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.