Ultrasonic transducer system and method for monitoring an ultrasonic transducer system

Abstract

An ultrasonic transducer system (1) is proposed, comprising at least one generator (2), at least one transducer element (3), at least one measuring unit (6) and at least one analyzing unit (8, 10), wherein the generator (2) and the transducer element (3) are connected to one another for energy-related purposes and the generator (2) is designed to provide electrical energy for the transducer element (3) and the transducer element (3) is designed to convert the electrical energy provided by means of the generator (2) into a mechanical oscillation, and wherein the measuring unit (5) and the analyzing unit (8, 10) are connected to one another for signalling purposes and the measuring unit (5) is intended to monitor the transducer element (3) for measuring purposes and to transmit measurement data to the analyzing unit (8, 10), and the analyzing unit (8, 10) is configured to evaluate the measurement data provided by the measuring unit (6).

Description

[0001] Ultrasonic transducer system and method for monitoring an ultrasonic transducer system

[0002] Description

[0003] The invention relates to an ultrasonic transducer system and a method for monitoring an ultrasonic transducer system.

[0004] Ultrasonic transducer systems are used in various industrial applications, such as cleaning or process technology, and typically comprise a generator and at least one or more transducer elements. The generator generates a high-frequency alternating electrical voltage, which is applied to the transducer element and converted into a mechanical oscillation.

[0005] Mechanical vibration can be used to generate sound waves in liquid or solid media, as well as suspensions or dispersions. A workpiece immersed in the medium can be cleaned by the action of the sound waves. It is also conceivable that a medium being processed can be excited, and the chemical or physical properties of the medium itself can be changed by the effect of the sound waves.

[0006] Regardless of the application, the operation of the ultrasonic transducer system is desired to be highly reliable. In particular, the generated mechanical vibration should be adjustable as needed and, for example, should not exhibit any undesirable deviations in vibration amplitudes and frequencies over the operating life of the ultrasonic transducer system.

[0007] One challenge is that ultrasonic transducer systems in different applications are exposed to different influences, the effects of which are often difficult or even impossible to predict. These influences can result, for example, from environmental conditions, user handling of the ultrasonic transducer system, or other operating conditions. Because many of these influences interact with each other and their effects on the ultrasonic transducer system are often complex and non-linear, reliably predicting their long-term effects on the ultrasonic transducer system is difficult. Even with careful design and material selection, there is often a risk of unexpected wear, performance degradation, or even more serious damage to the ultrasonic transducer system.

[0008] It is therefore an object of the invention to propose an ultrasonic transducer system with high operational reliability and a method for increasing operational reliability.

[0009] The object is achieved by means of an ultrasonic transducer system according to claim 1 and a method according to claim 14. Advantageous further developments are the subject matter of dependent claims.

[0010] The ultrasonic transducer system according to the invention comprises at least one generator, at least one transducer element, at least one measuring unit, and at least one analysis unit. The generator and the transducer element are interconnected for power purposes. The generator is designed to provide electrical energy to the transducer element. The transducer element serves to convert the electrical energy provided by the generator into a mechanical oscillation. The measuring unit and the analysis unit are interconnected for signal transmission. The measuring unit is provided to monitor the transducer element and to transmit measurement data to the analysis unit. The analysis unit is configured to evaluate the measurement data provided by the measuring unit.

[0011] It is an advantage of the invention that, by means of the measuring unit and the analysis unit, it is possible to monitor the ultrasonic transducer system at a failure-critical system component, namely the transducer element, and to detect at an early stage whether deviations in the operation of the ultrasonic transducer system have occurred or are to be expected.

[0012] Metrological monitoring of the transducer element makes it possible to identify potential problems or malfunctions in the transducer element before they can lead to more serious failures or malfunctions. This allows appropriate measures to be taken in a timely manner to prevent the occurrence and spread of damage to the transducer element and increase the reliability of the entire ultrasonic transducer system. The ability to detect deviations in the operation of the ultrasonic transducer system also allows for proactive maintenance and repair planning, leading to improved availability and efficiency of the ultrasonic transducer system. Ultimately, this contributes to increasing the safety and performance of the system in which the ultrasonic transducer system is used and minimizing potential downtime.

[0013] The invention is fundamentally not limited to the design of the measuring unit or the manner in which it is operatively connected to the transducer element in order to monitor it. Rather, the invention is based on the fact that the use of a measuring unit and the analysis unit connected to it for signal processing leads to significant advantages over conventional ultrasonic transducer systems.

[0014] It is within the scope of the invention for the measuring unit to be arranged in spatial proximity to the transducer element and to have a detection range in which the transducer element is arranged. In particular, the measuring unit and the transducer element can be structurally combined into a single unit, for example by means of a common housing and / or a mechanical connection between the measuring unit and the transducer element. It is also within the scope of the invention for the measuring unit to be arranged at a distance from the transducer element. This is conceivable, for example, if the measuring unit is designed to detect a measured variable that does not have to be measured directly at the transducer element. This includes, for example, an electrical characteristic of a high-frequency alternating voltage that is present at the transducer element but can be measured at the generator, or the high-frequency current that flows through the transducer element.

