Patent ID: 6907792

Claim:
A method for measuring a flow rate of a fluid moving in a conduit which comprises the steps of: (1) preparing a structure that comprises a conduit in the form of tube or channel defined by a wall, and an oscillation wave-generating means and an oscillation wave-detecting means which are arranged on an outer or inner surface of the wall along the conduit; (2) causing movement of the fluid in the conduit; (3) generating an oscillation wave in the oscillation wave-generating means and applying the wave onto the wall; (4) measuring a period of time required for transmitting the generated oscillation wave to the oscillation wave-detecting means in the wall which oscillates in conjunction with the fluid moving with oscillation; (5) preparing calibration data indicating a relationship between a flow rate of the fluid and a period of time for transmission of the oscillation wave which are obtained by the steps of moving the fluid employed in the step (2) above or an equivalent fluid thereof in the conduit of the structure prepared in the step (1) above or an equivalent structure thereof at a known rate and performing the measurement in the steps (3) to (4) above; and (6) determining a flow rate of the fluid moving in the step (2), by comparing the period of time of transmission measured in the step (4) above and the calibration data prepared in the step (5) above.