Patent ID: 7406387

Claim:
An apparatus for detecting a blockage of an impulse line, the apparatus comprising: a pressure detecting unit configured to detect in time series a higher static pressure that travels through a higher pressure impulse line and generate time series data sets of the higher static pressure, the pressure detecting unit being configured to detect in time series a lower static pressure that travels through a lower pressure impulse line and generate time series data sets of the lower static pressure, the pressure detecting unit being configured to detect in time series a differential pressure between the higher and lower pressure impulse lines and generate time series data sets of the differential pressure; a first fluctuation calculating unit configured to calculate time series data sets of a differential pressure fluctuation based on the time series data sets of the differential pressure; a second fluctuation calculating unit configured to calculate time series data sets of a higher static pressure fluctuation based on the time series data sets of the higher static pressure; a third fluctuation calculating unit configured to calculate time series data sets of a lower static pressure fluctuation based on the time series data sets of the lower static pressure; a first square sum calculating unit configured to calculate the square sum of the time series data sets of the differential pressure fluctuation; a second square sum calculating unit configured to calculate the square sum of the time series data sets of the higher static pressure fluctuation; a third square sum calculating unit configured to calculate the square sum of the time series data sets of the lower static pressure fluctuation; a correlation coefficient calculating unit configured to calculate a first correlation coefficient based on the time series data sets of the differential pressure fluctuation, the time series data sets of the higher static pressure fluctuation, the square sum of the time series data sets of the differential pressure fluctuation, and the square sum of the time series data sets of the higher static pressure fluctuation, and the correlation coefficient calculating unit being configured to calculate a second correlation coefficient based on the time series data sets of the differential pressure fluctuation, the time series data sets of the lower static pressure fluctuation, the square sum of the time series data sets of the differential pressure fluctuation, and the square sum of the time series data sets of the lower static pressure fluctuation; an intermediate variable calculating unit configured to calculate an intermediate variable based on the first and second correlation coefficients; a blockage rate calculating unit configured to calculate a blockage rate based on the intermediate variable; and a determination unit configured to determine a blockage of each of the higher and lower pressure impulse lines with reference to the blockage rate.