| 摘要 |
PURPOSE:To enable direct measurement of powder while it is held in a vessel, by detecting the electrical characteristic of a piezoelectric vibrator in a resonant state and by detecting the fluidity of the powder on the basis of a change of this electrical characteristic from a reference value. CONSTITUTION:A change in impedance by powder appears as a change in an input-output amplitude ratio. So, the frequency of an AC signal outputted from a network analyzer is scanned and a point at which a piezoelectric vibrator resonates and absorbs the AC signal is measured. The result of the measurement is determined by that the input-output amplitude ratio at the point of absorption at the time when contact with the powder is absent is A and that the input-output amplitude ratio at the point of absorption at the time when the contact with the powder is present is B. When the fluidity of the powder lowers, a viscous resistance increases and, therefore, the input-output amplitude ratio B decreases. By utilizing this, the fluidity of the powder is determined numerically by detecting the ratio of the input-output amplitude ratio B at the time of the contact with the powder to the input-output amplitude ratio A at the time of noncontact with the powder (B/A). |
