DE102019209353A1 - Diaphragm seal system with monitoring function - Google Patents

Abstract

A diaphragm seal system (10) for determining a pressure of a medium is described, which has a pressure measuring cell (12) and a diaphragm seal (20) with a hydraulic channel (22) and a process membrane (28), the hydraulic channel being located between the pressure measuring cell (12) and the process diaphragm (28) extends. Furthermore, the diaphragm seal system has at least one oscillating element (30) which is coupled to the process diaphragm (28) and which is designed to excite the process diaphragm to at least one oscillation, to detect a decay behavior of the at least one oscillation of the process diaphragm (28) and a to generate a decay signal correlating with the decay behavior. A control unit (16) is provided to determine a change in the diaphragm seal system (10) based on the decay signal.

Description

Field of invention

The invention relates generally to the field of sensor technology, in particular in process automation and / or the process industry. In particular, the invention relates to a diaphragm seal system for determining a pressure of a medium with an integrated monitoring function, for example for monitoring and / or checking the functionality of the diaphragm seal system. The invention also relates to a method for determining a change in such a diaphragm seal 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 membrane, one side of which can face the medium. The process membrane can also be hydraulically coupled to the pressure measuring cell, so that a process pressure exerted by the medium on the process membrane can be at least partially transmitted hydraulically to the pressure measuring cell. Based on the pressure applied to the pressure measuring cell, a pressure signal and / or a measurement signal can be generated and / or output which is proportional to the pressure applied to the pressure measuring cell and / or proportional to the process pressure applied to the process membrane, i.e. the pressure of the medium. 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 materials of conventional pressure sensors can attack. A high chemical resistance can be provided in diaphragm seal systems through the use of 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.

Summary of the invention

With embodiments of the invention, an improved diaphragm seal 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 process pressure.

This is made possible in particular by the subjects of the independent patent claims. Further developments of the invention result from the subclaims 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 pipe and / or any other container. The diaphragm seal system has a pressure measuring cell, also called a pressure transmitter, for outputting a pressure signal which is proportional to a pressure applied to the pressure measuring cell. The pressure measuring cell can, for example, have a ceramic or a metallic membrane, the deflection of which can be used to determine the pressure applied. Furthermore, the diaphragm seal system has a diaphragm seal with a hydraulic channel and a process membrane, the hydraulic channel extending between the pressure measuring cell and the process membrane and being designed to store a filling medium so that a process pressure of the medium acting on the process membrane is at least partially over the filling medium can be transferred to the pressure measuring cell. The filling medium can be subjected to a pressure and / or form. Furthermore, the diaphragm seal system has at least one oscillating element which is coupled to the process membrane and which is designed to excite the process membrane to at least one oscillation, to detect a decay behavior of the at least one oscillation of the process membrane and to generate a decay signal that correlates with the decay behavior. Furthermore, the diaphragm seal system has a control unit which is coupled to the oscillating element and which is set up to change (and / or change) the diaphragm seal system and / or a change (and / or change) at least one property of the diaphragm seal system based on the decay signal to be determined, for example based on a processing and / or processing of the decay signal.

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

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

In the context of the present disclosure, the vibrating element can generally designate a vibration generator and / or a vibration receiver. In general, the vibrating element can be set up to excite the process membrane to the at least one oscillation, in particular to mechanically excite the oscillation, based on an electrical signal, for example a signal and / or control signal of 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 control the vibrating element with an electrical signal, for example a control signal, and the vibrating element can, based on the electrical signal, excite the process membrane (e.g. mechanically) to the at least one vibration, in particular excite it in a targeted manner. In this case, the vibrating element can work as a transmitter. The at least one oscillation can take place, for example, by an excitation, in particular a mechanical and / or targeted excitation, of the process membrane 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 stimulate the process membrane via the vibrating element in a pulse-like manner with at least one excitation frequency, at least one excitation amplitude and / or at least one excitation time period for the at least one oscillation. For example, the control unit can send a pulse packet as an electrical signal to the vibrating element in order to excite the process membrane in accordance with the pulse packet.

