Abstract: A valve that can be actuated by a position controller via a drive, wherein the position controller has a housing and is fastened to the valve by the housing. A first temperature sensor and a second temperature sensor are attached on or in the housing. As a result of the position of both sensors, the temperature measured using the first temperature sensor is more readily influenced by the valve and the temperature registered by the second temperature sensor is more readily influenced by the environment. If a gas leak occurs in the valve, a temperature difference occurs that is evaluated for diagnosis of a leak. The diagnostic system is particularly easy to minor implement with minimal effort.

Abstract: A diagnostic system and a diagnostic method for a valve, particularly a closing valve or a control valve, which is actuatable by a drive and is installed in a pipeline. Using a sensor, the pressures in the inlet side of the pipeline are detected and compared with a first reference value in an evaluation device while the valve is closed. The solid-borne sound level is measured using a sensor, and compared with a second reference value in the evaluation device. A signal for displaying leakage exceeding the allowable amount is output if the sound level exceeds the second reference value and if the pressure in the inlet side is smaller than or equal to the first reference value. A characteristic curve field is used to determine the first reference value of the pressure, the parameters thereof being the Kv value and the leakage class of the valve.

Abstract: A valve that can be actuated by a position controller via a drive, wherein the position controller has a housing and is fastened to the valve by the housing. A first temperature sensor and a second temperature sensor are attached on or in the housing. As a result of the position of both sensors, the temperature measured using the first temperature sensor is more readily influenced by the valve and the temperature registered by the second temperature sensor is more readily influenced by the environment. If a gas leak occurs in the valve, a temperature difference occurs that is evaluated for diagnosis of a leak. The diagnostic system is particularly easy to minor implement with minimal effort.

Abstract: There is described a method and device for measurement of the specific density of a gaseous or liquid medium, whereby a pulsed acoustic signal is injected into the measured medium by means of a transmitting transducer, the signal is detected by a receiver transducer, after passing over a measured path, whereupon the acoustic impedance Z is automatically determined in an analytical device by comparison of a curve for the currently measured received signal with reference curves, predetermined for various values of the acoustic impedances stored for each value of the acoustic impedance, whereby the propagation speed c of the acoustic signal in the medium is determined and the density p of the medium is calculated as the quotient from the acoustic impedance Z and the propagation speed c. The method is preferably of application to an ultrasound mass flow measurement device and hence has the advantage that no additional density sensor is required, nevertheless permitting a robust and precise measurement of density.

Abstract: A diagnostic system and a diagnostic method for a valve, particularly a closing valve or a control valve, which is actuatable by a drive and is installed in a pipeline. Using a sensor, the pressures in the inlet side of the pipeline are detected and compared with a first reference value in an evaluation device while the valve is closed. The solid-borne sound level is measured using a sensor, and compared with a second reference value in the evaluation device. A signal for displaying leakage exceeding the allowable amount is output if the sound level exceeds the second reference value and if the pressure in the inlet side is smaller than or equal to the first reference value. A characteristic curve field is used to determine the first reference value of the pressure, the parameters thereof being the Kv value and the leakage class of the valve.

Abstract: There is described a diagnosis method and a system including a structure-born noise sensor which transmits, in a bandpass filtered manner, a measuring signal based on the mechanical resonance frequency and capacity thereof and on an inductance and an evaluating device in which the frequency, at which the measuring signal level exceeds a predetermined threshold value, is defined and which is used for producing an error signal, when the frequency exceeds a second predetermined threshold value. As far as the diagnosis performance requires a small number of electronic components and a low power supply, the diagnostic is integrated into existing devices, in particular into process instrumentation field devices for which a restricted quantity of operating power is available. The method and the system are used for identifying a valve leakage with the aid of an electro-pneumatic positional regulator.

Abstract: There is described a diagnosis method and system including a sensor for structure-borne noise which emits a measuring signal in a bandwidth-filtered manner due to its mechanical resonant frequency, capacitance and inductance. The system also includes an evaluation device in which the measuring signal is undersampled and which outputs an error signal should the undersampled measuring signal exceed a defined threshold value. The system requires only a small number of electronic components and only a little power supply capacity. The system thereby allows diagnosis to be carried out without complication in existing devices, especially in field devices of process instrumentation for which only a limited amount of operating power is available. The method and system are especially advantageous for the recognition of valve leakage with an electropneumatic position controller.

Abstract: A diagnostic system and method for a valve, especially a check valve of a positive displacement pump, including at least one solid-borne sound sensor is provided. A first value of a parameter of a sound signal recorded in the closed state of the valve and a second value of a parameter of a sound signal recorded in the open state of a valve are determined essentially. A signal indicating a disturbance is issued if the deviation between the first value and the second value exceeds a predefined threshold value, resulting in particularly good insensitivity.

