To avoid discontinuation during long-term continuous operation in plants, a reliable monitoring system for the state diagnosis is strongly expected. However, occurring troubles of various facilities in a plant aren’t simple. We proposed a sophisticated estimation method to diagnosis the state for reciprocating compressors. Our monitoring system uses both the measuring data in the factory and the analytical results based on the mathematical model, which can express the dynamic behavior about the reciprocating compressor. The mathematical model has multi degrees of freedom and the model parameters are identified to estimate the state change. To realize the reliable monitoring, we have to establish estimation and diagnosis method for any change of the operation state.
In this paper, we discuss a dynamic model that is able to analyze the dynamics responses of the reciprocating compressor during operation based on the measurement data. We show that the viscous damping coefficients are rather smaller than the spring constants of the parallel elements and the only behavior in the horizontal direction is affected by the damping character. To express the vertical acceleration in time history, we examine the dependency of time histories about acceleration during operation upon the crank angle and propose modified generating forces in the connecting parts.