Ultrasonic system for measuring flow rate, fluid velocity, and pipe diameter based upon time periods

• US 6,158,288 A
• Filed: 01/28/1999
• Issued: 12/12/2000
• Est. Priority Date: 01/28/1999
• Status: Expired due to Fees

• Current Assignee: Ping Chee
• Original Assignee: Dolphin Technology, Inc. (ITT, Inc.)
• Inventors: Smith, Milton O.
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): PATEL, JAGDISH C
• Application Number:
  US09/239,160
• Time in Patent Office: 684 Days
• Field of Search: 73/861.18, 73/861.25, 73/861.26, 73/861.27, 73/861.28, 73/861.29, 73/861.31, 73/861.04, 73/861
• US Class Current: 73/861.25
• CPC Class Codes: G01F 1/662 Constructional details
• CPC Class Codes: G01F 1/667 Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
• CPC Class Codes: G01F 1/668 Compensating or correcting for variations in velocity of sound
• CPC Class Codes: G01F 25/10 of flowmeters
• CPC Class Codes: G01P 5/245 by measuring transit time of acoustical waves measuring propagation velocity of acoustical waves per se G01H5/00

Abstract

An ultrasonic flowmeter using ultrasonic pulses transmitted within a pipe containing flowing fluid determines values, including flow rate or fluid velocity of the flowing fluid. The ultrasonic flowmeter transmits trains of ultrasonic pulses having velocity components either in the upstream or downstream direction. The ultrasonic flowmeter includes the transducer placed downstream external to the pipe and a transducer placed upstream external to the pipe. Time measurements are made to determine a time, T_U, required for a pulse train to travel from the downstream transducer to the upstream transducer and the time, T_D, required for a pulse train to travel from the upstream transducer to the downstream transducer. The ultrasonic flowmeter is configured to have consistent triggering of the pulses of the pulse train to reduce error. Also, the electronics are simplified to allow for lower timing resolution requirements. Once T_U and T_D are determined, a series of validation filters, parameter filters, coarse flow filters, and refined flow rate filters are used to determine flow measurement. Alternatively, fluid velocity filters are used. Also, diameter filters are used to determine the current interior diameter of the pipe. All measurements are made noninvasively. The system and method includes determining coefficients for the various filters to account for variability in dimensions, parameters and conditions involved.

Claims

1. An ultrasonic meter, attachable to a pipe having a longitudinal axis and fluid therein, the ultrasonic meter comprising:

an upstream transducer configured for external attachment to the pipe, the upstream transducer configured to receive upstream electrical signals and upstream ultrasonic pulses, to transmit upstream ultrasonic pulses based on the upstream received electrical signals by the upstream transducer and to transmit upstream electrical signals based on the upstream received ultrasonic pulses by the upstream transducer;

a downstream transducer configured for external attachment to the pipe at a location displaced from the upstream transducer along the longitudinal axis of the pipe, the downstream transducer configured to receive downstream electrical signals and downstream ultrasonic pulses, to transmit downstream ultrasonic pulses based on the downstream received electrical signals by the downstream transducer and to transmit downstream electrical signals based on the downstream received ultrasonic pulses by the downstream transducer;

a multiplexor electrically linked to the upstream transducer and the downstream transducer, configured to receive the upstream transmitted electrical signals from the upstream transducer, to receive the downstream transmitted electrical signals from the downstream transducer, and to receive a multiplexor control signal, the multiplexor configured to selectively block or pass either one or both of the upstream transmitted electrical signals received from the upstream transducer and the downstream transmitted electrical signals received from the downstream transducer based on the multiplexor control signal;

a logic switch electrically linked to the upstream transducer, the downstream transducer, and the multiplexor, the logic switch configured to receive the upstream transmitted electrical signals passed by the multiplexor, the downstream transmitted electrical signals passed by the multiplexor, and a logic switch control signal, and to selectively pass the upstream transmitted electrical signals as the downstream received electrical signals to the downstream transducer and to selectively pass the downstream transmitted electrical signals as the upstream received electrical signals to the upstream transducer, according to the received logic switch control signal; and

a processor electrically coupled to the logic switch and the multiplexor, the processor configured to transmit the logic switch control signal to the logic switch, and to transmit the multiplexor control signal to the multiplexor.

