Patent ID: 7958786
Filing Date: 2011-06-14
Classification: G01F

Abstract:
1. A method for measuring a fluid flow with a first transducer and a second transducer comprising: transmitting a reference signal having a reference phase through the fluid flow from the first transducer to the second transducer; receiving the reference signal at the second transducer as a received reference signal; concurrent with at least a portion of transmitting the reference signal, transmitting a first counter-propagating signal having a first phase through the fluid flow from the second transducer to the first transducer; receiving the first counter-propagating signal at the first transducer as a received first counter-propagating signal; summing the received reference signal with the received first counter-propagating signal; determining a first maximum amplitude of the sum of the received reference signal and the received first counter-propagating signal; concurrent with at least a portion of transmitting the reference signal, transmitting a second counter-propagating signal having a second phase through the fluid flow from the second transducer to the first transducer; receiving the second counter-propagating signal at the first transducer as a received second counter-propagating signal; summing the received reference signal with the received second counter-propagating signal; determining a second maximum amplitude of the sum of the received reference signal and the received second counter-propagating signal; and determining a phase difference between a phase advance induced by the fluid flow on one of the received reference signal relative to the reference phase and the received first counter-propagating signal relative to the first phase and a phase delay induced on one of the received reference signal relative to the reference phase and the received first counter-propagating signal relative to the first phase based upon a ratio of the first maximum amplitude and the second maximum amplitude.