Patent ID: 6976503
Filing Date: 2005-12-20
Classification: F16K,Y10T

Abstract:
1. A diagnostic system for a valve actuated by a positioner by way of a drive, wherein the valve has a sensor for detecting structure-borne noise, the diagnostic system comprising: a measurement signal evaluating device that receives from the sensor a measurement signal of the structure-borne noise, wherein the measurement signal evaluating device comprises an arithmetic logic unit that: determines a first value of a characteristic during a calibration process, wherein the first value is determined based on a first progression of the measurement signal recorded when the valve is in a closed position; determines at least one second value of the characteristic during operation of the valve, wherein the second value is determined based on at least one second progression of the measurement signal recorded when the valve is in an almost-closed position; compares the second value with the first value; and generates a status signal to indicate that no leakage diagnosis is possible if the deviation of the second value from the first value does not exceed a predefined first threshold value.