[0015] In particular, the measuring unit is designed to record the measured variable over an operating period of several days, weeks or months and / or at an adjustable sampling rate and to output it to the analysis unit. The sampling rate can be 1 Hz, for example, but can also be higher and can be selected depending on the measured variable to be recorded, for example to avoid undersampling of the measured variable to be recorded. Within the scope of the invention, the measuring unit can have one or more sensors by means of which at least one state or a change in state during operation of the transducer element can be measured. It is conceivable that the sensor is connected to at least one electrical control unit by means of which the sensor is controlled and supplied with energy. In particular, it is possible to determine a temporal progression of the measured variable by means of the ultrasonic transducer system.In particular, process monitoring of the system in which the ultrasonic transducer system is used is possible.

[0016] The ultrasonic transducer system preferably comprises a plurality of transducer elements that are mechanically and / or electrically coupled to one another. Mechanical coupling can be achieved, for example, by means of a common membrane or in a submersible transducer. Electrical coupling can be provided by connecting the plurality of transducer elements to a single generator. It is within the scope of the invention for a corresponding plurality of measuring units to be assigned to the plurality of transducer elements, wherein each transducer element can be monitored by means of the measuring unit assigned to it. Alternatively, it can be provided that a common measuring unit is provided for at least two transducer elements. It is also conceivable for several measuring units to be assigned to one transducer element, which serve to metrologically monitor the transducer element.

[0017] Within the scope of the invention, the analysis unit forms part of the ultrasonic transducer system and serves to process collected data or information so that conclusions can be drawn from the acquired measurement data regarding the state of the transducer element or its changes during operation. For example, it is possible to interpret complex data sets, recognize patterns, identify trends, or extract other relevant information.

[0018] In particular, the ultrasonic transducer system according to the invention is intended and suitable for use in an ultrasonic cleaning system or in an ultrasonic processing system. In an ultrasonic cleaning system, the transducer element can be immersed in a cleaning medium together with a workpiece to be cleaned. For the desired cleaning process, the transducer element generates ultrasonic waves, which lead to the formation of cavitation bubbles in the cleaning medium. These cavitation bubbles implode near the workpiece surface, thereby dissolving dirt particles and contaminants to be removed. In the ultrasonic cleaning system, several transducer elements can preferably be used, which are spatially distributed in such a way as to enable uniform sound propagation in the cleaning medium.Monitoring the ultrasonic transducer elements is advantageous because it ensures that none of the transducer elements has failed unnoticed or will fail in the future. In particular, monitoring the transducer elements can be used to determine a process characteristic of the ultrasonic cleaning system, particularly a cleaning parameter.

[0019] In an ultrasonic processing system, the transducer element can be immersed together with a fluid in the liquid medium to be processed. For the desired process, the transducer element generates ultrasonic waves, which lead to the formation of cavitation bubbles in the process medium. These cavitation bubbles implode in the medium, causing the desired mechanical effects, such as emulsification, dispersion, sonochemical reactions, or other chemical-physical effects beneficial to the process. Preferably, several transducer elements can be used in the ultrasonic processing system, spatially distributed to enable uniform sound propagation in the process medium. Monitoring the ultrasonic transducer elements is advantageous because it ensures that none of the transducer elements has failed unnoticed or will fail in the future.In particular, by monitoring the transducer elements, conclusions can be drawn about a process characteristic of the ultrasonic processing system, in particular about a process parameter.

[0020] Preferably, at least the measuring unit and the analysis unit can be retrofitted to an existing ultrasonic transducer system comprising a generator and a transducer element. In an advantageous development, the measuring unit comprises at least one electrical sensor, which is designed to detect an electrical measurement variable at the transducer element, in particular an electrical voltage and / or an electrical current and / or a characteristic variable dependent thereon.

[0021] In one conceivable embodiment, the electrical sensor is designed as a current sensor and is electrically connected to the converter element in the region of the electrical connections to measure the electrical current at the converter element. Additionally or alternatively, the current sensor can also be galvanically isolated from the electrical connections to measure the current without contact and based on the magnetic flux density generated by the electrical current. It is also conceivable for the electrical sensor to be designed as a voltmeter to measure the voltage applied to the converter element.

[0022] Since the transducer element of an ultrasonic transducer system, as mentioned above, is typically operated with a high-frequency alternating voltage, it is advantageous, particularly for the consideration of the Shannon-Nyquist sampling theorem, if the sampling rate at which the electrical sensor is operated is at least twice the highest frequency component of the measured variable. In other words, it is advantageous if the sampling frequency is at least twice the highest frequency of the alternating voltage signal. This is particularly useful if the electrical sensor is to be used to determine the phase position of an alternating voltage applied to the transducer element.

[0023] It is within the scope of the advantageous development that several electrical sensors are used to measure both the electrical voltage and the current applied to the converter element. This is particularly conceivable if these electrical measured variables are to be used to record a characteristic derived from the current and voltage, for example the power, reactive power or another variable dependent thereon. The analysis unit can further be configured to analyze the electrical measured variable or its temporal progression using an evaluation routine stored on the analysis unit. Preferably, the analysis unit is designed, using the evaluation routine stored thereon, to output a state or a change in state during operation of the converter element depending on the electrical measured variable.

