Method for measuring flow of fluid moving in pipe or groove-like flow passage

• US 6,907,792 B2
• Filed: 11/13/2002
• Issued: 06/21/2005
• Est. Priority Date: 11/13/2001
• Status: Expired due to Fees

• Current Assignee: Baxter International Inc.
• Original Assignee: Baxter International Inc.
• Inventors: Ohnishi, Kazumasa
• Primary Examiner(s): Patel, Harshad
• Assistant Examiner(s): Mack, Corey D.
• Application Number:
  US10/466,068
• Publication Number:
  US 20040050176A1
• Time in Patent Office: 951 Days
• Field of Search: 738/612.7, 738/612.6, 738/612.9, 738/613.54, 738/613.55, 738/613.56, 738/613.57, 738/611.8, 738/61
• US Class Current: 73/861.27
• CPC Class Codes: G01F 1/66 by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
• CPC Class Codes: G01F 1/662 Constructional details
• CPC Class Codes: G01F 1/8422 exciters
• CPC Class Codes: G01F 1/8427 detectors
• CPC Class Codes: G01F 1/849 having straight measuring conduits

Abstract

A flow rate of fluid moving within a tube having a small diameter can be measured by the steps of: preparing a structure that has first and second oscillation wave generating-detecting means on a surface of a wall along the conduit; moving the fluid in the conduit; generating an oscillation wave in the first oscillation wave generating-detecting means, applying the wave onto the wall, and measuring a period of time required for transmitting the generated oscillation wave to the second oscillation wave generating-detecting means within the wall; generating an oscillation wave in the second oscillation wave generating-detecting means, applying the wave onto the wall, and measuring a period of time required for transmitting the generated oscillation wave to the first oscillation wave generating-detecting means in the wall; and comparing a difference of the periods of time of transmission and separately prepared calibration data.

Claims

1. A method for measuring a flow rate of a fluid moving in a conduit which comprises the steps of:

(1) preparing a structure that comprises a conduit in the form of tube or channel defined by a wall, and an oscillation wave-generating means and an oscillation wave-detecting means which are arranged on an outer or inner surface of the wall along the conduit;

(2) causing movement of the fluid in the conduit;

(3) generating an oscillation wave in the oscillation wave-generating means and applying the wave onto the wall;

(4) measuring a period of time required for transmitting the generated oscillation wave to the oscillation wave-detecting means in the wall which oscillates in conjunction with the fluid moving with oscillation;

(5) preparing calibration data indicating a relationship between a flow rate of the fluid and a period of time for transmission of the oscillation wave which are obtained by the steps of moving the fluid employed in the step (2) above or an equivalent fluid thereof in the conduit of the structure prepared in the step (1) above or an equivalent structure thereof at a known rate and performing the measurement in the steps (3) to (4) above; and

(6) determining a flow rate of the fluid moving in the step (2), by comparing the period of time of transmission measured in the step (4) above and the calibration data prepared in the step (5) above.

2. The measuring method of claim 1, in which the oscillation wave-generating means comprises a transducer and an oscillation direction-controlling element, and the oscillation wave generated by the transducer is applied perpendicularly onto the wall.

3. The measuring method of claim 1, in which the wall of the conduit comprises resinous material, metallic material or ceramic material.

4. The measuring method of claim 1, in which the conduit is in the form of a tube having an inner diameter of 0.1 to 10 mm.

5. A method for measuring a flow rate of a fluid moving in a conduit which comprises the steps of:

(1) preparing a structure that comprises a conduit in the form of tube or channel defined by a wall, and an oscillation wave-generating means, a first oscillation wave-detecting means and a second oscillation wave-detecting means which are arranged on an outer or inner surface of the wall along the conduit;

(2) causing movement of the fluid in the conduit;

(3) generating an oscillation wave in the oscillation wave-generating means and applying the wave onto the wall;

(4) measuring a period from the time when the generated oscillation wave is received by the first oscillation wave-detecting means to the time when the oscillation wave is received by the second oscillation wave-detecting means, the oscillation waves being transmitted in the wall which oscillates in conjunction with the fluid moving with oscillation;

(5) preparing calibration data indicating a relationship between a flow rate of the fluid and a period of time for transmission of the oscillation wave which are obtained by the steps of moving the fluid employed in the step (2) above or an equivalent fluid thereof in the conduit of the structure prepared in the step (1) above or an equivalent structure thereof at a known rate and performing the measurement in the steps (3) to (4) above; and

(6) determining a flow rate of the fluid moving in the step (2), by comparing the period of time of transmission measured in the step (4) above and the calibration data prepared in the step (5) above.

6. The measuring method of claim 5, in which the oscillation wave-generating means comprises a transducer and an oscillation direction-controlling element, and the oscillation wave generated by the transducer is applied perpendicularly onto the wall.

7. The measuring method of claim 5, in which the wall of the conduit comprises resinous material, metallic material or ceramic material.

8. The measuring method of claim 5, in which the conduit is in the form of a tube having an inner diameter of 0.1 to 10 mm.

