Monitoring of check valves in reciprocating pumps

Abstract

Techniques are described for condition monitoring of check valves in reciprocating pumps that are used to charge pressure tanks to high pressures (310 bar). During a period of several months vibration measurements were made on cylinder heads of several pumps. The vibration signals typically showed transients that are caused by the closing impacts of the check valve plates. The frequency spectrum of the transients is complicated and, due to cross-talk from neighboring cylinders, it is not possible to draw conclusions from spectral information about a particular valve’s condition. To isolate signatures from particular valves, time domain modeling and filtering techniques have been studied (e.g., Prony Series). One approach has been to model, in detail, the transient events that take place during each revolution of a pump. The goal of this analysis was to find parameters that can be extracted from the signals that show sensitivity to the changing condition of the valves. The results from different analysis techniques are discussed in the paper, and are correlated with the known condition of the valves in one of the pumps. Finally, suggestions for an implementation in a condition monitoring device are made.