DIGITAL FLOWMETER
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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Abstract
A digital flowmeter provides axially spaced transducers clamped on the exterior of a fluid conducting conduit. Sonic energy from the first transducer is applied through the pipe and into the medium and the time taken to reach the second transducer is counted. Sonic energy is then sent from the second transducer, through the medium, to the first transducer and the time taken to reach the first transducer is counted and subtracted from the first time. This difference is then displayed as a function of flow.
31 Citations
12 Claims
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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.
- 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;
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2. The detection apparatus of claim 1 wherein said first and second transducer means are mounted on the same side of said conduit, and wherein ultrasonic energy flowing between said first and second transducer means is reflected from the opposite interior surface of said conduit.
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3. The detection apparatus of claim 2 wherein said angle of reflection to the normal of said interior surface is in the range between 29* and 51*.
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4. The detection apparatus of claim 2 wherein said angle of reflection to the normal of said interior surface is about 48*.
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5. The detection apparatus of claim 1 which further includes control circuit means for controlling the sequence of said up and down cycles, whereby a given number of up cycles are initiated, followed by a corresponding number of down cycles;
- said given number of up and down cycles defining a read cycle for producing said output which will be related to the residual count in said counter at the end of said read cycle.
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6. The detection apparatus of claim 1, wherein said circuit means further includes receiver means for receiving said ultrasonic energy pulses to measure their time of transit upon the sensing of a given return signal condition, and gating means for gating said receiver means open when the instantaneous output signal level from said receiver means exceeds a given value;
- and wherein said circuit means further includes voltage zero detection means for measuring an instantaneous voltage zero in said return signal;
said voltage zero detection means being connected to pulse transmission time measuring means for measuring the time from the transmission of said ultrasonic pulses to the occurrence of the first voltage zero of said received signal after gating open said receiver means.
- and wherein said circuit means further includes voltage zero detection means for measuring an instantaneous voltage zero in said return signal;
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7. The detection apparatus of claim 6 which further includes second counter means for counting the length of time taken from the time of transmission of a pulse to the time the corresponding received signal reaches said instantaneous level;
- said second counter means being connected to said gating means and gating said receiver means open and in readiness for receipt of a pulse related to the next instantaneous zero voltage level in the return signal following said last mentioned length of time for all up-down cycles in a read cycle following the first up cycle which establishes said last mentioned length of time.
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8. Ultrasonic detection apparatus for detecting the flow of fluid in an elongated conduit;
- said apparatus comprising first and second transducer means spaced from one another in an axial direction 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 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
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 within a read cycle 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.
- said apparatus comprising first and second transducer means spaced from one another in an axial direction of said conduit;
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9. The detection apparatus of claim 8 wherein said first and second transducer means are mounted on the same side of said conduit, and wherein ultrasonic energy flowing between said first and second transducer means is reflected from the opposite interior surface of said conduit.
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10. Ultrasonic detection apparatus for detecting the flow of fluid in an elongated conduit;
- said apparatus comprising first and second transducer means spaced from one another in an axial direction 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 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; and
including 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.
- said apparatus comprising first and second transducer means spaced from one another in an axial direction of said conduit;
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11. The detection apparatus of claim 10 which further includes control circuit means for controlling the sequence of up and down cycles, whereby a given number of up cycles are initiated, followed by a corresponding number of down cycles;
- said given number of up and down cycles defining a read cycle for producing said output which will be related to the residual count in said counter at the end of said read cycle.
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12. 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; and
control circuit means for controlling the sequence of said up and down cycles, whereby a given number of up cycles are initiated, followed by a corresponding number of down cycles;
said given number of up and down cycles defining a read cycle for producing said output which will be related to the residual count in said counter at the end of said read cycle.
- 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;
Specification