9. A method for measuring a flow rate of a fluid moving in a conduit which comprises the steps of:

(1) preparing a structure that comprises a conduit in the form of tube or channel defined by a wall and, a first oscillation wave generating-detecting means and a second oscillation wave generating-detecting means which are arranged on an outer or inner surface of the wall along the conduit;

(2) causing movement of the fluid in the conduit;

(3) generating an oscillation wave in the first oscillation wave generating-detecting means and applying the wave onto the wall;

(4) measuring a period of time required for transmitting the generated oscillation wave to the second oscillation wave generating-detecting means in the wall which oscillates in conjunction with the fluid moving with oscillation;

(5) generating an oscillation wave in the second oscillation wave generating-detecting means and applying the wave onto the wall;

(6) measuring a period of time required for transmitting the generated oscillation wave to the first oscillation wave generating-detecting means in the wall which oscillates in conjunction with the fluid moving with oscillation;

(7) calculating a difference between the period of time measured in the step (4) above and the period of time measured in the step (6) above;

(8) preparing calibration data indicating a relationship between a flow rate of the fluid and a difference of period of time for transmission of the oscillation wave which are obtained by the steps of moving the fluid employed in the step (2) above or an equivalent fluid thereof in the conduit of the structure prepared in the step (1) above or an equivalent structure thereof at a known rate, performing the measurements of period of times as in the steps (3) to (4) and the steps (5) to (6), and calculating a deference of the period of times in the manner as described in the step (7) above; and

(9) determining a flow rate of the fluid moving in the step (2), by comparing the difference of period of time of transmission obtained in the step (7) above and the calibration data prepared in the step (8) above.

10. The measuring method of claim 9, in which each of the oscillation wave generating-detecting means comprises a transducer and an oscillation direction-controlling element, and the oscillation wave generated by the transducer is applied perpendicularly onto the wall.

11. The measuring method of claim 9, in which the wall of the conduit comprises resinous material, metallic material or ceramic material.

12. The measuring method of claim 9, in which the conduit is in the form of a tube having an inner diameter of 0.1 to 10 mm.

13. A method for measuring a flow rate of a fluid moving in a conduit which comprises the steps of:

(1) preparing a structure that comprises a conduit in the form of tube or channel defined by a wall, and a first oscillation wave-detecting means and a second oscillation wave-detecting means which are arranged on an outer or inner surface of the wall along the conduit, and an oscillation wave-generating means provided between the two oscillation wave-detecting means;

(2) causing movement of the fluid in the conduit;

(3) generating an oscillation wave in the oscillation wave-generating means and applying the wave onto the wall;

(4) measuring a period of time required for transmitting the generated oscillation wave to the first oscillation wave-detecting means in the wall which oscillates in conjunction with the fluid moving with oscillation and measuring a period of time required for transmitting the generated oscillation wave to the second oscillation wave-detecting means in the wall which oscillates in conjunction with the fluid moving with oscillation;

(5) calculating a difference between the period of time required for transmission of the oscillation wave to the first oscillation wave-detecting means and the period of time required for transmission of the oscillation wave to the second oscillation wave-detecting means which are measured in the step (4) above;

(6) preparing calibration data indicating a relationship between a flow rate of the fluid and a difference of period of time for transmission of the oscillation wave which are obtained by the steps of moving the fluid employed in the step (2) above or an equivalent fluid thereof in the conduit of the structure prepared in the step (1) above or an equivalent structure thereof at a known rate, performing the measurements of period of times in the steps (3) to (4) and calculating a deference of the period of times in the same manner as in the step (5) above; and

(7) determining a flow rate of the fluid moving in the step (2), by comparing the difference of period of time of transmission obtained in the step (5) above and the calibration data obtained in the step (6) above.

14. The measuring method of claim 13, in which the oscillation wave-generating means comprises a transducer and an oscillation direction-controlling element, and the oscillation wave generated by the transducer is applied perpendicularly onto the wall.

15. The measuring method of claim 13, in which the wall of the conduit comprises resinous material, metallic material or ceramic material.

16. The measuring method of claim 13, in which the conduit is in the form of a tube having an inner diameter of 0.1 to 10 mm.

17. A method for measuring a flow rate of a fluid moving in a conduit which comprises the steps of:

(1) preparing a structure that comprises a conduit in the form of tube or channel defined by a wall, and a first oscillation wave-generating means and a second oscillation wave-generating means which are arranged on an outer or inner surface of the wall along the conduit, and a first oscillation wave-detecting means and a second oscillation wave-detecting means which are provided between the two oscillation wave-generating means;

(2) causing movement of the fluid in the conduit;

(3) generating an oscillation wave in the first oscillation wave generating means and applying the wave onto the wall;

(4) measuring a period from the time when the generated oscillation wave is received by the first oscillation wave-detecting means to the time when the oscillation wave is received by the second oscillation wave-detecting means, the oscillation waves being transmitted in the wall which oscillates in conjunction with the fluid moving with oscillation;

(5) generating an oscillation wave in the second oscillation wave generating means and applying the wave onto the wall;

(6) measuring a period from the time when the generated oscillation wave is received by the second oscillation wave-detecting means to the time when the oscillation wave is received by the first oscillation wave-detecting means, the oscillation waves being transmitted in the wall which oscillates in conjunction with the fluid moving with oscillation;

(7) calculating a difference between the period of time measured in the step (4) above and the period of time measured in the step (6) above;

(8) preparing calibration data indicating a relationship between a flow rate of the fluid and a difference of period of time for transmission of the oscillation wave which are obtained by the steps of moving the fluid employed in the step (2) above or an equivalent fluid thereof in the conduit of the structure prepared in the step (1) above or an equivalent structure thereof at a known rate, performing the measurements of period of times in the steps (3) to (4) and the steps (5) to (6), and calculating a deference of the period of times in the manner as described in the step (7) above; and

(9) determining a flow rate of the fluid in the step (2), by comparing the difference of period of time of transmission obtained in the step (7) above and the calibration data prepared in the step (8) above.

18. The measuring method of claim 17, in which the oscillation wave-generating means comprises a transducer and an oscillation direction-controlling element and the oscillation wave generated by the transducer is applied perpendicularly onto the wall.

19. The measuring method of claim 17, in which the wall of the conduit comprises resinous material, metallic material or ceramic material.

20. The measuring method of claim 17, in which the conduit is in the form of a tube having an inner diameter of 0.1 to 10 mm.