Patent ID: 6508135
Filing Date: 2003-01-21
Classification: G01F,G01P

Abstract:
A liquid flow meter for directly measuring the velocity of a liquid, said liquid flow meter including:a pair of transducers arranged facing each other in a conduit through which said liquid flows: transmitter means coupled to said transducers via resistive components, said transmitter means being configured to cause said transducers to simultaneously transmit an acoustic wave packet directed for reception at the other said transducer; and a pair of receiver amplifiers having inputs each coupled to a corresponding one of said transducers and to a corresponding one of said resistive components, said receiver amplifiers being configured to detect an acoustic signal received by a corresponding one of said transducers and to determine a time difference between the two received signals, said time difference being related to the velocity of liquid within the conduit, wherein the transmitter means and said receiver amplifiers are each matched to said transducers, utilising said resistive components, to ensure substantial reciprocity to thereby substantially avoid phase and/or amplitude variations in said received signals.