After the process membrane has been excited, the vibrating element can also determine the mechanical vibration of the process membrane while the vibration is decaying, detect the decay behavior of the vibration of the process membrane and convert and / or convert it into the decay signal, which can be evaluated by the control unit. In this case, the vibrating element can work as a receiver. The decay behavior of the at least one oscillation of the process membrane can generally denote a decay of the oscillation over time. The decay behavior can, for example, be a decrease and / or change in at least one amplitude (or decay amplitude) of the oscillation over time, at least one decay frequency over time, at least one change in the decay frequency over time, a frequency composition of the oscillation during the decay and / or comprise at least one decay period (eg for at least one decay frequency). Such and other variables and / or information that characterize or describe 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. Diaphragm seal systems can be used for 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, therefore, under certain circumstances wear and / or erosion of Material of the process diaphragm come due to chemical reactions and / or mechanical effects. The process membrane can also be deformed and / or destroyed by the action of mechanical force, for example by pressure surges, steam hammers 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 a change in the pressure of the filling medium in the diaphragm seal. 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 influence the measurement of the process pressure of the medium. When the pressure or pre-pressure of the filling medium in the diaphragm seal drops, 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 restricted temperature range. If this temperature range is exceeded, the filling medium begins to outgass the 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 diaphragm seal system in the zero point and / or in the rest position of the diaphragm seal system. With conventional diaphragm seal systems, this drift cannot be recognized by the diaphragm seal system and thus by the user. This can require calibration of the pressure measuring cell and / or the diaphragm seal system at regular time intervals. A total failure of the diaphragm seal system and / or an escape of filling medium can also occur.

The diaphragm seal system according to the invention with the at least one oscillating element, however, advantageously allows such changes in the diaphragm seal system to be determined. In particular, this enables early detection of the change in the diaphragm seal system and / or early detection of a potential malfunction. This in turn allows countermeasures to be initiated in good time. Regular calibration of the pressure transmitter system according to the invention can also advantageously be dispensed with and / or the frequency of calibration can be reduced.

According to one embodiment, the at least one oscillating element is set up to excite the process membrane directly and / or directly with (or to the) at least one oscillation. The vibrating element can, for example, be coupled to the process membrane in such a way that it can excite the process membrane directly and / or directly to the at least one oscillation and / or can impress the at least one oscillation on the process membrane. In other words, the vibrating element can be designed not to induce the process membrane to vibrate 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 membrane. For example, the at least one oscillating element can be arranged and / or fastened on a side of the process membrane facing the hydraulic channel. The vibrating 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 vibrating element can be glued and / or welded to the process membrane.

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

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

The control unit can be set up, for example, to derive and / or determine the at least one characteristic variable (or the characteristic value of the characteristic variable) from the decay signal. Alternatively or additionally, the control unit is set up to determine the change in the diaphragm seal system based on a determination of a change in at least one characteristic variable (or at least one characteristic value of the at least one characteristic variable) of the diaphragm seal system relative to at least one reference value of the at least one characteristic variable, the at least a reference value of the at least one parameter can be stored, for example, in a memory of the diaphragm seal system. 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 change one or more parameters of the process diaphragm, for example, such as rigidity and / or a thickness of the process membrane. The change in the at least one parameter can also influence the decay behavior of the oscillation, so that the change in the diaphragm seal 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 oscillation, at least one decay frequency of the oscillation, at least one decay amplitude of the oscillation, at least one resonance frequency of the process membrane, a thickness of the process membrane, a rigidity of the process membrane, an elasticity of the process membrane, a Deformation of the process membrane, a degree of deformation of the process membrane, 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 oscillation of the process membrane over time, an amplitude curve of the oscillation over time and / or a frequency curve of the oscillation 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 diaphragm seal system and / or monitoring of the functionality of the diaphragm seal 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 be excited and / or can be excited. This, too, can enable conclusions to be drawn about a change in the diaphragm seal system, for example about a change in the resonance frequency of the process membrane and / or a change in the pressure of the filling medium.

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

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

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

The control unit can, for example, control one or more of the oscillating elements in order to generate the at least one oscillation. When controlling several oscillating elements, these can be excited with identical or different pulse packets and / or electrical signals. Several vibrating 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 diaphragm seal system. For example, the decay signals from 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.

Another aspect relates to a method for determining a change in a diaphragm seal system, as described above and below. The process has the following steps:

• - Exciting, with a vibrating element, a process membrane of the diaphragm seal system to at least one vibration;
• - Detecting, with the vibrating element, a decay behavior of the at least vibration of the process membrane, for example after excitation and / or after targeted excitation;
• - Generating a decay signal correlating with the decay behavior; and
• - Determining a change in the diaphragm seal system based on an evaluation of the decay signal with a control unit of the diaphragm seal system.

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

Another aspect relates to a program element which, when it is executed on a control unit of a diaphragm seal system and / or a processor of the control unit, causes the diaphragm seal system to carry out steps of the method as described above and below. The program element can, for example, be stored in a memory of the diaphragm seal system and / or comprise corresponding software instructions.

