JP2007017157A5 - - Google Patents

Claims (11)

  An ultrasonic flowmeter in which ultrasonic transducers are arranged on the upstream side and downstream side of a flow, and the flow rate, flow rate or passage amount is obtained from the reciprocal difference in propagation time between the forward direction and the reverse direction of the ultrasonic wave. An ultrasonic flowmeter characterized by calculating a fluid temperature from a reciprocal sum of propagation times in the opposite direction and calculating a flow velocity, flow rate or passage amount at a separately determined reference temperature. An ultrasonic flowmeter in which ultrasonic transducers are arranged on the upstream and downstream sides of the flow, and the flow velocity, flow rate, or passage amount is obtained from the reciprocal difference in propagation time between the ultrasonic forward direction and the reverse direction. An ultrasonic flowmeter characterized by calculating a fluid temperature from a reciprocal sum of propagation times in the opposite direction and calculating a flow velocity, a flow rate or a passing amount . Subtract delay times such as the time to propagate through the ultrasonic transducer and the time from the head of the received wave to the zero cross of the third wave from the arrival time from when the ultrasonic wave is transmitted until the received wave is detected. claim 1 or 2 ultrasonic flow meter according is characterized in that the propagation time Te. Using temperature calculation table stored in advance, according to claim 1 or 2 or 3 ultrasonic flowmeter wherein the determination of the fluid temperature from the reciprocal sum of propagation times. 5. The ultrasonic flowmeter according to claim 4 , wherein the speed of sound is calculated from the reciprocal sum of propagation times, the type of fluid is determined by comparison with a preset speed of sound, and the temperature of the fluid is obtained . 6. The ultrasonic flowmeter according to claim 5, wherein the gas type determination value for determining the type of fluid and the data of the temperature calculation table are rewritten from the outside. The ultrasonic flowmeter according to claim 6 , wherein a distance correction coefficient between sensors for correcting the distance between the ultrasonic transducers is set from the outside. 8. The ultrasonic flowmeter according to claim 7 , wherein the measurement order in the forward direction and the reverse direction is changed for each measurement, and the reciprocal sum of the propagation times is averaged. 9. The ultrasonic flowmeter according to claim 8 , wherein the measurement interval is made random and the reciprocal sum of propagation times is averaged. 10. The ultrasonic flowmeter according to claim 9, wherein the number of data to be averaged is reduced when the flow velocity starts from zero. 11. The ultrasonic flowmeter according to claim 10, wherein the fluid temperature is calculated only when the fluid flow rate is stable.