DE102019209353B4 - Diaphragm seal system with monitoring function - Google Patents

Abstract

Pressure transmitter system (10) for determining a pressure of a medium, the pressure transmitter system (10) having:a pressure measuring cell (12) for outputting a pressure signal which is proportional to a pressure present at the pressure measuring cell (12);a pressure transmitter (20) with a hydraulic channel (22) and a process diaphragm (28), the hydraulic channel (22) extending between the pressure measuring cell (12) and the process diaphragm (28) and being designed to store a filling medium (24), so that a pressure on the process diaphragm ( 28) the effective process pressure of the medium can be transmitted at least partially to the pressure measuring cell (12) via the filling medium (24); at least one oscillating element (30) which is coupled to the process diaphragm (28) and which is designed to move the process diaphragm (28) to stimulate at least one vibration, to detect a decay behavior of the at least one vibration of the process membrane (28) and to generate a decay signal correlating with the decay behavior; anda control unit (16) which is coupled to the oscillating element (30) and which is set up to determine a change in the pressure transmitter system (10) based on the decay signal.

Description

field of invention

The invention generally relates to the field of sensor technology, in particular in process automation and/or the process industry. In particular, the invention relates to a pressure transmitter system for determining a pressure of a medium with an integrated monitoring function, for example for monitoring and/or checking the functionality of the pressure transmitter system. Furthermore, the invention relates to a method for determining a change in such a pressure transmitter system.

Technological background

To determine the pressure of a medium, for example a medium in a container, diaphragm seal systems are often used, which usually have a pressure transducer and/or a pressure measuring cell that is mechanically decoupled from the actual process and/or from the medium to be measured. For this purpose, diaphragm seal systems have a process diaphragm, one side of which can face the medium. The process diaphragm can also be hydraulically coupled to the pressure measuring cell, so that a process pressure exerted by the medium on the process diaphragm can be at least partially transmitted hydraulically to the pressure measuring cell. Based on the pressure present at the pressure measuring cell, a pressure signal and/or a measurement signal can be generated and/or output which is proportional to the pressure present at the pressure measuring cell and/or proportional to the process pressure present at the process diaphragm, i.e. the pressure of the medium can. A fill level of the medium in the container can also be determined based on the pressure signal and/or the measurement signal.

Diaphragm seal systems are used in process measurement technology, for example for pressure measurements on chemically aggressive media, which can attack the materials of conventional pressure sensors. A high level of chemical resistance can be provided in diaphragm seal systems by using alloyed stainless steel, for example for the process diaphragm. Diaphragm seal systems are also used at high temperatures of the medium to be measured, as these can have increased temperature resistance, since the pressure measuring cell is not directly exposed to the temperatures of the medium.

DE 10 2005 055 285 A1 describes a pressure transmitter. The pressure transmitter includes a pressure measuring cell for outputting a pressure-dependent signal, an electronic circuit for processing the pressure-dependent signal, and a diaphragm seal with a flexible separating membrane. The separating membrane closes a hydraulic path filled with a transmission medium in a pressure-tight manner. The hydraulic path extends from the separating membrane to the pressure measuring cell in order to transmit the pressure present at the separating membrane to the pressure measuring cell. The pressure transducer also has a hydraulic exciter, which communicates with the hydraulic path and is suitable for impressing pressure fluctuations on the hydraulic path, and an exciter circuit for driving the hydraulic exciter.

DE 10 2007 016 792 A1 discloses a measuring cell, in particular for pressure sensors, for the metrological detection of at least one physical variable of a medium adjacent to the measuring cell, with an elastic membrane. One side of the membrane is at least partially in contact with the medium and the other side of the membrane faces away from the medium. The membrane can be mechanically deflected via an activatable deflection means. At least one mechanical impulse can be transmitted from the membrane to the medium when the deflection means is activated.

DE 10 2007 046 016 A1 discloses a gas pressure sensor for a motor vehicle with at least one membrane for gas pressure measurement. The gas pressure sensor has a test circuit that causes the at least one membrane to deflect by means of at least one magnetic field and evaluates a measurement signal as a result of this deflection. The test circuit emits a signal as a function of the evaluation, this signal indicating that the at least one membrane is functional.

Summary of the Invention

With embodiments of the invention, an improved pressure transmitter system for determining a pressure, a fill level and/or a limit level of a medium in a container can be provided in an advantageous manner. The pressure of the medium is also referred to below as the process pressure.