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

In the following, exemplary embodiments of the invention are described with reference to the figures.

Figure 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 diaphragm seal system according to an embodiment.

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

Detailed description of exemplary embodiments

1 shows a sectional view of a diaphragm seal system 10 according to an embodiment.

The diaphragm seal system 10 has a pressure measuring cell 12 with a pressure transmission element 14th , such as a membrane 14th , on. The pressure measuring cell 12 For example, a ceramic pressure measuring cell with a ceramic membrane 14th or a metallic pressure measuring cell with a metallic membrane 14th be. The pressure measuring cell 12 is set up to one with an outside on the membrane 14th to output a pressure signal correlating to the applied pressure. The pressure measuring cell 12 suitable electronics 16 and / or control unit 16 have or be coupled to it, which can convert the pressure signal into an (electrical) measurement signal, for example. Via an electrical line 17th of the diaphragm seal system 10 the measurement signal can be transmitted and / or transmitted to a higher-level unit. A power supply for the diaphragm seal system can also be used 10 over the line 17th respectively.

Furthermore, the diaphragm seal system 10 a diaphragm seal 20th (e.g. with a base body) and a process membrane 28 on. The process membrane 28 is hydraulic with the pressure measuring cell 12 and / or the membrane 14th the pressure measuring cell 12 coupled. This allows a mechanical decoupling of the process membrane 28 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 be bent and / or curved at least in a partial area, for example sinusoidal.

The process membrane 28 is on a process connection 26th arranged. Via the process connection 26th can the diaphragm seal system 10 be mounted on a container 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 membrane 28 is at least partially elastically deformable, with a deformation and / or deflection of the process membrane 28 representative of the on the process membrane 28 acting process pressure of the medium.

The diaphragm seal 20th also has a hydraulic channel 22nd on which with a filling medium 24 is filled. The filling medium 24 can do this with a Pressure and / or a pre-pressure can be applied. With the filling medium 24 it can be, for example, an oil, a hydraulic medium, a high-temperature oil and / or a medicinal white oil. The hydraulic channel 22nd extends from the pressure measuring cell 12 up to one side of the process diaphragm 28 so that the pressure measuring cell 12 via the hydraulic channel 22nd with the process membrane 28 is in fluid communication. One through the medium to the process membrane 28 Process pressure exerted can be applied via the filling medium 24 at least partially on the pressure measuring cell 12 be transmitted. The pressure signal and / or the measurement signal determined in the process is thus proportional to that at the process diaphragm 28 applied process pressure. Based on the pressure signal from the pressure measuring cell 12 and / or the measurement signal, the control unit 16 optionally determine a fill level and / or the reaching of a limit level of the medium.

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

The vibrating element 30th is connected to the control unit via a suitable electrical line 16 coupled. The control unit 16 can the vibrating element 30th control with an electrical signal, for example in the form of a pulse packet. The electrical signal can have information about at least one excitation frequency, at least one excitation amplitude and / or at least one excitation time period. Such information can be in a memory 18th the control unit 16 be deposited. The vibrating element excites based on the electrical signal 30th then the process membrane 28 to at least one oscillation 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 termination of the excitation, the oscillating element detects 30th the decay behavior of the at least one oscillation of the process membrane 28 over at least part of a decay time period within which the oscillation completely decays. For this purpose, the vibrating element converts 30th the mechanical vibration of the process membrane 28 into an electrical decay signal sent by the control unit 16 can be evaluated and / or processed.

The control unit 16 can change the diaphragm seal system based on the decay signal 10 determine, for example relative to a reference state of the diaphragm seal system 10 . To determine the change in the diaphragm seal system 10 can the control unit 16 for example one or more parameters (or one or more parameters of one or more parameters) of the diaphragm seal system 10 and / or determine a change in one or more parameters (or parameters) relative to one or more reference values. The reference values can for example be in the memory 18th be deposited. The control unit 16 for example at least part of a decay curve, at least one decay frequency of the oscillation, at least one decay amplitude of the oscillation, at least one resonance frequency of the process membrane 28 , a thickness of the process diaphragm 28 , a rigidity of the process diaphragm 28 , an elasticity of the process membrane 28 , a deformation of the process diaphragm 28 and / or determine 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. The control unit 16 can derive further parameters from one parameter. For example, the thickness of the process diaphragm 28 can be determined based on the decay curve.

