Flow Measurement Apparatus and Method

摘要

The velocity of fluids containing particles that scatter ultrasound can be measured by determining the Doppler shift of the ultrasound scattered by the particles in the fluid. Measuring fluid flow in cylindrical vessels such as blood vessels is an important use of Doppler ultrasound. This invention teaches using various configurations of cylindrical diffraction-grating transducers and cylindrical non-diffraction-grating transducers that suppress the Doppler shift from non-axial components of fluid velocity while being sensitive to the Doppler shift produced by axial velocity components. These configurations thus provide accurate measurement of the net flow down the vessel, even when the fluid flow is curved or not parallel to the vessel wall.

主权项

1. An ultrasonic transducer apparatus for measuring a velocity of a fluid containing ultrasound scatterers flowing through a lumen, the apparatus comprising:
a cylindrical non-diffraction-grating transducer adapted to be wrapped around the circumference of the lumen and coupled to a predetermined number of electrode elements for exciting an ultrasound beam perpendicular to the axis of said cylindrical non-diffraction-grating transducer; a cylindrical diffraction-grating transducer disposed in a close proximity to the cylindrical non-diffraction-grating transducer and adapted to be wrapped around the circumference of the lumen, wherein said cylindrical diffraction-grating transducer is coupled to a predetermined number of electrode elements for (1) receiving scattered signals having changing phases with respect to the ultrasound beam and (2) connecting to a circuit for determining the velocity of the fluid based on the changing phases of the received scattered signals.