| Abstract | An ultrasonic transducer apparatus of variable frequency including a
diffracting structure adapted for emitting and receiving a plurality of
diffracted ultrasonic beams of calculable different angles for determining
the velocity of a fluid flowing through a lumen, and flow volume. Velocity
and flow volume are determined from at least two equations in the two
unknowns of the velocity, and the angle between the ultrasonic transducer
apparatus and the direction of the fluid flow, and from a determination of
the diameter of the lumen. |
