Abstract: An flow rate measurement method and a ultrasonic flow meter is provided, which can measure a flow velocity accurately by utilizing a ultrasonic wave having a frequency by which a phase difference becomes zero. According to the flow rate measurement method, a reference ultrasonic velocity is prepared such that the fluid is in a standard condition, firstly. Then, an absolute ultrasonic velocity in the fluid and a temporary flow velocity V0 in the fluid are obtained. Then, the temporary flow velocity V0 is corrected by using the difference between the reference ultrasonic velocity and the absolute ultrasonic velocity thereby to determine an accurate flow velocity of the fluid, and to determine a flow rate of the fluid by using the accurate flow velocity and a cross section area of the conduit.

Abstract: An ultrasonic flowmeter of the present invention has a pipe (2) through which a fluid to be measured flows, and measurement portions (3) separated on the pipe by a predetermined distance along the longitudinal direction of the pipe. The measurement portions each comprises a transducer fixing member (4) having an arc shaped indentation (6) into which a part of the pipe can be fitted, and a piezoelectric transducer (5) fixed to the transducer fixing member. The pipe and the arc shaped indentation are closely fixed to each other by an adhesive (7) by fitting and pressing the pipe into the arc shaped indentation via the adhesive.

Abstract: An ultrasonic flowmeter of the present invention has a pipe (2) through which a fluid to be measured flows, and measurement portions (3) separated on the pipe by a predetermined distance along the longitudinal direction of the pipe. The measurement portions each comprises a transducer fixing member (4) having an arc shaped indentation (6) into which a part of the pipe can be fitted, and a piezoelectric transducer (5) fixed to the transducer fixing member. The pipe and the arc shaped indentation are closely fixed to each other by an adhesive (7) by fitting and pressing the pipe into the arc shaped indentation via the adhesive.

Abstract: An flow rate measurement method and a ultrasonic flow meter is provided, which can measure a flow velocity accurately by utilizing a ultrasonic wave having a frequency by which a phase difference becomes zero. According to the flow rate measurement method, a reference ultrasonic velocity is prepared such that the fluid is in a standard condition, firstly. Then, an absolute ultrasonic velocity in the fluid and a temporary flow velocity V0 in the fluid are obtained. Then, the temporary flow velocity V0 is corrected by using the difference between the reference ultrasonic velocity and the absolute ultrasonic velocity thereby to determine an accurate flow velocity of the fluid, and to determine a flow rate of the fluid by using the accurate flow velocity and a cross section area of the conduit.

Abstract: An ultrasonic flowmeter of the present invention has a pipe (2) through which a fluid to be measured flows, and measurement portions (3) separated on the pipe by a predetermined distance along the longitudinal direction of the pipe. The measurement portions each comprises a transducer fixing member (4) having an arc shaped indentation (6) into which a part of the pipe can be fitted, and a piezoelectric transducer (5) fixed to the transducer fixing member. The pipe and the arc shaped indentation are closely fixed to each other by an adhesive (7) by fitting and pressing the pipe into the arc shaped indentation via the adhesive.