[0024] In an advantageous further development, the measuring unit comprises at least one mechanical sensor which is intended to detect a mechanical measurement variable of the transducer element, in particular a position, a strain and / or an acceleration.

[0025] Investigations by the applicant have shown that undesirable deviations in the operation of a transducer element can be reliably detected not only by recording electrical measured variables, but also by recording mechanical measured variables from which the position, deformation or movement of the transducer element during its operation can be deduced.

[0026] Within the scope of the advantageous development, the mechanical sensor is not limited to a specific operating principle. Rather, the only relevant factor is that it is capable of detecting one of the aforementioned mechanical parameters. The mechanical sensor can be designed to detect the mechanical parameter in a contact-type manner, i.e. by means of mechanical contact with the transducer element, and / or in a contactless manner, i.e. without mechanical contact with the transducer element. It is further within the scope of the advantageous development that the mechanical measurement variable of the transducer element, in particular the position, the strain and / or the acceleration, are detected directly or indirectly. Indirect detection of the mechanical variables can occur, in particular, by converting a directly determined variable into the indirectly determined variable using a differential operation and / or an integral operation.It is therefore within the scope of the advantageous development that not only a position, speed, strain, or acceleration can be detected by means of the mechanical sensor, but also their respective changes. For example, the mechanical sensor can be a displacement sensor, by means of which a mechanical deflection of the transducer element can be directly detected. By performing the above-mentioned differential operation between two measured deflections, a strain and / or speed of the transducer element can be deduced. A further differential operation enables the determination of the acceleration of the transducer element. In particular, the mechanical deflection is not an absolute position of the transducer element, but a change in position between two states of the transducer element in question.

[0027] Additionally or alternatively, a speed sensor and / or an acceleration sensor can be provided, which is designed to detect a speed or acceleration of the transducer element. In particular, the sensor can be designed as a microelectromechanical system (MEMS). Additionally or alternatively, the mechanical sensor can comprise an array of strain gauges, by means of which a strain of the transducer element can be detected. It is also conceivable for the mechanical sensor to be designed as a laser vibrometer to determine a deflection speed of the transducer element.

[0028] In an advantageous further development, the measuring unit comprises an environmental sensor which is provided to detect an atmospheric measured variable in the environment of the transducer element, in particular an ambient temperature and / or an ambient humidity and / or an ambient pressure.

[0029] As the applicant's investigations have shown, the operating environment of an ultrasonic transducer system can have a significant impact on its operational reliability. Excessively high or low temperatures, as well as significant temperature fluctuations, can particularly affect the materials of the transducer element and lead to premature wear or failure. For example, high temperatures can reduce the elasticity of rubber or plastics on the transducer element seals, while low temperatures can lead to breakage or cracking. Humid environments can cause corrosion or oxidation, which can shorten the service life of the transducer elements. Corrosion can reduce the strength of metal components and lead to sudden failure. Atmospheric pressure can affect the functionality of the transducer element seals.

[0030] It is within the scope of the invention that the environmental sensor is designed such that a plurality of measuring transducers are combined to form a sensor module, by means of which the ambient temperature and / or the ambient humidity and / or the ambient pressure can be measured individually or jointly. In particular, such an environmental sensor can be designed as a microelectromechanical system (MEMS), by means of which at least one of the atmospheric measured variables can be determined. In particular, the environmental sensor can be arranged at a distance from the transducer element, but preferably in a common housing.

[0031] It is within the scope of the above-described embodiments that the ultrasonic transducer system comprises the electrical sensor, the mechanical sensor, and the environmental sensor in combination with one another, or perhaps only some of the aforementioned sensors. As explained in more detail below, it is particularly advantageous that the aforementioned sensors are suitable for providing measurement data that can be used to indirectly infer and even predict properties of the transducer element without having to be directly determined.

[0032] In an advantageous further development, the analysis unit is configured to detect and / or predict a state and / or change in state during operation of the converter element depending on the evaluated measurement data.

[0033] By analyzing the measurement data, the analysis unit can identify potential problems or deviations in the operation of the transducer element at an early stage, which is particularly possible with process monitoring. Process monitoring can be viewed as the continuous observation and analysis of the operation of the ultrasonic transducer system. Since the operation of the ultrasonic transducer system often has a direct influence on the process control of the application in which the ultrasonic transducer system is used, it can be used to ensure that the desired results are achieved with the said application and, in particular, that standards, specifications, or quality norms are adhered to. This can also avoid unnecessary downtime of the ultrasonic transducer system and improve operational efficiency. A further advantage is the possibility of early fault detection.The analysis unit enables the identification of deviations in the operation of the transducer element at an early stage. This allows potential malfunctions or defects to be detected before they develop into more serious problems. This helps avoid expensive repairs or unforeseen failures and extends the overall service life of the transducer element and the ultrasonic transducer system. Furthermore, the beneficial training opens up the possibility of preventive maintenance. Thanks to the analysis results, maintenance work can be planned and carried out before unplanned downtime occurs. This improves the availability of the transducer element and can reduce operating costs. A further advantage is that the analysis unit is also capable of predicting the behavior of the transducer element based on the measurement data.This capability makes it possible to proactively optimize operating parameters and better adapt the converter element to current requirements and load conditions.

