| 摘要 |
PURPOSE:To correct the flow meter easily with a comparatively simple constitution, by flowing the fluid including particles such as minute bubbles in an accurate flow velocity only to the measure point. CONSTITUTION:In case that the flow velocity measure point is placed at point P and the correcting fluid is flowed in the same direction as the fluid, which should be measured, in flow velocity V0 to correcting flow path 10, where the correcting fluid including minute particles, it flowed, only for correction, the relation between Doppler shift frequency fd0 and costheta0 obtained by the flow meter is costheta0=C0. fd0/2V0; however, if temperatures and materials of fluids flowed to point P are equal to each other, theta0=theta and C0=C are true. C is the sound velocity of the fluid, and theta is the phase angle. As the result, V=V0.fd/fd0 is obtained, and further, V=C.V0.fd/(C0.fd0) is true. Consequently, in measurement of the flow velocity in the Dopper flow meter, flow path 10 is removed from point P, and the Doppler frequency is measured, and the measure result is multiplied by C.V0/(0.fd0), thus detecting accurately the flow velocity of the fluid in flow path 2. |