This is made possible in particular by the subject matter of the independent patent claims. Further developments of the invention result from the dependent claims and the following description.

One aspect of the present disclosure relates to a diaphragm seal system for determining a Pressure, a process pressure, a fill level and/or a limit level of a medium. The medium can be liquid, gaseous, fluid and/or a solid. For example, the medium can be stored in a container, a container, a line, a pipeline and/or any other container. The pressure transmitter system has a pressure measuring cell, also called a pressure transducer, for outputting a pressure signal which is proportional to a pressure present at the pressure measuring cell. The pressure measuring cell can have, for example, a ceramic or a metallic membrane, via the deflection of which the applied pressure can be determined. Furthermore, the diaphragm seal system has a diaphragm seal with a hydraulic channel and a process diaphragm, with the hydraulic channel extending between the pressure measuring cell and the process diaphragm and being designed to store a filling medium, so that a process pressure of the medium acting on the process diaphragm is at least partially distributed via the filling medium can be transferred to the pressure measuring cell. The filling medium can be subjected to pressure and/or form. Furthermore, the pressure transmitter system has at least one oscillating element, which is coupled to the process diaphragm and which is designed to excite the process diaphragm to vibrate at least, to detect a decay behavior of the at least one vibration of the process diaphragm and to generate a decay signal that correlates with the decay behavior. Furthermore, the pressure transmitter system has a control unit which is coupled to the oscillating element and which is set up to change (and/or change) the pressure transmitter system and/or change (and/or change) at least one property of the pressure transmitter system based on the decay signal to be determined, for example based on processing and/or processing of the decay signal.

By exciting the process membrane to the at least one vibration and by determining the decay behavior of the vibration, a change in the pressure transmitter system can be determined in an advantageous manner. The change can in particular be a structural change, a mechanical change, a change in status and/or a functional change of one or more components of the pressure transmitter system. In the context of the present disclosure, the change in the pressure transmitter system can denote a change and/or modification of at least one structural, mechanical and/or functional property of the pressure transmitter system and/or at least one component of the pressure transmitter system. Thus, the components of the pressure transmitter system, in particular the pressure measuring cell, the process diaphragm and/or the pressure transmitter, can be checked and/or monitored with regard to their functionality. This can be done while the diaphragm seal system is in operation. In this way, an early detection of potential faults in the pressure transmitter system can also be made possible. In this way, the diaphragm seal system can be serviced, replaced and/or repaired in good time, for example before a malfunction or interruption of the process, such as a total failure of the diaphragm seal system, actually occurs.

The diaphragm seal can be designed in such a way that the pressure measuring cell is mechanically decoupled from the process and/or the process diaphragm. The hydraulic channel of the pressure transmitter can be formed, for example, in an internal volume of the pressure transmitter. The inner volume can be closed and/or pressure-tight. For example, the internal volume can be defined and/or limited by the process membrane, the hydraulic channel and the pressure measuring cell. The process membrane can close the hydraulic channel in a pressure-tight manner on one side, so that one side of the process membrane can face the hydraulic channel and an opposite side of the process membrane can face the medium. The pressure measuring cell can thus be in fluid communication with the process diaphragm via the hydraulic channel and/or the pressure measuring cell can be hydraulically coupled to the process diaphragm.

In the context of the present disclosure, the oscillating element can generally refer to a vibration generator and/or a vibration receiver. In general, the oscillating element can be set up to excite the process membrane to at least one oscillation, in particular mechanically to excite the oscillation, based on an electrical signal, for example a signal and/or control signal from the control unit. For example, the at least one oscillating element can be a piezoelectric oscillating element, an inductive oscillating element and/or a capacitive oscillating element.

The control unit can activate the oscillating element with an electrical signal, for example a control signal, and the oscillating element can excite the process membrane (eg mechanically) to the at least one oscillation based on the electrical signal, in particular in a targeted manner. In this case, the oscillating element can work as a transmitter. The at least one vibration can be caused by an excitation, in particular a mechanical and/or targeted excitation, of the process diaphragm with one or more excitation frequencies and one or more excitation amplitudes during one or more excitation periods. In other words, the control unit can be set up to Excite the process membrane via the oscillating element in a pulsed manner with at least one excitation frequency, at least one excitation amplitude and/or at least one excitation time period to produce the at least one oscillation. For example, the control unit can send a pulse packet as an electrical signal to the oscillating element in order to excite the process membrane in accordance with the pulse packet.