Abstract: An acoustic pick-up, particularly an ultrasonic pick-up for acoustically diagnosing machines, for example, for detecting leakage in valves or for diagnosing positions, comprising a piezoelectric measuring element and an electronic circuit that processes the measurement signal into a form that is suited for transmission to an evaluation device. In order that the acoustic pick-up can function without an external auxiliary power supply, means are provided by means of which auxiliary power required for operating the electronic circuit can be generated from the acoustic signal to be picked up.

Abstract: A diagnostic system and method for a valve, especially a check valve of a positive displacement pump, including at least one solid-borne sound sensor is provided. A first value of a parameter of a sound signal recorded in the closed state of the valve and a second value of a parameter of a sound signal recorded in the open state of a valve are determined essentially. A signal indicating a disturbance is issued if the deviation between the first value and the second value exceeds a predefined threshold value, resulting in particularly good insensitivity.

Abstract: A diagnostic system, for a valve (2), having a sensor (12) that senses structure-borne noise and having a device (14) for evaluating a measurement signal (13) of the structure-borne noise. During a calibration process, a first progression of the measurement signal is sensed for the closed position of the valve (2) and a first value (w1) of a characteristic is determined. To simulate leakage noise, the valve (2) is nearly closed during operation, a second progression of the measurement signal is sensed and a second value (w2) is determined. If the deviation of the second value from the first value is sufficiently large, a diagnosis is possible. A third progression of the measurement signal is sensed for the closed position of the valve as in an installed condition, and a third value (w3) is determined. If the deviation of the third value (w3) from the first value (w1) is too great, and if a diagnosis has been identified as being possible, then the system deduces that the valve leaks.

Abstract: A diagnostic system, for a valve (2), having a sensor (12) that senses structure-borne noise and having a device (14) for evaluating a measurement signal (13) of the structure-borne noise. During a calibration process, a first progression of the measurement signal is sensed for the closed position of the valve (2) and a first value (w1) of a characteristic is determined. To simulate leakage noise, the valve (2) is nearly closed during operation, a second progression of the measurement signal is sensed and a second value (w2) is determined. If the deviation of the second value from the first value is sufficiently large, a diagnosis is possible. A third progression of the measurement signal is sensed for the closed position of the valve as in an installed condition, and a third value (w3) is determined. If the deviation of the third value (w3) from the first value (w1) is too great, and if a diagnosis has been identified as being possible, then the system deduces that the valve leaks.

Abstract: A device for measuring the specific density of a gaseous or liquid medium (8) having an acoustic transducer (1), which is active on both sides, and further having cylindrical delay paths (4, 5) as well as a ring (6) in which the acoustic transducer (1) is embedded. The diameter of the acoustic transducer (1) is selected such that it is smaller than the diameter of the delay paths (4, 5) so that diffracted waves generated in the area of the edge of the acoustic transducer generate fewer parasitic echoes and surface waves on the boundary surfaces (7, 9) resulting in less corruption of the measured result.

Abstract: The invention relates to a diagnostic system and method, especially for a valve (2) that can be actuated by a positioner (9) via a drive (6). The system utilizes a sensor (12) for recording structure-related sound and has a device (14) for evaluating a recorded measurement signal (13). A spectral region greater than 50 kHz is evaluated for conducting fault recognition. A fault indication signal is generated if the intensity of the measurement signal in this spectral region exceeds a defined threshold value. The sound caused by cavitation is primarily evaluated for conducting fault recognition.

Abstract: The invention relates to a diagnostic system and method, especially for a valve (2) that can be actuated by a positioner (9) via a drive (6). The system utilizes a sensor (12) for recording structure-related sound and has a device (14) for evaluating a recorded measurement signal (13). A spectral region greater than 50 kHz is evaluated for conducting fault recognition. A fault indication signal is generated if the intensity of the measurement signal in this spectral region exceeds a defined threshold value. The sound caused by cavitation is primarily evaluated for conducting fault recognition.

Abstract: A device for measuring the specific density of a gaseous or liquid medium (8) having an acoustic transducer (1), which is active on both sides, and further having cylindrical delay paths (4, 5) as well as a ring (6) in which the acoustic transducer (1) is embedded. The diameter of the acoustic transducer (1) is selected such that it is smaller than the diameter of the delay paths (4, 5) so that diffracted waves generated in the area of the edge of the acoustic transducer generate fewer parasitic echoes and surface waves on the boundary surfaces (7, 9) resulting in less corruption of the measured result.