method, device and system for detecting spring failure in a pneumatic control valve actuator, method, apparatus and system for detecting bellows failure in a control valve, method for determining a source of a leak and system for detecting spring failure on a pneumatic control valve actuator, and apparatus for identifying a source of a process control valve actuator leak

摘要

A method of determining a source of a leak in a pneumatic control valve actuator comprising: sensing travel of an actuator rod, the actuator rod being coupled to an actuator of the control valve; sensing a pressure applied to a chamber of the actuator; detecting an existence of an actuator gas leak based on sensor data of the applied actuator pressure and actuator rod travel; if a gas leak is detected, determining whether a flow switch coupled to an actuator vent indicates venting of exhaust gas through the actuator vent; if the flow switch indicates no venting of exhaust gas, generating an indication of a pneumatic tubing leak; and if the flow switch indicates venting of exhaust gas and the control valve is sensed to be moving, then generating an indication of an actuator diaphragm failure.