10-YEARS EXPERIENCE WITH RECIPROCATING MACHINERY VIBRATION PROTECTOR (RMP). THEORY AND FIELD RESULTS

摘要

Although overall vibration trending is an excellent tool for monitoring the health of rotating machinery, it is not generally effective for monitoring reciprocating machinery. There are several reciprocating machinery faults that do not significantly increase a machine's overall vibration level until severe damage has occurred. This paper describes improved reciprocating machinery monitoring technology based on matching filtration of vibration signal that is very sensitive to these faults in their early-stages of development and is particularly effective in monitoring reciprocating compressors. These fault conditions are primarily characterized by mechanical looseness that results in impacting within the machine and include: loose rod nuts, loose bolts, worn pins, broken parts, liquid in the cylinder, and cylinder scoring. It also introduces the Reciprocating Machinery Protector that implements these techniques. The monitoring technology based on detecting mechanical shock events in or near the machinery cylinder assembly. The amplitude of the each shock event is measured during the preset time window and is compared to a two preset thresholds. If the amplitude of the shock event not surpasses the low threshold during the time window then the monitoring out presents the normalized maximum amplitude of the shock event in previous time window. If the amplitude of the shock event surpasses one or both thresholds then the monitoring out presents the counted number of above events with the specific wait ratio. Such technology has proven very reliable in practice for identifying conditions such as looseness, crack and leakage. This paper also describes several case stories as well as a structure of monitoring sensor which realized the technology.