices, since connections only need to be made to the sensor 1 from one side.

[0141] Fig. 8 shows a schematic diagram for the operation of a sensor 1 which is designed as a flow sensor. The structure is kept very simple: a fluid flows in a fluid line 29 and is pumped through the sensor 1 with the help of a pump 28. It is also conceivable to use gravity instead of a pump 28 to pump the fluid. In this regard, Fig. 9 shows a further schematic diagram for the operation of a sensor 1, wherein at the top there is a fluid container 30 with a fluid 32 located therein, from which a fluid line 29 extends downwards, to which a sensor 1 is connected. The fluid 32 flows down through the sensor 1 driven by gravity.

[0142] Finally, Fig. 10 shows a flow chart of a measurement method with an attached AI, which both processes and classifies the measurement data and is trained using the measurement data to ensure ever more precise processing of the measurement data. A database of labeled data is created, which can be used to train the algorithm (supervised learning). Preferably, the AI ​​is an artificial neural network or a support vector machine. However, this is not to be understood as limiting, so alternative AI algorithms can also be used to classify data. Reference symbol! List

[0143] 1 sensor

[0144] 2 pipes

[0145] 3 External shielding

[0146] 4 Contact point of the shielding electrode

[0147] 5 Contact point of the receiving electrode

[0148] 6 Contact point of the signal electrode

[0149] 7 annular flow channel / annular gap

[0150] 8 Signal electrode as segmented ring

[0151] 9 Intermediate shielding / shielding

[0152] 10 Signal electrode as a single ring

[0153] 11 Receiving electrode

[0154] 12 flow bodies

[0155] 13 Shielding electrode / electrode shielding

[0156] 14 Receiving electrode as a ring

[0157] 15 Receiving electrode as a segmented ring

[0158] 16 intermediate shields of the receiving electrode

[0159] 17 side inlet nozzle

[0160] 18 central inlet nozzle

[0161] 19 sampled medium

[0162] 20 displacement fluid

[0163] 21 Di f fusor

[0164] 22 Hydrocyclone

[0165] 23 Upper course

[0166] 24 Lower reaches

[0167] 25 Double S-curve

[0168] 26 segmented signal electrodes

[0169] 27 segmented receiving electrode

[0170] 28 Pump

[0171] 29 Fluid line

[0172] 30 fluid containers

[0173] 31 skimmers

[0174] 32 Fluid 34 Field lines

[0175] Dl detection range

[0176] D2 Detection range

[0177] D3 Detection range D4 Detection range

[0178] D5 Detection range

Claims

Patent claims 1. Sensor (1) for analyzing particles in a fluid (32), at least comprising a tube (2) for conducting a fluid flow, on the inside of which at least one signal electrode (8; 10) is provided and on the outside of which an external shield (3) is provided for electromagnetically shielding all components within the sensor (1) against external interference signals, further comprising at least one receiving electrode (11), at least one electrode shield (13) and at least one device for fluid displacement in the direction of at least one signal electrode (8; 10) and / or at least one receiving electrode (11).

2. Sensor (1) according to claim 1, characterized in that the at least one signal electrode (8) is segmented so that it is divided into several independent signal electrodes (8), with a shield (9) being provided between each of these.

3. Sensor (1) according to claim 1 or 2, characterized in that the at least one receiving electrode (11; 14; 15) is designed as a single electrode or segmented with an intermediate shield (16).

4. Sensor (1) according to claim 1, characterized in that the at least one electrode shield (13) is designed to be active or passive. i 5. Sensor (1) according to claim 1, characterized in that the at least one signal electrode (8; 10) and the at least one receiving electrode (11) are arranged perpendicular to the flow direction and at the same time opposite one another.

6. Sensor (1) according to claim 1, characterized in that the at least one signal electrode (8; 10; 26) and the at least one receiving electrode (11; 14; 15; 27) are arranged serially in the flow direction.

7. Sensor (1) according to claim 1, characterized in that the tube (2) is made of metal which is provided with at least one electrically insulating coating.

8. Sensor (1) according to claim 1, characterized in that the tube (2) is made of an electrically insulating material, in particular plastic, synthetic resin, ceramic and / or glass, in which the at least one signal electrode (8; 10) and / or at least one receiving electrode (11) and / or at least one electrode shield (13) is embedded or cast.

9. Sensor (1) according to claim 1, characterized in that the at least one device for fluid displacement is a flow body (12) in the center of the tube (2), so that an annular gap (7) is formed as the flow cross-section.

10. Sensor (1) according to claim 3 and 9, characterized in that the at least one receiving electrode (11; 14; 15) is arranged on the flow body (12) or that the flow body (12) is made of metal and thereby simultaneously is itself the at least one receiving electrode (11).

11. Sensor (1) according to claim 1, characterized in that the at least one device for fluid displacement is a hydrocyclone (22) or that the at least one device for fluid displacement is formed by the pipe (2) itself.

12. Sensor (1) according to claim 1, characterized in that the at least one device for fluid displacement has a geometry according to the following equation: with R o as the thinnest diameter of the flow body, R as the thickest diameter of the flow body and L as the total length of the flow body.

13. Sensor (1) according to claim 1, characterized in that the at least one device for fluid displacement is designed as a swirl tube.

14. Measuring device for the analysis of particles in a fluid (32) at least comprising a sensor (1) according to at least one of the preceding claims 1 to 13, at least one measuring unit for signal generation and supply to the sensor (1) and at the same time for recording the signal response of the sensor (1) and providing this as measurement data, wherein the measuring unit has at least one data interface for exchanging measurement data with at least one computer, and at least one computer for measurement data processing with at least one means for data output with which the processed measurement data can be output.

15. Measuring device according to claim 14, characterized in that the at least one computer has at least one communication interface for data exchange with a computer network.

16. A method for particle detection using a measuring device according to claim 14 or 15 with at least one sensor (1) according to claim 1 with at least the following steps: a) flowing a fluid (32) through the sensor (1) according to claim 1, wherein the at least one device for fluid displacement directs the flowing fluid (32) in the direction of at least one signal electrode (8; 10) and / or at least one receiving electrode (11; 14; 15); b) applying an electric field with a frequency range predetermined by the measuring device to the at least one signal electrode (8; 10) or simultaneously applying a plurality of individual fields, each with the same properties, with a frequency band predetermined by the measuring device in the range of 0-50 MHz; c) measuring the electric field or fields at the at least one receiving electrode (11; 14; 15), whereby analog measurement data are obtained;d) converting the analogue measurement data into digital measurement data using an A / D converter; e) transmitting the digital measurement data to the computer via the data interface; f) processing the measurement data by the computer or sending the measurement data to a computer network via the communication interface and processing the measurement data there and sending the processed measurement data back to the computer, whereby the processing of the measurement data includes a classification of the; Measurement data in number, size, material and / or shape of particles in the fluid (32) using a machine learning algorithm; and g) data output of the processed measurement data, wherein the measurement data is output according to its classification.

17. Use of a sensor (1) according to at least one of the preceding claims 1 to 13 with a measuring device according to claim 14 or 15 and a method according to claim 16 for particle detection and for classifying particles in a fluid (32), wherein the classification is carried out at least in terms of the number of particles, material of the particles, shape of the particles and size of the particles.

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