[0034] The analysis unit can comprise one or more components. In particular, the analysis unit can be configured to preprocess the acquired measured variables and evaluate the preprocessed measured variables with regard to the operating state of the transducer element. For this purpose, the analysis unit can preferably comprise a preprocessing module and an evaluation module, which are interconnected via signal transmission.

[0035] Preprocessing of the measured variable, particularly by means of the preprocessing module, can be performed in various ways and may include, for example, analog-to-digital conversion, digital-to-analog conversion, filtering, calculation of differences, quotients, or averaging, a transformation, particularly a Fourier transformation, data compression, measured value smoothing or interpolation, or signal amplification. The preprocessing module can be embodied in the form of an electrical controller, particularly a microcontroller. A preprocessing module can be connected to one or more measuring units for signal processing purposes.

[0036] Analog-to-digital conversion (ADC) converts analog input signals into digital values. This allows the electrical control unit to process the data in digital form and store, analyze, or transmit it via digital interfaces.

[0037] Conversely, the microcontroller can also perform digital-to-analog conversion (DAC). This converts digital values ​​into analog signals, for example, to generate analog output signals.

[0038] Filtering can be used to reduce unwanted noise or isolate specific frequency ranges. Various digital filter types are available, such as low-pass, high-pass, band-pass, and notch filters.

[0039] By calculating the mean, the quotient or the difference, parameters that are easier to interpret can be calculated from the measured values.

[0040] The Fourier transform, specifically the fast Fourier transform (FFT), enables the electrical control unit to transform signals from the time domain to the frequency domain. This allows specific frequency components to be identified and spectral analysis to be performed.

[0041] In applications with limited memory, data compression can be used to reduce the amount of data available and to store and transfer information more efficiently.

[0042] Signal smoothing and interpolation are measures used to smooth irregular or noisy signal curves and to supplement missing data points. The measurement signals can be amplified to achieve optimal processing results. Further processing of the preprocessed measured variable, particularly by means of the evaluation module, can be carried out using a computing unit and an evaluation routine configured for it. The evaluation routine can be implemented based on a statistical method, machine learning, and / or artificial intelligence. This makes it possible to draw conclusions about the state of the transducer element depending on the measured variable, in particular whether it is in a nominal operating state or a faulty operating state, or whether such a state is imminent.In a simple embodiment, the analysis unit can be configured to compare the measured variable or the temporal progression of the measured variable with one or more previously defined limit values ​​and, depending thereon, to output a signal indicating whether the measured variable or its progression is within a tolerable range or not.

[0043] The above-mentioned statistical methods can, for example, comprise a regression analysis, by means of which a relationship between one or more independent measured variables, which are preferably provided by at least one of the sensors described above, and at least one dependent variable, in particular the state of the transducer element, can be modeled. Linear and / or non-linear regression models can be used to determine or predict a state and / or a change in state. It is also conceivable that a cluster analysis is used to group sufficiently similar data points of a measurement and thus identify states and / or changes in state by recognizing patterns within and between clusters. Furthermore, it is conceivable that a trend analysis is carried out in which a forecast of the further development of previously measured measured variables is made.

[0044] The machine learning methods also mentioned above can be used in addition to or as an alternative to the statistical methods described above and preferably include the use of an artificial neural network and / or a support vector machine. These make it possible to output a relationship between an electrical measurement variable and / or a mechanical measurement variable and / or an atmospheric measurement variable and a state and / or a change in state of the transducer element using a trained model. This is advantageous because no analytical modeling step is required.

[0045] When using the methods described above, it is conceivable to determine a state and / or state change of the transducer element, for example, depending on at least one experimental data set. Such a data set can be collected using one or more reference transducer elements, which are in particular identical in design to the monitored transducer element. Through experimental operation, these reference transducer elements can be excited to mechanical vibrations until a reference state and / or reference state change is reached, in particular a defect or defect propagation. During this time, the reference transducer element can be monitored using an electrical sensor and / or mechanical sensor and / or environmental sensor.For a subsequent determination of the condition and / or change in condition of the transducer element monitored during industrial operation, the measured variables recorded can be compared at least with the determined reference measured variables, in particular with a characteristic curve that indicates the measured variables as a function of the time until the occurrence of the defect. This can be used, for example, to determine a remaining service life, in particular until the occurrence of the defect, and thus predict a defect. Instead of an experimental approach, such a data set can also be obtained through simulation or analysis.

[0046] In an advantageous further development, the transducer element comprises at least one piezo element, in particular a piezo ceramic, and the analysis unit is configured to detect and / or predict a state of the piezo element.

[0047] Studies have shown that metrological monitoring of the transducer element makes it possible to determine specific information about the condition of the piezo element used within it. This is particularly advantageous because, in addition to the piezo element, the transducer element can also include electrodes, a damping layer, a protective layer, or a housing, all of which fundamentally influence the measured values. Surprisingly, however, it has been shown that metrological monitoring of the transducer element makes it possible to indirectly and specifically draw conclusions about the condition and / or a change in the condition of the piezo element.

[0048] Preferably, the analysis unit is configured to determine the state of the piezoelectric element indirectly and as a function of the electrical measurement variable and / or the atmospheric measurement variable and / or the mechanical measurement variable. In particular, the state of the piezoelectric element includes a mechanical prestress and / or damage and / or adhesion to at least one other component of the transducer element.

