Patent ID: 6595071
Filing Date: 2003-07-22
Classification: A61B,G01F,H03L

Abstract:
An apparatus for estimating fluid flow in a conduit, the apparatus comprising:a probe adapted to be positioned outside a circumference of the conduit, the probe including a first transducer and a second transducer arranged to form a first transmission path through the conduit, and a third transducer and a fourth transducer arranged to form a second transmission path through the conduit, wherein the first transmission path and the second transmission path have a predetermined orientation used to estimate the fluid flow, and wherein an error in positioning the probe introduces an error angle that affects fluid flow estimates; a control circuit for use to transmit ultrasonic energy along the first transmission path between the first and second transducers, and along the second transmission path between the third and fourth transducers; a plurality of receivers, wherein each of the plurality of receivers is coupled to one of the at least four transducers to receive a signal representative of received ultrasonic energy that has been time shifted by the fluid flow in the conduit; and a processing circuit, communicatively coupled to the plurality of receivers, to determine a first flow measurement based on the ultrasonic energy received by the first and second transducers along the first transmission path, to determine a second flow measurement based on the ultrasonic energy received by the third and fourth transducers along the second transmission path, to estimate the error angle based on a relationship between the first and second flow measurements, and to compensate for the estimated error angle in fluid flow estimates.