After excitation of the process diaphragm, the oscillating element can also determine the mechanical vibration of the process diaphragm during the decay of the vibration, detect the decay behavior of the vibration of the process diaphragm and convert and/or convert it into the decay signal, which can be evaluated by the control unit. In this case, the oscillating element can work as a receiver. The decay behavior of the at least one vibration of the process diaphragm can generally indicate a decay of the vibration over time. The decay behavior can, for example, be a decrease and/or change in at least one amplitude (or decay amplitude) of the vibration over time, at least one decay frequency over time, at least one change in the decay frequency over time, a frequency composition of the vibration during the decay and/or at least one decay period (e.g. for at least one decay frequency). Such and other quantities and/or information characterizing or describing the decay behavior can be encoded and/or contained in the decay signal.

The invention can be viewed as being based in particular on the findings explained below. In general, diaphragm seal systems are often used in harsh environments. Among other things, diaphragm seal systems can be used with chemically reactive and/or aggressive media. Diaphragm seal systems are also often used at high process temperatures of the medium to be measured. In the operation of diaphragm seal systems, wear and/or removal of material from the process diaphragm may occur due to chemical reactions and/or mechanical effects. The process diaphragm can also be deformed and/or destroyed by mechanical force, for example by pressure surges, steam surges and/or particles in the medium. A loss of filling medium in the diaphragm seal can also occur. In addition, at high temperatures, gas and/or air bubbles can form in the diaphragm seal system and thus the pressure of the filling medium in the diaphragm seal can change. Since diaphragm seal systems are often used to measure pressures in the range of a few mbar absolute pressure at temperatures of up to around 400°C or more, a change in the pressure of the filling medium can affect the measurement of the process pressure of the medium. If the pressure or initial pressure of the filling medium in the diaphragm seal falls, the boiling point of the filling medium can drop. This in turn can mean that the diaphragm seal system can only be used in a limited temperature range. If this temperature range is exceeded, the filling medium begins to outgas gases that are bound in the filling medium, and the filling medium begins to boil. The outgassing of the gases in the filling medium leads to a change in the pressure of the filling medium in the diaphragm seal. Overall, such a change in the pressure of the filling medium can lead to a drift of the pressure transmitter system in the zero point and/or in the rest position of the pressure transmitter system. With conventional diaphragm seal systems, this drift cannot be recognized by the diaphragm seal system and thus by the user. This may require the pressure measuring cell and/or the diaphragm seal system to be calibrated at regular intervals. A total failure of the diaphragm seal system and/or an escape of filling medium can also occur.

The pressure transmitter system according to the invention with the at least one oscillating element, on the other hand, advantageously allows such changes in the pressure transmitter system to be determined. In particular, early detection of the change in the pressure transmitter system and/or early detection of a potential fault can be made possible. This in turn allows countermeasures to be taken in good time. Regular calibration of the pressure transmitter system according to the invention can also advantageously be omitted and/or the frequency of the calibration can be reduced.

According to one embodiment, the at least one oscillating element is set up to excite the process diaphragm directly and/or immediately with (or to) the at least one oscillation. The oscillating element can, for example, be coupled to the process diaphragm in such a way that it can excite the process diaphragm directly and/or immediately to produce at least one vibration and/or impart the at least one vibration to the process diaphragm. In other words, the oscillating element can be designed not to excite the process diaphragm to the at least one oscillation indirectly via the filling medium of the hydraulic channel.

According to one embodiment, the at least one oscillating element is mechanically coupled to the process diaphragm. For example, the at least one oscillating element can be arranged and/or fastened on a side of the process diaphragm facing the hydraulic channel. The oscillating element can thus be arranged at least partially in the hydraulic channel of the pressure transmitter and/or in the pressure transmitter. For example, the oscillating element can be glued and/or welded to the process diaphragm.

According to one embodiment, the control unit is set up to determine the change in the pressure transmitter system relative to a reference state of the pressure transmitter system. For example, one or more reference values, for example for one or more parameters of the pressure transmitter system, can be stored in a memory of the pressure transmitter system, with the reference values being able to define the reference state of the pressure transmitter system.

According to one embodiment, the control unit is set up to determine the change in the pressure transmitter system based on a determination of at least one parameter of the pressure transmitter system. In the context of the present disclosure, determining a parameter can refer to determining a parameter of the parameter.