[0049] Studies have shown that simply determining an electrical parameter can provide information regarding one of the aforementioned properties of the piezo element. However, a mechanical and / or atmospheric parameter can also advantageously be taken into account in order to validate, in particular to verify or falsify, an estimate of a state or change in state that can be determined using an electrical parameter. This can be achieved, in particular, depending on one of the evaluation methods described above based on statistics, artificial intelligence, or machine learning. This makes it possible, for example, to interpret anomalies in a measured voltage curve caused by an ambient temperature accordingly and not mistakenly attribute them to a transducer defect.

[0050] It is therefore an advantage of the combined consideration of the electrical measurand and / or the atmospheric measurand and / or the mechanical measurand that the state and / or the change in state can be determined with a higher reliability than by a separate measurement and individual evaluation of said measurands.

[0051] Studies have shown that it is not absolutely necessary to determine a mechanical measurement variable to determine the mechanical condition of the transducer element. In an advantageous embodiment of the ultrasonic transducer system, the condition and / or change in condition of the transducer element can therefore be determined independently of a mechanical measurement variable, so that the use of a mechanical sensor can generally be dispensed with. However, it is within the scope of the advantageous development that a mechanical sensor can also be used to monitor the transducer element.

[0052] In particular, at least one characteristic variable can be determined as a function of the mechanical prestress and / or damage and / or adhesion, preferably a classification of the mechanical prestress and / or damage and / or adhesion of the piezo element.

[0053] Advantageously, the electrical and / or atmospheric and / or mechanical measured variables not only make it possible to qualitatively detect a condition and / or change in condition of the transducer element, but also, in particular, to identify its manifestation, which is preferably classifiable. In other words, the ultrasonic transducer system not only makes it possible to determine whether a transducer element is directly affected by an existing or impending defect, but also to determine the extent to which this defect has already occurred or, for example, the timeframe and / or extent over which it is imminent. This makes it possible, for example, to plan required maintenance measures and, in particular, to prioritize them when multiple transducer elements are being monitored. This is particularly advantageous for ultrasonic transducer systems with a large number of transducer elements.

[0054] It is also within the scope of the invention that no preprocessing of the measurement signal needs to be carried out in order for it to be evaluated or that the preprocessing and evaluation take place in a coherent evaluation routine in the analysis unit.

[0055] In an advantageous development, the ultrasonic transducer system comprises a plurality of transducer elements, each of which is connected to the generator for power supply purposes, as well as a plurality of measuring units, each of which is assigned to a transducer element and configured to monitor the respective transducer element. While it is sufficient for many applications to provide an ultrasonic transducer system with just one transducer element that generates the desired mechanical vibration, the geometry or dimensions of one or more bodies, which are to be cleaned or otherwise processed using ultrasound, may require the use of multiple transducer elements.When the converter elements are operating simultaneously, it is not always possible to determine whether and which of the converter elements is about to fail or has already experienced a malfunction. For this reason, it is advantageous to equip each converter element with one or more measuring units to monitor them.

[0056] In an advantageous development, the analysis unit, in particular the preprocessing module, is at least partially integrated into the measuring unit, in particular the sensor. For this purpose, the analysis unit, preferably a preprocessing module of the analysis unit, and the measuring unit, in particular a sensor of the measuring unit, can be integrated into a common system, in particular an embedded system. The preprocessing module can, as already indicated above, be designed as a microcontroller. In particular, the measuring unit and the preprocessing module can be integrated into a common housing, which can be arranged in the vicinity of the transducer element. The preprocessing module can have standardized interfaces by means of which evaluated measurement data can be output to the evaluation module.

[0057] In an advantageous development, the analysis unit, in particular the evaluation module, is at least partially integrated into the generator. In this case, the analysis unit, in particular the evaluation unit and the generator can be spatially bundled, in particular in a common housing, and preferably connected to one another in terms of signaling. Spatial bundling of the analysis unit and the generator is advantageous because the measuring unit can be arranged on the transducer element or in its vicinity in a space-saving manner and the evaluation of the acquired measurement data can take place spatially separate from the transducer element. The signaling connection between the analysis unit and the generator makes it possible to evaluate the measurement data acquired by the measuring unit and use it to control the generator.In particular, it is possible to control or regulate the operation of the converter element by means of the generator depending on the measured variables at the converter element.

[0058] In an advantageous development, the analysis unit, in particular the preprocessing module and / or the evaluation module, is at least partially integrated into an evaluation computer. Within the scope of the advantageous development, an evaluation computer can be designed as an industrial PC, by means of which the measuring unit is operated and by means of which the collected measurement data can be evaluated. One advantage of the evaluation computer is that it can also be provided for controlling a system, in particular an ultrasonic cleaning system and / or a processing system, in which the ultrasonic transducer system is used. Another advantage is that the measuring unit can be arranged in a space-saving manner on the transducer element or in its vicinity and the evaluation of the collected measurement data, as explained above, can take place spatially separate from the transducer element.

[0059] In an advantageous further development, at least the measuring unit and the analysis unit are connected to a bus system and are connected to each other via the bus system in terms of signal technology.