The control unit 16 can for example be set up to determine how quickly the oscillation decays, with which frequency (or with which frequencies) and / or with which amplitude (or with which amplitudes) the process membrane 28 fades as the oscillation dies down. Based on such a determined frequency and / or decay frequency, the resonance frequency of the process membrane can thus 28 can be determined, which in turn draws conclusions about the structural and / or mechanical properties of the process membrane 28 may allow, such as a thickness and / or a rigidity of the process diaphragm 28 . Alternatively or additionally, the control unit 16 determine at least one excitation amplitude and / or at least one excitation frequency with which the process membrane 28 is stimulable. This, too, can draw conclusions about the resonance frequency of the process diaphragm 28 and / or allow their properties.

Furthermore, the control unit 16 also when exciting and / or de-energizing the process membrane 28 detected pressure signal or measurement signal analyze the change in the diaphragm seal system 10 to determine. Based on an evaluation of the pressure signal from the pressure measuring cell 12 and the decay signal can, for example, be a change in the pressure of the filling medium 24 and / or a loss of fill medium 24 be determined. If the pressure signal of the pressure measuring cell is used 12 the pressure measuring cell 12 themselves are checked with regard to their functionality.

Optionally, the control unit 16 be set up based on the determined change in the diaphragm seal system 10 to adjust one or more measurement parameters based on at least one parameter and / or based on a change in at least one parameter. The measurement parameters can for example in the memory 18th be deposited. For example, the control unit 16 carry out a parameterization if there is a change in the diaphragm seal system 10 was determined. For example, a zero point of the diaphragm seal system 10 can be set and / or changed as a function of at least one parameter, for example by a change in the pressure of the filling medium 24 to counteract.

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

The following are aspects of the diaphragm seal system 10 summarized. By attaching the vibrating element 30th on the process membrane 28 this can be specifically stimulated. The decay behavior, for example compared to a reference decay behavior or reference state, can be provided by the control unit 16 determined and / or assessed. This allows conclusions to be drawn about changes in the diaphragm seal system 10 to be pulled. 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 can change the resonance frequency of the process membrane after targeted excitation 28 , and / or a change in the amplitudes of the oscillation can be determined. A stretching and / or stretching behavior of the process membrane can also 28 be determined.

Will a change in the diaphragm seal system 10 detected, a warning message can be issued. With this warning the user can initiate measures, such as the diaphragm seal system 10 to replace, to clean the diaphragm seal system and / or the process conditions to the technical data of the filling medium 24 adapt. Changes in the diaphragm seal system 10 a shift in the parameters of the process membrane 28 cause in the diaphragm seal system. The detection of the deviations can thus enable a clear assessment of the condition of the diaphragm seal system 10 allow.

The vibrating element 30th , such as a piezo element 30th , is on the inside of the process diaphragm 28 attached. The control unit 16 generates an electrical signal, for example a pulse packet, and thus excites the vibrating element 30th . The resulting movement of the vibrating element 30th brings the process membrane 28 in vibration. The vibrating element works in this phase 30th as a sender. The decay behavior of the process membrane 28 can now through the vibrating element 30th and as an electrical signal or decay signal to the control unit 16 be passed on. The vibrating element works in this phase 30th as receiver. For example, by comparing one or more parameters, which can be derived from the decay signal, with reference values, deviations and / or changes can be recognized and corresponding warning and / or fault messages can be output.

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

The in 2 The embodiment shown has the diaphragm seal system 10 two oscillating elements 30th which is symmetrical about a central axis of the process diaphragm 28 are arranged. One or more further oscillating elements can also be used 30th be provided. In particular, the diaphragm seal system 10 the 2 also one in the middle of the process membrane 28 arranged vibrating element 30th exhibit, as with reference to 1 described. By using several vibrating elements 30th at different positions of the process diaphragm 28 can provide further information and / or parameters of the process membrane 28 be determined. For example, such a stretching and / or stretching behavior of the process membrane 28 can be determined in one or more spatial directions.

The oscillating elements 30th detect the decay behavior at different positions on the process membrane 28 and each output a decay signal that correlates with the decay behavior detected at the respective position. The control unit 16 can be one or more of the oscillating elements 30th drive to generate the at least one oscillation. When controlling several vibrating elements 30th these can be excited with identical or different pulse packages. The oscillating elements 30th can be controlled at the same time or at different times. The control unit 16 can also include one or more decay signals from one or more vibrating elements 30th evaluate the change in the diaphragm seal system 10 to investigate. For example, the decay signals from different oscillating elements 30th can be compared with each other, which allows further conclusions to be drawn about the condition of the process membrane 28 can enable.

