METHOD AND INSTRUMENT FOR MEASURING CONCENTRATION OF GAS

Japanese Patent JP2744742

B2

PURPOSE: To accurately measure the concentration of a gas even when a deterioration signal is superimposed by measuring the pressure and gas concentration signal in a gas atmosphere from a gas signal obtain by removing a high-frequency component of a prescribed or higher value from a detecting signal.
CONSTITUTION: A fundamental and second harmonic detecting signals Ps (ω) and Ps (2ω) are obtained by making the phase of a signal detected 8 from a gas measuring cell 7 sensitive by means of lock-in amplifiers 13 and 14 and Ps (2ω)/Ps (ω) is calculated 15, with the calculated result inputted to the Y-axis of an X-Y recorder 20. Regarding a high-concentration gas, the pressure of the gas is found from extremal-value widths appearing on both sides of a crest value and a gas concentration signal is corrected for pressure. Regarding a low-concentration gas, on the other hand, the pressure and gas concentration signals of the gas atmosphere are measured from gas signals obtained after removing a high frequency of a prescribed or higher value from phase-sensitive detecting signals by resolving the detecting signals into frequency regions by inputted data to an FFT analyzer 22 and processing the signals through a low-pass filter after comparing the signals with the power spectrum density distribution of a waveform upon which no noise is superimposed.

Akihiko Ishibashi
Yasuo Yoshida
Masahiko Uchida

JP29586692A

April 28, 1998

November 05, 1992

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THE TOKYO ELECTRIC POWER COMPANY,INCORPORATED
Hitachi Cable Ltd.

G01N21/35; G01N21/3504; G01N21/39; (IPC1-7): G01N21/39; G01N21/35

JP3277945A
JP3505782A
JP6378053A

Nobuo Kinutani

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