Patent ID: 7996183

Claim:
A performance monitoring apparatus for fluid machinery comprising: a predicted performance curve calculator, and a performance monitoring calculator, wherein the predicted performance curve calculator obtains a curve representing the relationship between pressure coefficients and flow coefficients by non-dimensional characteristics per a plural fluid control quantities from compression ratio or pressure difference, and input flow rate of the fluid machinery, the performance monitoring calculator obtains: a measured actual performance head from fluid control quantities including, suction pressure, discharge pressure, suction temperature, the compression coefficient, gas average molecular weight, and the specific heat ratio while the fluid machinery is running; a predicted performance head from a predicted performance curve, fluid control quantities, and an input flow rate; and calculates a performance degradation from the ratio of the predicted performance head to the measured actual performance head, and wherein the measured actual performance head H real is obtained from the following equation: H real =Z· 1 /β·T s /M w ·{( P d /P s ) β−1} here, P s represents suction pressure, P d represents discharge pressure, T s represents suction temperature, Z represents the compression coefficient, M w , represents gas average molecular weight, and k represents specific heat ratio, and β equals (k−1)/k.