The control unit can be set up, for example, to derive and/or determine the at least one parameter (or the parameter of the parameter) from the decay signal. Alternatively or additionally, the control unit is set up to determine the change in the pressure transmitter system based on a determination of a change in at least one parameter (or at least one parameter of the at least one parameter) of the pressure transmitter system relative to at least one reference value of the at least one parameter, with the at least a reference value of the at least one parameter can be stored in a memory of the pressure transmitter system, for example. A change in the diaphragm seal system can be reflected in a change and/or change in one or more parameters of the diaphragm seal system. Wear and/or removal of material from the process diaphragm can, for example, change one or more parameters of the process diaphragm, such as a rigidity and/or a thickness of the process diaphragm. The change in the at least one parameter can also influence the decay behavior of the vibration, so that the change in the pressure transmitter system can be reliably determined by determining at least one parameter based on the decay behavior.

According to one embodiment, the at least one parameter comprises at least part of a decay curve of the vibration, at least one decay frequency of the vibration, at least one decay amplitude of the vibration, at least one resonant frequency of the process diaphragm, a thickness of the process diaphragm, a stiffness of the process diaphragm, an elasticity of the process diaphragm, a Deformation of the process diaphragm, a degree of deformation of the process diaphragm, a quality of the filling medium, a property of the filling medium and/or a filling pressure of the filling medium. The decay curve can describe a decay of the vibration of the process membrane over time, an amplitude curve of the vibration over time and/or a frequency curve of the vibration over time. By evaluating the decay signal, the control unit can thus determine one or more of the aforementioned parameters and thus enable comprehensive monitoring of the pressure transmitter system and/or monitoring of the functionality of the pressure transmitter system.

According to one embodiment, the control unit is set up to determine at least one excitation amplitude and/or at least one excitation frequency with which the process membrane can and/or can be excited. This can also allow conclusions to be drawn about a change in the diaphragm seal system, for example a change in the resonant frequency of the process diaphragm and/or a change in the pressure of the filling medium.

According to one specific embodiment, the control unit is also set up to output a warning signal in response to a determined change in the pressure transmitter system. In this case, the warning signal can be output as an electrical signal to a receiver. Alternatively or additionally, the warning signal can be output as an optical signal, for example on a display element of the pressure transmitter system, and/or as an acoustic signal, for example via a loudspeaker in the pressure transmitter system. A user of the diaphragm seal system can thus be informed of the detected change in the diaphragm seal system. The pressure transmitter system can also output additional information for this purpose, for example at least one determined parameter, one determined characteristic value of a parameter and/or a determined change in a parameter of the pressure transmitter system.

According to one embodiment, the control unit is also set up to carry out a calibration of the pressure transmitter system in response to a determined change in the pressure transmitter system. In other words, the pressure transmitter system can be set up to automatically carry out a calibration based on the determined change. For example, a zero point of the system can be established during calibration, for example to counteract a drift in the system. This can ensure that the diaphragm seal system is always reliable and accurate provides pressure readings. Overall, a measurement accuracy can be increased in this way.

According to one embodiment, the pressure transmitter system has a number of oscillating elements which are designed to detect the decay behavior of the at least one vibration at different positions of the process diaphragm and to generate a decay signal correlating with the decay behavior. For example, at least one oscillating element can be arranged centrally on the process diaphragm and at least one further oscillating element can be arranged on an edge area of the process diaphragm. A plurality of oscillating elements can also be arranged at a certain distance from a central axis and/or a center of the process diaphragm. In principle, however, any number of oscillating elements can be used. By using several oscillating elements, among other things, an expansion behavior and/or a stretching behavior of the process diaphragm, for example in one or more spatial directions, can be examined.

The control unit can, for example, control one or more of the oscillating elements in order to generate the at least one oscillation. If several oscillating elements are activated, they can be excited with pulse packets and/or electrical signals that are identical or different from one another. Several oscillating elements can be excited at the same time or at different times. The control unit can also evaluate one or more decay signals from one or more oscillating elements in order to determine the change in the pressure transmitter system. For example, the decay signals of different oscillating elements can be compared with one another.

• - Anregen, mit einem Schwingelement, einer Prozessmembran des Druckmittlersystems zu wenigstens einer Schwingung;
• - Detektieren, mit dem Schwingelement, eines Abklingverhaltens der wenigstens Schwingung der Prozessmembran, etwa nach Anregung und/oder nach gezielter Anregung;
• - Generieren eines mit dem Abklingverhalten korrelierenden Abklingsignals; und
• - Ermitteln einer Veränderung des Druckmittlersystems basierend auf einem Auswerten des Abklingsignals mit einer Steuereinheit des Druckmittlersystems.

