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DIGITAL FLOWMETER

  • US 3,869,915 A
  • Filed: 01/23/1973
  • Issued: 03/11/1975
  • Est. Priority Date: 01/23/1973
  • Status: Expired due to Term
First Claim
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1. Ultrasonic detection apparatus for detecting a condition of a fluid in an enclosed elongated hollow conduit;

  • said apparatus comprising first and second transducer means secured to the exterior surface of said conduit and being axially spaced from one another along the axis of said conduit;

    each of said first and second transducer means being adapted to transmit to the other, and receive from the other, ultrasonic energy pulses which pass through the fluid within said conduit; and

    circuit means connected to said first and second transducer means for measuring the difference in time taken for ultrasonic energy pulses to reach said first transducer means from said second transducer means and to reach said second transducer means from said first transducer means, and for producing an output related to said difference in time; and

    clock generator means for producing a train of output pulses having a given clock frequency and counter means connected to said clock generator means;

    said circuit means being connected to said counter means and controlling said counter means to count up pulses from said clock generator means during the time taken for said ultrasonic energy pulses to travel from said first transducer means to said second transducer means, said last-mentioned time defining an up cycle, and to count down pulses from said clock generator means during the time taken for said ultrasonic energy pulses to travel from said second transducer means to said first transducer means, said last-mentioned time defining a down cycle;

    said circuit means including a counting clock means for measuring time and which has a counting clock frequency fc;

    said output related to said difference in time being related to the value F where F mfc (vm/vs) sin theta TR where F is the digitized flow of fluid in said conduit in flow units, m is a constant, vm is the flow velocity of said fluid, vs is the velocity of sound in said fluid, theta is the angle of travel of said ultrasonic energy pulses to a normal to the pipe axis as the pulses travel through said fluid, and TR is a function of vs, theta and the internal diameter of said conduit; and

    which further includes second circuit means connected to said first and second transducer means for determining the speed of sound in said fluid, and for adjusting the total number of times for counting the time taken for sound to traverse from said first to said second transducer means and from said second to said first transducer means proportionally with the velocity of sound in said fluid.

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