2. The ultrasonic meter of claim 1, further including:

a high voltage converter electrically linked to the logic switch and the upstream transducer and the downstream transducer, the high voltage converter configured to convert the upstream transmitted electrical signals and the downstream transmitted electrical signals passed by the logic switch to the upstream transducer and the downstream transducer by increasing voltage levels of the upstream transmitted electrical signals and the downstream transmitted electrical signals.

3. The ultrasonic meter of claim 1, further including:

an amplifier electrically coupled to the multiplexor, the amplifier configured to amplify signal levels of the upstream transmitted electrical signals and the downstream transmitted electrical signals passed by the multiplexor; and

a comparator electrically coupled to the amplifier and the logic switch, the comparator configured to selectively pass the upstream transmitted electrical signals and the downstream transmitted electrical signals amplified by the amplifier to the logic switch or block the upstream transmitted electrical signals and the downstream transmitted electrical signals amplified by the amplifier based on the signal levels of the upstream transmitted electrical signals and the downstream transmitted electrical signals relative to a threshold value.

4. The ultrasonic meter of claim 1 wherein the logic switch is further configured to selectively pass a subsequent one of the upstream transmitted electrical signals after a first predetermined time period expires, and to selectively pass a subsequent one of the downstream transmitted electrical signals after a second predetermined time period expires, the first predetermined time period commencing when a previous one of the upstream transmitted electrical signals has been passed by the logic switch, the second predetermined time period commencing when a previous one of the downstream transmitted electrical signals has been passed by the logic switch, the logic switch configured to block the upstream transmitted electrical signals during the first predetermined time period and to block the downstream transmitted electrical signals during the second predetermined time period.

5. The ultrasonic meter of claim 1 wherein the processor includes a timer and a counter, the processor configured to transmit a electrical signal to the logic switch and to start the timer based on transmission of the electrical signal, the counter configured to count the upstream transmitted electrical signals and the downstream transmitted electrical signals passed by the multiplexor to the logic switch, the processor configured to send the multiplexor control signal to the multiplexor to block at least one of the upstream transmitted electrical signals and the downstream transmitted electrical signals based on a value of the count of the counter, the processor configured to stop the timer based on the value of the count of the counter, the processor configured to record time values of the timer, the processor configured to determine one or more of a flow rate of the fluid, velocity of the fluid, and diameter of the pipe based upon the recorded time values.

6. The ultrasonic meter of claim 1 wherein the upstream received ultrasonic pulses are the downstream transmitted ultrasonic pulses and the downstream received ultrasonic pulses are the upstream transmitted ultrasonic pulses.

7. An ultrasonic meter usable with a pipe having a longitudinal axis and fluid contained therein, comprising:

an upstream transducer configured for external attachment to the pipe, the upstream transducer configured to receive an ultrasonic pulse and an electrical signal, to generate a plurality of upstream electrical signals each having a voltage level and each in response to the received upstream ultrasonic pulse, the upstream transducer further configured to generate a plurality of upstream ultrasonic pulses each in response to the received upstream electrical signal;

a downstream transducer configured for external attachment to the pipe, at a location displaced from the upstream transducer along the longitudinal axis of the pipe, the downstream transducer configured to receive an ultrasonic pulse, and an electrical signal, to generate a plurality of downstream electrical signals each having a voltage level and each in response to the received downstream ultrasonic pulse, the downstream transducer further configured to generate a plurality of downstream ultrasonic pulses each in response to the received downstream electrical signal;

a comparator electrically coupled to the upstream transducer and the downstream transducer, the comparator configured to receive the plurality of upstream generated electrical signals and the plurality of downstream generated electrical signals and to pass or to block each of the upstream generated electrical signals and each of the downstream generated electrical signals based on the voltage levels of each of the upstream generated electrical signals and each of the downstream generated electrical signals relative to a threshold value; and

a logic switch electrically coupled to the comparator, the logic switch configured to receive each of the upstream generated electrical signals and each of the downstream generated electrical signals passed by the comparator, the logic switch configured to route each of the upstream generated electrical signals and each of the downstream generated electrical signals passed by the comparator to one of the upstream transducer and the downstream transducer for transmission of an ultrasonic pulse or to block each of the upstream generated electrical signals and each of the downstream generated electrical signals based on time elapsed from when one of the upstream generated electrical signals and the downstream generated electrical signals was previously received by the logic switch.