3 shows a flowchart to illustrate steps of a method for determining a change in a diaphragm seal system 10 according to an embodiment. With the diaphragm seal system 10 may be one of the related to 1 and 2 diaphragm seal systems described 10 act.

In one step S1 comes with a vibrating element 30th a process membrane 28 of the diaphragm seal system 10 excited to at least one oscillation.

In a further step S2 becomes with the vibrating element 30th the decay behavior of the at least one oscillation of the process membrane 28 is detected while generating a decay signal correlating with the decay behavior.

In a further step S3 becomes a change in the diaphragm seal system 10 based on evaluating and / or processing the decay signal with a control unit 16 of the diaphragm seal system 10 determined.

In addition, it should be noted that “comprising” and “having” do not exclude any other elements or steps and the indefinite articles “a” or “a” do not exclude a multiplicity.

It should also 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. Reference signs in the claims are not to be regarded as restrictions.

Claims (15)

Diaphragm seal system (10) for determining a pressure of a medium, the diaphragm seal system (10) having: a pressure measuring cell (12) for outputting a pressure signal which is proportional to a pressure applied to the pressure measuring cell (12); a pressure transmitter (20) with a hydraulic channel (22) and a process membrane (28), wherein the hydraulic channel extends between the pressure measuring cell (12) and the process membrane (28) and is designed to store a filling medium (24) so that a process pressure of the medium acting on the process membrane (28) can be at least partially transferred to the pressure measuring cell (12) via the filling medium (24); at least one oscillating element (30) which is coupled to the process membrane (28) and which is designed to excite the process membrane to at least one oscillation, to detect a decay behavior of the at least one oscillation of the process membrane (28) and a decay signal that correlates with the decay behavior to create; and a control unit (16) which is coupled to the oscillating element (30) and which is set up to determine a change in the diaphragm seal system (10) based on the decay signal. Diaphragm seal system (10) Claim 1 wherein the at least one oscillating element (30) is set up to excite the process membrane directly and / or immediately to the at least one oscillation. Diaphragm seal 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). Diaphragm seal 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 membrane (28). Diaphragm seal system (10) according to one of the preceding claims, wherein the control unit (16) is set up to determine the change in the diaphragm seal system relative to a reference state of the diaphragm seal system. Diaphragm seal system (10) according to one of the preceding claims, wherein the control unit (16) is set up to determine the change in the diaphragm seal system based on a determination of at least one parameter of the diaphragm seal system; and / or wherein the control unit (16) is set up to relative to the change in the diaphragm seal system based on a determination of a change in at least one characteristic variable of the diaphragm seal system to determine at least one reference value of the at least one parameter. Diaphragm seal system (10) Claim 6 , wherein the at least one reference value of the at least one parameter is stored in a memory (18) of the diaphragm seal system. Diaphragm seal system (10) according to one of the Claims 6 or 7th , 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 resonance frequency of the process membrane (28), a thickness of the process membrane (28), a rigidity of the process membrane (28), an elasticity of the process membrane ( 28), a deformation of the process membrane (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). Diaphragm seal system (10) according to one of the preceding claims, wherein the control unit (16) is set up to excite the process membrane (28) in a pulse-like manner with at least one excitation frequency, at least one excitation amplitude and / or at least one excitation time period for the at least one oscillation. Diaphragm seal 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 membrane (28) can be excited. Diaphragm seal system (10) according to one of the preceding claims, wherein the control unit (16) is further configured to output a warning signal in response to a determined change in the diaphragm seal system. Diaphragm seal system (10) according to one of the preceding claims, wherein the control unit (16) is further set up to carry out a calibration and / or parameterization of the diaphragm seal system in response to a determined change in the diaphragm seal system. Diaphragm seal 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. Diaphragm seal system (10) according to one of the preceding claims, wherein the diaphragm seal system has several oscillating elements (30) which are designed to detect the decay behavior of the at least one oscillation at different positions of the process membrane (28) and in each case to a decay signal correlating with the decay behavior produce. Method for determining a change in a diaphragm seal system (10) according to one of the preceding claims, the method comprising: Exciting, with a vibrating element (30), a process membrane (28) of the diaphragm seal system to at least one vibration; Detecting, with the oscillating element (30), a decay behavior of the at least one oscillation of the process membrane (28) while generating a decay signal correlating with the decay behavior; and Determining a change in the diaphragm seal system (10) based on an evaluation of the decay signal with a control unit (16) of the diaphragm seal system.

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