Abstract: In a process for the monitoring and automatic early fault detection in valves, in particular intake and/or pressure valves, of an oscillating displacement pump, in particular a membrane dosing pump, it is provided that the increased operating noise produced by a leaky valve due to the back-flow of the fluid being pumped in the closed state of the valve is used as a measure for the leakiness of the valve by the generated effective signal level being monitored continuously and compared to a reference signal level formed from the operating noise of the pump with an intact valve, where, at a predefined level deviation or change due to increased operating noise, early fault detection is triggered. A device for carrying out of this process includes a corresponding measuring device, in particular in the form of a vibration acceleration sensor measuring the produced structure-borne sound as well as a comparator device.

Abstract: In a process for the monitoring of leakage in the hydraulic pressure area of a membrane pump, processing is in a manner such that the point in time (t3), at which the snifting process serving for leakage compensation is initiated, is monitored continuously and compared with a reference value (t1), where a predetermined deviation (?t1?t3) between two values (t3 and/or t1) triggers a leakage display.