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Acoustic flowmeter

  • US 4,442,719 A
  • Filed: 01/11/1982
  • Issued: 04/17/1984
  • Est. Priority Date: 01/11/1982
  • Status: Expired due to Fees
First Claim
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1. An improvement in a monitoring circuit for an acoustic flowmeter of the type including a pair of ultrasonic transceivers at facing, longitudinally spaced locations along a conduit for producing alternating electrical output signals, each in response to the other, said electrical signals differing in phase by an amount corresponding to the rate of fluid flow in said conduit, oscillator means for feeding a predetermined alternating electrical input signal to said transceivers, said monitoring circuit being coupled to said transceivers for receiving the output signals produced thereby and for producing responsive output signals which correspond to the rate of fluid flow, the improvement comprising:

  • a pair of phase responsive circuit means responsive respectively to the two transceivers output signals for producing pairs of pulse signals having a phase difference therebetween which corresponds in a predetermined fashion to the phase difference between said output signals from the respective transceivers, both of said phase responsive circuit means including phase shifting means for producing a pair of phase-shifted pulse signals having a predetermined minimum phase difference therebetween, even in response to a zero phase difference between the transceiver output signals, comparing means responsive to said pairs of pulse signals for producing a gating signal having a duration which corresponds to the difference in phase between said pairs of pulse signals and gating means coupled to said oscillator means and responsive to said gating signal for gating through a portion of said predetermined alternating signal corresponding in a predetermined fashion to the rate of fluid flow through said conduit means.

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