[0060] One advantage of connecting the measuring unit and the analysis unit to a bus system is that the bus system enables easy data transmission between the measuring unit and the analysis unit. The recorded measurement data can be transferred efficiently and quickly to the analysis unit, where it is further processed and analyzed to obtain relevant information. In addition, the effort required for signal cabling of the measuring device is significantly reduced, with a single data connection being used to provide the signal connection between the measuring unit and the analysis unit. Furthermore, the use of a bus system promotes the expandability of the ultrasonic transducer system with additional components, in particular with further measuring units and analysis units. This advantageous further development is not limited to a specific bus system.Rather, it is within the scope of the advantageous development that the bus system has one or more different types of bus subsystems. In particular, the bus system can be designed at least partially according to one of the following systems: Universal Serial Bus (USB), Controller Area Network (CAN), Ethernet, Profibus, Modbus, Integrated Circuit (I2C), Serial Peripheral Interface (SPI).

[0061] In an advantageous development, the bus system comprises a central control unit, in particular a programmable logic controller, which is signal-connected to the generator. Furthermore, it is advantageous if the central control unit is signal-connected to the evaluation unit. The central control unit can serve to control the generator. In particular, this can be done depending on the evaluated measurement signals. This allows a control loop to be formed with which the converter element is operated.

[0062] As mentioned above, the object is also achieved by means of a method according to claim 14.

[0063] The method according to the invention comprises the following process steps:

[0064] A) Providing an ultrasonic transducer system according to the invention or an advantageous development thereof;

[0065] B) Metrological monitoring of one or more transducer elements by means of the measuring unit and generation of measurement data;

[0066] C) transmitting the measurement data from the measuring unit to the analysis unit;

[0067] D) Evaluate the measurement data using the analysis unit.

[0068] Preferably, the method also comprises the following method step:

[0069] E) Detecting and / or predicting a change in the state of the transducer element depending on the evaluated measurement data.

[0070] In particular, in process step A), the ultrasonic surge transducer system or an advantageous development thereof is provided in an ultrasonic cleaning system or an ultrasonic processing system. In a process step F), a process parameter of the ultrasonic cleaning system or an ultrasonic processing system is determined based on the evaluated measurement data.

[0071] According to the development described above, it is thus indirectly possible to draw conclusions about one or more process parameters of an ultrasonic cleaning system or an ultrasonic processing system by monitoring the ultrasonic transducer system. In particular, the process parameter can indicate a state or a change in state of the respective system or of a workpiece or process medium being machined or treated therein. In particular, a quality parameter of the workpiece or medium depends on the process parameter. The quality parameter of the workpiece or medium is preferably determined as a function of the process parameter.

[0072] In particular, the method according to the invention or an advantageous development thereof is suitable for implementation with the ultrasonic transducer system according to the invention or an advantageous development thereof. In this respect, the statements regarding the technical features of the ultrasonic transducer system and the advantages achievable thereby apply accordingly.

[0073] Exemplary embodiments of the inventive objects are explained below with reference to the figures.

[0074] Figure 1 shows a first ultrasonic transducer system;

[0075] Figure 2 shows a second ultrasonic transducer system.

[0076] Figure 1 shows a first ultrasonic transducer system 1, which is designed as a component of an ultrasonic cleaning system in a manner not shown in detail here.

[0077] The ultrasonic transducer system 1 shown in Figure 1 comprises a generator 2 which is designed to generate an alternating voltage with a frequency in the range of, for example, 18 kHz to 1 MHz. The ultrasonic transducer system 1 also has a plurality of transducer elements 3, of which only one is provided with a reference numeral in Figure 1 for better clarity. The transducer elements 3 each comprise a piezoelectric component which deforms when an electrical voltage is applied, whereby the inverse piezoelectric effect is utilized. By applying the alternating voltage of the generator 2 via the electrical connection 4, the transducer elements 3 are excited to a mechanical oscillation. If the oscillation amplitude is sufficiently large, this oscillation leads to the formation of acoustic cavitation in a cleaning fluid.The gas or vapor bubbles generated thereby collapse, at least partially, abruptly on a surface to be cleaned and thereby release particles or filmy contaminants to be removed.

[0078] A challenge in the operation of ultrasonic transducer systems in ultrasonic cleaning systems or other industrial applications is that transducer elements 3 can be exposed to harsh environmental conditions. This creates disruptive influences on the transducer elements 1, which, particularly during long operating times, can lead to undesirable deviations in the generated mechanical vibrations or failures of the entire ultrasonic transducer system 1. This manifests itself, for example, in a lack of consistency regarding the amplitude or frequency of the generated mechanical vibration.

[0079] To detect an undesirable deviation in the operation of the vibration elements 3, the ultrasonic transducer system 1 shown in Figure 1 comprises a plurality of measuring units 5, each of the transducer elements 3 being assigned a measuring unit 5 that monitors the transducer element 3 assigned to it. For clarity, only one of the measuring units 5 is provided with a reference symbol. The measuring units 5 are designed as measuring boxes (not shown in detail), each of which is connected upstream of the electrical connections of the transducer elements 3.

