Abstract: A method for detecting and localizing a valve leak in a piston machine having a shaft includes: attaching one or more vibration sensor to a valve block of the piston machine; measuring the vibrations from at least one of the vibration sensors; attaching a sensor to the piston machine where the sensor is designed to produce, directly or indirectly, an angular shaft position signal for the shaft; determining, directly or indirectly, an angular shaft position signal for the shaft; transforming vibration signals from the one or more vibration sensors into one envelope signal representing an instant vibration level; using the angular position signal for constructing window functions that pick the envelope signal in selected angular shaft sectors; using the window functions to find sector based averages of the vibration level; and comparing said averages with a critical ambient vibration level to detect and localize leaks in one or two valves.

Abstract: A method for detecting and localizing a valve leak in a piston machine having a shaft includes: attaching one or more vibration sensor to a valve block of the piston machine; measuring the vibrations from at least one of the vibration sensors; attaching a sensor to the piston machine where the sensor is designed to produce, directly or indirectly, an angular shaft position signal for the shaft; determining, directly or indirectly, an angular shaft position signal for the shaft; transforming vibration signals from the one or more vibration sensors into one envelope signal representing an instant vibration level; using the angular position signal for constructing window functions that pick the envelope signal in selected angular shaft sectors; using the window functions to find sector based averages of the vibration level; and comparing said averages with a critical ambient vibration level to detect and localize leaks in one or two valves.