8. The ultrasonic meter of claim 7, further comprising:

a processor electrically coupled to the comparator, the processor being configured to transmit the threshold value to the comparator.

9. The ultrasonic meter of claim 7, further comprising:

a processor electrically coupled to the logic switch, the processor configured to count each of the upstream generated electrical signals passed by the comparator and each of the downstream generated electrical signals passed by the comparator to determine a count, to generate logic switch control signals based on the count, and to transmit the logic switch control signals to the logic switch, the logic switch further configured to route or block each of the upstream generated electrical signals passed by the comparator and each of the downstream generated electrical signals passed by the comparator based on the logic switch control signals.

10. The ultrasonic meter of claim 7, further comprising:

a processor electrically coupled to the logic switch, the processor having a timer and a counter configured to count each of the upstream generated electrical signals and each of the downstream generated electrical signals passed by the comparator, the processor configured to use the timer and counter to determine one or more time periods associated with one or more counts of the upstream generated electrical signals and the downstream generated electrical signals passed by the comparator, the processor configured to determine at least one of a flow rate of the fluid, velocity of the fluid, and diameter of the pipe based on the determined time periods.

11. An ultrasonic meter, attachable to a pipe having a longitudinal axis and containing fluid thereon the ultrasonic meter comprising:

an upstream transducer externally mountable on the pipe, the upstream transducer configured to receive ultrasonic pulses and electrical signals, to generate upstream ultrasonic pulses based on the upstream received electrical signals and to generate upstream electrical signals based on the upstream received ultrasonic pulses;

a downstream transducer externally mountable on the pipe at a location displaced from the upstream transducer along the longitudinal axis of the pipe, the downstream transducer configured to receive ultrasonic pulses and electrical signals, to generate downstream ultrasonic pulses based on the downstream received electrical signals and to generate downstream electrical signals based on the downstream received ultrasonic pulses;

a logic switch electrically coupled to the upstream transducer and the downstream transducer, the logic switch configured to receive one or more of the upstream generated electrical signals, one or more of the downstream generated electrical signals, and a logic switch control signal, and to selectively block or pass each of the one or more upstream generated electrical signals and the one or more downstream generated electrical signals to one of the upstream transducer and the downstream transducer according to the logic switch control signal; and

a processor electrically coupled to the logic switch, the processor configured to transmit the logic switch control signal to the logic switch, the processor having a timer and a counter, the processor configured to use the timer and counter to determine a time period, T_U, associated with a number of the downstream generated ultrasonic pulses received by the upstream transducer, the processor configured to use the timer and counter to determine a time period, T_D, associated with a number of the upstream generated ultrasonic pulses received by the downstream transducer, the processor configured to determine at least one of a flow rate of the fluid, velocity of the fluid, and diameter of the pipe based on the time period T_U and the time period T_D.

12. A method of measurement of a fluid contained within a pipe, comprising the steps of:

receiving a first electrical signal at a first transducer;

transmitting a first ultrasonic pulse through the fluid from the first transducer upon receipt by the first transducer of the first electrical signal;

determining a first count associated with the first electrical signal received by the first transducer;

receiving the first ultrasonic pulse at a second transducer;

transmitting a second electrical signal from the second transducer upon receipt by the second transducer of the first ultrasonic pulse;

selectively blocking the second electrical signal based upon the first count or passing the second electrical signal to the first transducer based upon the first count;

receiving a third electrical signal at the second transducer;

transmitting a second ultrasonic pulse through the fluid from the second transducer upon receipt by the second transducer of the third electrical signal;

determining a second count associated with the third electrical signal received by the second transducer;

receiving the second ultrasonic pulse at the first transducer;

transmitting a fourth electrical signal from the first transducer upon receipt by the first transducer of the second ultrasonic pulse;

selectively blocking the fourth electrical signal based upon the second count or passing the fourth electrical signal to the second transducer based upon the second count;

determining a first time period value associated with the first count and a second time period value associated with the second count; and

determining at least one of a flow rate of the fluid, velocity of the fluid, and diameter of the pipe based upon the first time period value and the second time period value.