[0080] The measuring units 5 each comprise a sensor 6. In the exemplary embodiment shown in Figure 1, each sensor is an electrical sensor for monitoring an electrical voltage applied to the electrical connections of the transducer elements 3. Alternatively or additionally, the sensor can also be designed as a mechanical sensor, by means of which a mechanical measurement variable can be detected, such as a relative deflection of the transducer as well as a strain or acceleration. It is also conceivable for the sensors 6 to each comprise an environmental sensor and serve to detect an atmospheric measurement variable in the vicinity of the transducer elements 3, for example an ambient temperature, air humidity, or air pressure.

[0081] Using sensors 6, it is possible to ensure continuous monitoring of the converter elements 3, whereby the sensors 6 can be operated continuously for monitoring periods ranging from days to weeks. The sampling rates can generally vary and depend on the measured variable to be recorded. In the embodiment shown in Figure 1, the sampling rate is twice the frequency of the voltage applied to the terminals of the converter elements 3.

[0082] The sensors 6 are signal-connected to a common preprocessing module 8 in the form of a microcontroller via a common bus connection 7. The measured variables acquired by the sensors 6 are transmitted via the bus connection to the preprocessing module 8, where they are preprocessed. In this case, the preprocessing includes filtering the detected electrical voltage.

[0083] The preprocessing module 8 is connected to an evaluation module 10 via a further bus connection 9, by means of which the preprocessed data is analyzed in order to detect any anomalies in the operation of the converter elements 3. The preprocessing module 8 and the evaluation module 10 can be considered together as an analysis unit.

[0084] Using the evaluation module 10, it is possible to detect faults or undesirable deviations in the operation of the converter elements 3 that have already occurred or are about to occur. Deviations that have already occurred can be detected by comparing the data entered into the analysis unit with limit values ​​previously stored on the evaluation module 10. Impending deviations can be determined using the evaluation module 10 by analyzing statistical parameters and trends in the temporal course of the measured variables. It is also within the scope of the embodiment shown here that a method based on artificial intelligence is implemented on the evaluation module 10, by means of which deviations that have already occurred and / or are about to occur can be detected or predicted in the operation of the converter elements 3.

[0085] In a manner not shown in detail here, the transducer element 3 comprises at least one ceramic piezo element and the preprocessing module 8 and / or the evaluation module 10 is configured to detect a state of the piezo ceramic and, if necessary, to predict it.

[0086] Studies have shown that by monitoring the transducer element using metrological techniques, it is possible to determine specific information about the condition of the piezoelectric element installed within it. This is particularly surprising because, in addition to the piezoelectric element, the transducer element can also comprise electrodes, a damping layer, a protective layer, or a housing, all of which fundamentally influence the measured variables, which are measured in particular by means of an electrical sensor, a mechanical sensor, or an environmental sensor. Surprisingly, however, it has been shown that the detection of at least one of the aforementioned measured variables makes it possible to indirectly infer the condition or a change in the condition of the piezoelectric element.

[0087] The preprocessing module 8 and / or evaluation module 10 are further configured to determine and predict the state of the piezo element indirectly and as a function of the electrical measurement variable and / or the atmospheric measurement variable and / or the mechanical measurement variable. In particular, the state of the piezo element can be a mechanical prestress and / or damage and / or adhesion to at least one other component of the transducer element. This is surprising in that it is already possible to determine information regarding one of the aforementioned properties of the piezo element by determining an electrical parameter. However, a mechanical and / or atmospheric measurement variable can also advantageously be taken into account to determine the aforementioned properties.For example, a mechanical and / or atmospheric measurement can be taken into account to validate, in particular, verify, or falsify an estimate of a state or change in state that can be determined from an electrical measurement. This can be dependent on one of the evaluation methods described above based on statistics, artificial intelligence, or machine learning. This makes it possible, for example, to interpret anomalies in a measured voltage curve caused by an ambient temperature accordingly and not directly attribute them to an existing or impending converter defect.

[0088] In addition, at least one parameter can be determined as a function of the mechanical preload and / or damage and / or adhesion, whereby in particular a classification of the mechanical preload and / or damage and / or adhesion of the piezo element can be carried out. It is therefore not only possible to qualitatively detect a condition and / or change in condition, but in particular also a manifestation of this, which can be classified. In other words, using the ultrasonic transducer system, it is not only possible to obtain information about whether a transducer element is directly affected by an existing or impending defect, but also to what extent this defect has already occurred or in what time frame it is imminent. This makes it possible to plan necessary maintenance measures and, in the case of multiple monitored transducer elements, to prioritize them.

[0089] In a manner not shown in detail here, the evaluation module 10 can be integrated into the generator 2 and connected to it for signal processing. This makes it possible to operate the generator 2 depending on the evaluated measured variables and thus also to control the operation of the converter elements 3. It is also possible for the preprocessing module 8 and the evaluation module 10 to be integrated into a common functional unit and form the analysis unit.

