Patent ID: 8521334
Filing Date: 2013-08-27
Classification: F15B,F16K,G05B,Y10T

Abstract:
1. A method for diagnosing an operating state of a valve arrangement for controlling a flow of a process medium through a pipeline, wherein the valve arrangement includes a valve element accommodated in a valve housing and configured to switch the flow of the process medium in accordance with a positioning control system via a pneumatic actuator having a control piston, to at least one side of which control pressure is applied in a drive chamber, and an electronic evaluation unit connected to the positioning control system and configured to monitor the operating state of the valve arrangement, wherein the method comprises: measuring in a pressure sensor, the pressure in at least one of the drive chamber and the pneumatic actuator operatively connected to the drive chamber; analyzing the measured pressure in the evaluation unit with respect to a pressure p and a pressure change dp(t) over time to determine at least one of the flow into/from the drive chamber and a ratio of a volume of the drive chamber volume to an effective opening cross section of the valve arrangement as a measure of the operating state of the valve arrangement; and