A further aspect relates to a method for determining a change in a pressure transmitter system, as described above and below. The procedure has the following steps:

• - Excite, with an oscillating element, a process diaphragm of the pressure transmitter system to at least one oscillation;
• - Detecting, with the oscillating element, a decay behavior of the at least oscillation of the process diaphragm, for example after excitation and/or after targeted excitation;
• - generating a decay signal correlating with the decay behavior; and
• - Determining a change in the pressure transmitter system based on an evaluation of the decay signal with a control unit of the pressure transmitter system.

Features, elements and/or functions of the pressure transmitter system, as described above and below, can be features, elements and/or steps of the method, as described above and below, and vice versa.

A further aspect relates to a program element which, when executed on a control unit of a pressure transmitter system and/or a processor of the control unit, causes the pressure transmitter system to carry out steps of the method as described above and below. The program element can be stored, for example, in a memory of the pressure transmitter system and/or can include corresponding software instructions.

A further aspect relates to a computer-readable medium on which a program element is stored which, when executed on a control unit of a pressure transmitter system and/or a processor of the control unit, causes the pressure transmitter system to carry out steps of the method as described above and below.

Exemplary embodiments of the invention are described below with reference to the figures.

character list

• 1 shows a sectional view of a diaphragm seal system according to an embodiment.
• 2 shows a sectional view of a pressure transmitter system according to a further embodiment.
• 3 shows a flowchart to illustrate steps of a method for determining a change in a pressure transmitter system according to an embodiment.

Similar, similarly acting, identical or identically acting elements are provided with similar or identical reference symbols in the figures. The figures are merely schematic and not drawn to scale.

Detailed description of exemplary embodiments

1 shows a sectional view of a pressure transmitter system 10 according to an embodiment.

The pressure transmitter system 10 has a pressure measuring cell 12 with a pressure transmission element 14 , such as a membrane 14 . The pressure measuring cell 12 can, for example, be a ceramic pressure measuring device cell with a ceramic membrane 14 or a metal pressure measuring cell with a metal membrane 14. The pressure measuring cell 12 is set up to output a pressure signal that correlates with a pressure present on the outside of the membrane 14 . For this purpose, the pressure measuring cell 12 can have suitable electronics 16 and/or control unit 16 or be coupled thereto, which can convert the pressure signal into an (electrical) measurement signal, for example. The measurement signal can be transmitted via an electrical line 17 of the pressure transmitter system 10 and/or transmitted to a higher-level unit, for example. The pressure transmitter system 10 can also be supplied with power via the line 17 .

Furthermore, the diaphragm seal system 10 has a diaphragm seal 20 (e.g. with a base body) and a process diaphragm 28 . The process membrane 28 is hydraulically coupled to the pressure measuring cell 12 and/or the membrane 14 of the pressure measuring cell 12 . This allows the process membrane 28 to be mechanically decoupled from the pressure measuring cell 12. The process membrane 28 can, for example, be disc-shaped, for example made of plastic or metal. The process diaphragm 28 can also be bent and/or curved, for example sinusoidal, at least in a partial area.

The process membrane 28 is arranged on a process connection 26 . The pressure transmitter system 10 can be mounted on a container via the process connection 26 in such a way that one side of the process diaphragm 28 faces a medium in the container and/or is in physical contact with the medium. The process diaphragm 28 is at least partially elastically deformable, with a deformation and/or deflection of the process diaphragm 28 being representative of the process pressure of the medium acting on the process diaphragm 28 .

The pressure transmitter 20 also has a hydraulic channel 22 which is filled with a filling medium 24 . In this case, the filling medium 24 can be subjected to a pressure and/or an admission pressure. The filling medium 24 can be, for example, an oil, a hydraulic medium, a high-temperature oil and/or a medicinal white oil. The hydraulic channel 22 extends from the pressure measuring cell 12 to one side of the process diaphragm 28 so that the pressure measuring cell 12 is in fluid communication with the process diaphragm 28 via the hydraulic channel 22 . A process pressure exerted by the medium on the process diaphragm 28 can be at least partially transmitted to the pressure measuring cell 12 via the filling medium 24 . The pressure signal determined in this way and/or the measurement signal is therefore proportional to the process pressure present at the process diaphragm 28 . Based on the pressure signal of the pressure measuring cell 12 and/or the measurement signal, the control unit 16 can optionally determine a fill level and/or that a limit level of the medium has been reached.

