Patent ID: 7664618
Filing Date: 2010-02-16
Classification: F04D,G05B

Abstract:
1. A trend monitoring and diagnostic analysis method for the failure protection and predictive maintenance of a vacuum pump running under idle and gas-loaded operation conditions alternately, comprising the steps of: sampling the time series of the state variables signals at the predetermined rate for the idle and gas-loaded operation conditions; sorting out the maximum and minimum values of the time series of the state variables from each segmented set of consecutively sampled signals being longer than the period of fluctuating state variable signal components for the idle and gas-loaded operation conditions; estimating the one set of the best-fitted model parameters of the asymptotic upper bound from the sorted maximum values of each state variable and the other set of the best-fitted model parameters of the asymptotic lower bound from the sorted minimum values of each state variable, by using a linear parametric model-based active diagnostic algorithm, for the idle and gas-loaded operation conditions; evaluating the pumping speed indicator based on a inlet pressure signal by using the in-situ estimation method whenever the transition state from the gas-loaded operation condition to the idle one is observed; storing the estimated upper and lower model parameters of the asymptotic upper and lower bounds of all considered state variables for each idle and gas-loaded operation condition and the evaluated pumping speed indicator whenever the transition state from the gas-loaded operation condition to the idle one is observed; repeating the estimation of model parameters of the upper and lower bounds of each state variable for the idle and gas-loaded operation conditions and the evaluation of the pumping speed indicator; and monitoring the variation trend from the estimated upper and lower model parameters of all considered state variables collected for the consecutive idle operation conditions and from those of all considered state variables collected for the consecutive gas-loaded operation conditions and from the consecutively collected pumping speed indicators from the repeated transitions from the gas-loaded operation state to the idle state, and diagnosing whether the vacuum pump is abnormal or not on the basis of the variation trend analysis results thereof.