| 摘要 |
PURPOSE:To stably measure vortex flow regardless of the temperature variations of fluid to be measured under feedback control so that the mean phase difference between transmitting wave and receiving wave may be set within the operable phase difference of a phase detector. CONSTITUTION:In a Kalman vortex flow meter for detecting the frequency of Kalman vortex by the phase difference between ultrasonic transmitting wave and receiving waves passing through fluid, the transmitting wave generated from an ultrasonic transmission vibrator 32 is received by an altrasonic wave receiver 31 and converted to a pulse waveform by a preamplifier 33. The phase difference between the transmitting and the receiving waves is detected by an exclusive OR gate 11. The mean phase difference is detected by a low pass filter composed of a resistor 11 and a capacitor 13 and compared with predetermined phase difference by a comparator 35 to thereby become predetermined phase difference by controlling a timer IC 39 oscillation frequency control terminal. |