Furthermore, the pressure transmitter system 10 has an oscillating element 30 which is arranged and/or fastened on a side of the process diaphragm 28 facing the filling medium 24 . In the example of 1 the oscillating element 30 is arranged centrally, for example in the area of a central axis of the process diaphragm 28, on the process diaphragm 28, but it can also be mounted at any other point. The oscillating element 30 can, for example, be welded and/or glued to the process diaphragm 28 . The vibrating element 30 can be a piezoelectric vibrating element 30, for example. The oscillating element 30 can also be an inductive oscillating element 30, which can have one or more coils, and/or a capacitive oscillating element 30, which can have one or more capacitors.

The oscillating element 30 is coupled to the control unit 16 via a suitable electrical line. The control unit 16 can control the oscillating element 30 with an electrical signal, for example in the form of a pulse packet. In this case, the electrical signal can have information about at least one excitation frequency, at least one excitation amplitude and/or at least one excitation duration. Such information can be stored, for example, in a memory 18 of the control unit 16 . Based on the electrical signal, the oscillating element 30 then excites the process membrane 28 to at least oscillate with the at least one excitation frequency, the at least one excitation amplitude and/or the at least one excitation duration.

After the excitation and/or after the end of the excitation, the oscillating element 30 detects the decay behavior of the at least one vibration of the process diaphragm 28 over at least part of a decay time period, within which the vibration completely decays. For this purpose, the oscillating element 30 converts the mechanical oscillation of the process membrane 28 into an electrical decay signal, which can be evaluated and/or processed by the control unit 16 .

The control unit 16 can determine a change in the pressure transmitter system 10 based on the decay signal, for example relative to a reference state of the pressure transmitter system 10. For determining the change in the pressure transmitter system 10, the control unit 16 can determine one or more parameters (or one or more parameters of one or more parameters) of the diaphragm seal system 10 and/or a change in one or more parameters (or parameters) relative to one or more reference values. The reference values can be stored in memory 18, for example. As a possible parameter, the control unit 16 can, for example, include at least part of a decay curve, at least one decay frequency of the vibration, at least one decay amplitude of the vibration, at least one resonance frequency of the process diaphragm 28, a thickness of the process diaphragm 28, a rigidity of the process diaphragm 28, an elasticity of the process diaphragm 28 , determine a deformation of the process diaphragm 28 and/or a filling pressure of the filling medium. The decay curve can be determined, for example, by determining the decay amplitudes of one or more decay frequencies over time. In this case, the control unit 16 can also derive further parameters from a parameter. For example, the thickness of the process membrane 28 can be determined based on the decay curve.

The control unit 16 can be set up, for example, to determine how quickly the vibration decays, with which frequency (or with which frequencies) and/or with which amplitude (or with which amplitudes) the process diaphragm 28 oscillates during the decay of the vibration . Based on a frequency and/or decay frequency determined in this way, the resonant frequency of the process diaphragm 28 can be determined, which in turn can allow conclusions to be drawn about the structural and/or mechanical properties of the process diaphragm 28, such as a thickness and/or a rigidity of the process diaphragm 28. Alternatively or additionally the control unit 16 can determine at least one excitation amplitude and/or at least one excitation frequency with which the process membrane 28 can be excited. This too can allow conclusions to be drawn about the resonant frequency of the process diaphragm 28 and/or its properties.

Furthermore, the control unit 16 can also analyze the pressure signal or measurement signal detected when the process diaphragm 28 is excited and/or de-excited in order to determine the change in the pressure transmitter system 10 . Based on an evaluation of the pressure signal of the pressure measuring cell 12 and the decay signal, a change in the pressure of the filling medium 24 and/or a loss of filling medium 24 can be determined, for example. When using the pressure signal of the pressure measuring cell 12, the pressure measuring cell 12 itself can also be checked with regard to its functionality.

Optionally, the control unit 16 can be set up to adapt one or more measurement parameters based on the determined change in the pressure transmitter system 10, based on at least one parameter and/or based on a change in at least one parameter. The measurement parameters can be stored in memory 18, for example. For example, the control unit 16 can carry out a parameterization if a change in the pressure transmitter system 10 has been determined. For example, a zero point of the pressure transmitter system 10 can be defined and/or changed as a function of at least one parameter, for example in order to counteract a change in the pressure of the filling medium 24 .

Furthermore, the control unit 16 can output a warning signal in response to a determined change in the pressure transmitter system 10, for example on a signal display 32 of the pressure transmitter system 10 and/or as an electrical warning signal. For example, at least one threshold value for at least one parameter can be stored in memory 18 . When the threshold value is reached, the control unit 16 can generate and/or output the warning signal.

