Method and apparatus for the ultrasonic measurement of the flow velocity of fluent media
First Claim
1. In apparatus for the measurement of fluid flow rate using ultrasonic signals, said apparatus having first and second transducers positioned in relative upstream and downstream locations in communication with the fluid to be measured for alternately transmitting said ultrasonic signals in opposite senses therebetween, the combination comprising:
- a timing generator for controlling the transmission times of said ultrasonic signals and generating a reference signal delayed with respect to each said transmission time,comparator means for generating early and late signals according to whether the received ultrasonic signals are early or late relative to each said reference signal,a first signal level generator responsive to at least some of said early and late signals for generating a first signal level related to sound speed in said fluid,logic means responsive to said comparator means and to the sense of transmission of said ultrasonic signals for generating early and late signals correlated with transmission direction upstream and downstream,a second signal level generator responsive to at least two of said early and late signals correlated with transmission direction for generating a second signal level different than said first level related to said fluid flow rate, andadder means responsive to said first and second signal levels for generating control signals related respectively to the upstream and downstream speeds of sound for controlling the timing of said timing generator.
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Abstract
Ultrasonic signals are transmitted alternately upstream and downstream in a fluent media. A reference signal timed to occur at the estimated time of arrival of the alternate signals is used to ascertain whether the actual signals arrive earlier or later than the reference signal. Control circuitry responsive to the early and late signals generates two signal levels associated with transmission direction which adjusts the time position of the reference signal until it coincides with the actual arrival times. One signal level is related to flow velocity. The other signal level is related to sound velocity in the fluent media.
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Citations
20 Claims
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1. In apparatus for the measurement of fluid flow rate using ultrasonic signals, said apparatus having first and second transducers positioned in relative upstream and downstream locations in communication with the fluid to be measured for alternately transmitting said ultrasonic signals in opposite senses therebetween, the combination comprising:
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a timing generator for controlling the transmission times of said ultrasonic signals and generating a reference signal delayed with respect to each said transmission time, comparator means for generating early and late signals according to whether the received ultrasonic signals are early or late relative to each said reference signal, a first signal level generator responsive to at least some of said early and late signals for generating a first signal level related to sound speed in said fluid, logic means responsive to said comparator means and to the sense of transmission of said ultrasonic signals for generating early and late signals correlated with transmission direction upstream and downstream, a second signal level generator responsive to at least two of said early and late signals correlated with transmission direction for generating a second signal level different than said first level related to said fluid flow rate, and adder means responsive to said first and second signal levels for generating control signals related respectively to the upstream and downstream speeds of sound for controlling the timing of said timing generator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of measuring fluid flow rate and velocity of sound propagation through a fluid utilizing at least one pair of first and second energy transducers capable of functioning as transmitters and receivers in communication with the fluid which comprises generating a transmit pulse, generating a reference pulse delayed in time to said transmit pulse, directing the transmit pulses alternately upstream and downstream of the flowing medium, receiving the transmitted pulses, comparing the phase of the received and reference pulses, generating logic signals in accordance with the early and late arrival of said received pulses relative to said reference pulses, obtaining the statistical average of all early and all late signals to provide a first signal level related to the sound speed in said medium, generating logic signals corresponding to the early and late arrival of signals relative to said reference signals correlated with the direction of transmission, obtaining the statistical average of at least one pair of early and late arrival signals to provide a second signal level related to fluid flow velocity of said medium, selectively subtracting and adding said first and second signal level for each of said upstream and downstream transmissions thereby to vary the delay time of said reference pulses for each of said upstream and downstream transmissions such that said reference pulses track the actual time of arrival of said transmitted pulses.
Specification