DEVICE FOR MEASURING LIQUID DENSITY OR GAS DENSITY BASED ON FREQUENCY DURATION PERIOD OF MEASUREMENT VIBRATOR FILLED WITH SAMPLE

摘要

PURPOSE: To perform accurate concentration measurement by exciting a reference vibrator in thermal contact with a measurement vibrator at a mechanical resonance frequency through a transducer and an exciter, for compensating changes and aging due to temperature. ;CONSTITUTION: A measurement vibrator 1 and a reference vibrator 2 are constructed of the same material, and a resonance frequency of the vibrator 2 is significantly different from that of the vibrator 1 (for example by factor 2). The vibrators 1 and 2 are assigned in a common casing 3, and the casing 3 contact to a facing mass body 11 by its one end part, and to an exciter (for example, a piezoelectric element) 4 by its the other and part. In addition, the vibrator 2 is in thermal contact to the vibrator 1, and through a transducer and the exciter 4, is excited at its mechanical resonance frequency, and sends out another periodical signal whose frequency agrees with the cycle of the vibrator 2 or its multiple. The changes due to temperature and aging equally act on the vibrators 1 and 2, so that, the deviation in measurement result resulting from this is compensated.;COPYRIGHT: (C)1993,JPO