Aspects of the diaphragm seal system 10 are summarized below. By attaching the oscillating element 30 to the process diaphragm 28, the latter can be excited in a targeted manner. The decay behavior, for example compared to a reference decay behavior or reference state, can be determined and/or evaluated by the control unit 16 . Conclusions about changes in the diaphragm seal system 10 can be drawn from this. The detection of this change can be derived from one or more parameters and/or their changes relative to reference values. Among other things, the decay curve after targeted excitation, a change in the resonant frequency of the process membrane 28, and/or a change in the amplitude of the oscillation can be determined. A stretching and/or stretching behavior of the process membrane 28 can also be determined.

If a change in the pressure transmitter system 10 is detected, a warning message can be issued. With this warning message, the user can initiate measures such as replacing the diaphragm seal system 10, cleaning the diaphragm seal system and/or adapting the process conditions to the technical data of the filling medium 24. Changes in the diaphragm seal system 10 can also cause a shift in the parameters of the process diaphragm 28 in the diaphragm seal system. The detection of the deviations can thus be a clear Allow term assessment of the condition of the diaphragm seal system 10.

The oscillating element 30, such as a piezoelectric element 30, is attached to the inside of the process diaphragm 28. The control unit 16 generates an electrical signal, e.g. In this phase, the oscillating element 30 works as a transmitter. The decay behavior of the process diaphragm 28 can now be detected by the oscillating element 30 and forwarded to the control unit 16 as an electrical signal or decay signal. In this phase, the oscillating element 30 works as a receiver. By comparing one or more parameters, which can be derived from the decay signal, with reference values, deviations and/or changes can be detected and corresponding warnings and/or fault messages can be output.

2 shows a sectional view of a pressure transmitter system 10 according to a further exemplary embodiment. Unless otherwise described, the diaphragm seal system 10 of 2 the same elements and / or functions as the diaphragm seal system 10 of 1 on.

At the in 2 The exemplary embodiment shown has the pressure transmitter system 10 on two oscillating elements 30 which are arranged symmetrically to a central axis of the process diaphragm 28 . One or more further oscillating elements 30 can also be provided. In particular, the diaphragm seal system 10 of 2 also have an oscillating element 30 arranged centrally on the process diaphragm 28, as with reference to FIG 1 described. Additional information and/or parameters of the process diaphragm 28 can be determined by using a plurality of oscillating elements 30 at different positions of the process diaphragm 28 . For example, a stretching and/or stretching behavior of the process membrane 28 can be determined in one or more spatial directions.

The oscillating elements 30 detect the decay behavior at different positions of the process diaphragm 28 and each output a decay signal that correlates with the decay behavior detected at the respective position. The control unit 16 can control one or more of the oscillating elements 30 in order to generate the at least one oscillation. When a plurality of oscillating elements 30 are activated, they can be excited with pulse packets which are identical or different from one another. The oscillating elements 30 can also be controlled at the same time or at different times in relation to one another. The control unit 16 can also evaluate one or more decay signals from one or more oscillating elements 30 in order to determine the change in the pressure transmitter system 10 . For example, the decay signals of different oscillating elements 30 can be compared with one another, which can allow further conclusions to be drawn about the state of the process diaphragm 28 .

3 shows a flowchart to illustrate steps of a method for determining a change in a pressure transmitter system 10 according to an embodiment. The diaphragm seal system 10 can be one of the with reference to 1 and 2 act described diaphragm seal systems 10.

In a step S1, a process diaphragm 28 of the pressure transmitter system 10 is excited to at least oscillate with an oscillating element 30.

In a further step S2, the oscillating element 30 is used to detect the decay behavior of the at least one vibration of the process diaphragm 28 while generating a decay signal that correlates with the decay behavior.

In a further step S3, a change in the pressure transmitter system 10 is determined based on an evaluation and/or processing of the decay signal with a control unit 16 of the pressure transmitter system 10.

In addition, it should be noted that "comprising" and "having" do not exclude other elements or steps and the indefinite articles "a" or "an" do not exclude a plurality.

Furthermore, it should be pointed out that features or steps that have been described with reference to one of the above exemplary embodiments can also be used in combination with other features or steps of other exemplary embodiments described above. Any reference signs in the claims should not be construed as limitations.

