| 摘要 |
A densitometer of the vibrator type is disclosed wherein a spring mass system is immersed in a liquid whose density is to be determined. The system includes a pair of coaxial cylindrical masses in the form of fluid couplers having spaces which are open to the liquid. A torsion spring connects both cylindrical masses through mechanically stiff coupling means. The coupling means include a pair of high impedance transducers positioned at the shear interfaces normal to the common axis of the system, so as to take substantially the full torsional shear load between the spring and the cylindrical fluid couplers without contributing to the spring effect. The compliance of the torsion spring allows oscillatory motion of the spring mass system around its axis. An output signal having a high signal-to-noise ratio is provided at the natural resonant system frequency. The signal frequency is a measure of the density of the liquid contained in the spaces and it is substantially independent of the effect of temperature changes on the transducers. Thus, a highly sensitive and accurate densitometer is provided.
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