[0090] Figure 2 shows another ultrasonic transducer system 1 which, in accordance with the explanations for Figure 1, comprises a generator 2 which is energetically connected to a plurality of transducer elements 3 and excites them to mechanical oscillation by means of a high-frequency alternating voltage. As also already explained with reference to Figure 1, a plurality of measuring units 5 are provided, by means of which the transducer elements 3 are individually monitored and the measurement data acquired by the sensors 6 are input into the pre-processing module 8 via a bus connection 7. In contrast to the embodiment shown in Figure 1, the pre-processing module 8 is not connected directly to the evaluation module 10 via the bus connection 9, but rather to the generator 2, which in turn is connected via the bus connection 11 to an evaluation computer 12 in which the evaluation module 10 is integrated.In other words, the measuring units 5, the generator 2, and the evaluation module 10 are arranged in a common bus system, through which they communicate with each other via signals. The evaluation computer 12 is connected to a central control unit 14 via the bus connection 13. This unit serves to control the generator 2 via the bus connection 15.

Claims

Claims 1. Ultrasonic transducer system (1) with at least one generator (2), at least one transducer element (3), at least one measuring unit (5) and at least one analysis unit (8, 10), wherein the generator (2) and the transducer element (3) are connected to one another in terms of energy, the generator (2) is designed to provide electrical energy for the transducer element (3), and the transducer element (3) is designed to convert the electrical energy provided by the generator (2) into a mechanical oscillation, the measuring unit (5) and the analysis unit (8, 10) are connected to one another in terms of signaling, the measuring unit (5) is provided to monitor the transducer element (3) in terms of measurement and to transmit measurement data to the analysis unit (8, 10), and the analysis unit (8, 10) is designed to evaluate the measurement data provided by the measuring unit (5).

2. Ultrasonic transducer system (1) according to claim 1, with a plurality of transducer elements which are mechanically and / or electrically coupled to one another and with a plurality of measuring units which are designed to monitor the transducer elements metrologically.

3. Ultrasonic transducer system (1) according to claim 1 or 2, wherein the measuring unit (5) comprises at least one electrical sensor (5) which is provided to detect an electrical measurement variable at the transducer element (3), in particular an electrical voltage and / or an electrical current and / or a characteristic variable dependent thereon and / or wherein the measuring unit (5) comprises at least one mechanical sensor (5) which is provided to detect a mechanical measurement variable of the transducer element, in particular a deflection and / or a strain and / or an acceleration and / or wherein the measuring unit (5) comprises at least one environmental sensor (6) which is provided to detect an atmospheric measurement variable in the environment of the transducer element, in particular an ambient temperature and / or an ambient humidity and / or an ambient pressure.

4. Ultrasonic transducer system (1) according to one of the preceding claims, wherein the measuring unit (5) is integrated into the transducer element (6).

5. Ultrasonic transducer system (1) according to one of the preceding claims, wherein the analysis unit (8, 10) is configured to detect and / or predict a state and / or change in state of the transducer element (3) as a function of the evaluated measurement data.

6. Ultrasonic transducer system (1) according to claim 5, wherein the transducer element (3) comprises at least one piezo element, in particular a piezo ceramic, and the analysis unit (8, 10) is configured to detect and / or predict a state and / or change in state of the piezo ceramic.

7. Ultrasonic transducer system (1) according to claims 3 and 6, in which the analysis unit (8, 10) is configured to determine the state and / or change in state of the piezo element indirectly and as a function of the electrical measurement variable and / or the atmospheric measurement variable and / or mechanical measurement variable, preferably in that the state and / or the change in state can be estimated as a function of the electrical measurement variable and validated as a function of the atmospheric and / or mechanical measurement variable.

8. Ultrasonic transducer system (1) according to claim 7, wherein the state and / or change in state relates to a mechanical prestress and / or damage and / or adhesion of the piezo element to at least one other component of the transducer element (3), in particular at least one parameter depending on the mechanical prestress and / or damage and / or adhesion, preferably a classification of the mechanical prestress and / or damage and / or adhesion of the piezo element.

9. Ultrasonic transducer system (1) according to one of the preceding claims, with a plurality of transducer elements (3), which are each connected to the generator (3) for energy purposes and with a plurality of measuring units (5), wherein each of the measuring units (5) is at least partially assigned to one of the transducer elements and is designed to monitor the respective transducer element by measurement.

10. Ultrasonic transducer system (1) according to one of the preceding claims, in which the analysis unit has a preprocessing module (8) and an evaluation module (10) which are connected to one another by signal technology.

11. Ultrasonic transducer system (1) according to one of the preceding claims, in which the analysis unit (8, 10) is at least partially integrated into the measuring unit (5), wherein in particular the preprocessing module (8) is integrated into the measuring unit (5).

12. Ultrasonic transducer system (1) according to one of the preceding claims, in which the analysis unit (8, 10) is at least partially integrated into the generator (2), wherein in particular the evaluation module (10) is integrated into the generator (2).

13. Ultrasonic transducer system (1) according to one of the preceding claims, in which the analysis unit (8, 10) is at least partially integrated into an evaluation computer (12).

14. Method for monitoring an ultrasonic transducer system (1) with the following method steps: A) providing an ultrasonic transducer system (1) according to one of claims 1 to 13; B) Metrological monitoring of the transducer element (3) by means of the measuring unit (5) and generation of measurement data; C) transmission of the measurement data from the measuring unit (5) to the analysis unit (8, 10); D) Evaluation of measurement data using the analysis unit (8, 10).

15. Method according to claim 14 with method step E) Detecting and / or predicting a change in the state of the transducer element (3) depending on the evaluated measurement data.

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