Claims (15)

Pressure transmitter system (10) for determining a pressure of a medium, the pressure transmitter system (10) having: a pressure measuring cell (12) for outputting a pressure signal which is proportional to a pressure present at the pressure measuring cell (12); a diaphragm seal (20) with a hydraulic channel (22) and a process membrane (28), wherein the hydraulic channel (22) extends between the pressure measuring cell (12) and the process diaphragm (28) and is designed to store a filling medium (24), so that a process pressure of the medium acting on the process diaphragm (28) is released via the filling medium (24) can be at least partially transferred to the pressure measuring cell (12); at least one oscillating element (30) which is coupled to the process diaphragm (28) and which is designed to excite the process diaphragm (28) to vibrate at least, to detect a decay behavior of the at least one vibration of the process diaphragm (28) and to generate decay signal correlating decay behavior; and a control unit (16) which is coupled to the oscillating element (30) and which is set up to determine a change in the pressure transmitter system (10) based on the decay signal. Diaphragm seal system (10) according to claim 1 , wherein the at least one oscillating element (30) is set up to excite the process membrane (28) directly and/or directly to the at least one oscillation. Pressure transmitter system (10) according to one of the preceding claims, wherein the at least one oscillating element (30) is mechanically coupled to the process membrane (28). Pressure transmitter system (10) according to one of the preceding claims, wherein the at least one oscillating element (30) is arranged on a side of the process membrane (28) facing the hydraulic channel (22); and or wherein the at least one oscillating element (30) is arranged centrally on the process diaphragm (28). Pressure transmitter system (10) according to one of the preceding claims, wherein the control unit (16) is set up to determine the change in the pressure transmitter system (10) relative to a reference state of the pressure transmitter system. Pressure transmitter system (10) according to one of the preceding claims, wherein the control unit (16) is set up to determine the change in the pressure transmitter system (10) based on a determination of at least one parameter of the pressure transmitter system (10); and or wherein the control unit (16) is set up to determine the change in the pressure transmitter system (10) based on determining a change in at least one parameter of the pressure transmitter system (10) relative to at least one reference value of the at least one parameter. Diaphragm seal system (10) according to claim 6 , wherein the at least one reference value of the at least one parameter is stored in a memory (18) of the pressure transmitter system (10). Diaphragm seal system (10) according to one of Claims 6 or 7 , wherein the at least one parameter is at least a part of a decay curve, at least one decay frequency, at least one decay amplitude, at least one resonant frequency of the process diaphragm (28), a thickness of the process diaphragm (28), a rigidity of the process diaphragm (28), an elasticity of the process diaphragm ( 28), a deformation of the process diaphragm (28), a quality of the filling medium (24), a property of the filling medium (24) and/or a filling pressure of the filling medium (24). Pressure transmitter system (10) according to one of the preceding claims, wherein the control unit (16) is set up to excite the process diaphragm (28) in a pulsed manner with at least one excitation frequency, at least one excitation amplitude and/or at least one excitation time period to produce the at least one oscillation. Pressure transmitter system (10) according to one of the preceding claims, wherein the control unit (16) is set up to determine at least one excitation amplitude and/or at least one excitation frequency with which the process diaphragm (28) can be excited. Pressure transmitter system (10) according to one of the preceding claims, wherein the control unit (16) is further set up to output a warning signal in response to a determined change in the pressure transmitter system (10). Pressure transmitter system (10) according to one of the preceding claims, wherein the control unit (16) is also set up to carry out a calibration and/or parameterization of the pressure transmitter system (10) in response to a determined change in the pressure transmitter system (10). Pressure transmitter system (10) according to one of the preceding claims, wherein the at least one oscillating element (30) is a piezoelectric oscillating element, an inductive oscillating element and/or a capacitive oscillating element. Pressure transmitter system (10) according to one of the preceding claims, wherein the pressure transmitter system (10) has a plurality of oscillating elements (30) which are designed to detect the decay behavior of the at least one vibration at different positions of the process diaphragm (28) and one with the decay behavior generate a correlating decay signal. Method for determining a change in a pressure transmitter system (10) according to one of the preceding claims, the method comprising: exciting, with an oscillating element (30), a process membrane (28) of the pressure transmitter system (10) to at least one oscillation; Detecting, with the oscillating element (30), a decay behavior of the at least one vibration of the process membrane (28) while generating a decay signal correlating with the decay behavior; and determining a change in the pressure transmitter system (10) based on an evaluation of the decay signal with a control unit (16) of the pressure transmitter system (10)

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