Passive acoustic method of measuring the effective internal diameter of a pipe containing flowing fluids

• US 5,756,898 A
• Filed: 12/18/1995
• Issued: 05/26/1998
• Est. Priority Date: 06/27/1994
• Status: Expired due to Fees

• Current Assignee: Texaco Incorporated (Chevron Corp.)
• Original Assignee: Texaco Incorporated (Chevron Corp.)
• Inventors: Ledoux, Anna Nicole, Brown, Winthrop Kent, Diatschenko, Victor, Stoy, James Raymond
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US08/573,654
• Time in Patent Office: 890 Days
• Field of Search: 73/587, 73/592, 73/40.5 A, 73/646, 73/648, 73/584, 73/861.37, 73/861.38, 73/638, 73/637
• US Class Current: 73/592
• CPC Class Codes: G01B 17/02 for measuring thickness
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01N 2291/02854 Length, thickness
• CPC Class Codes: G01N 2291/2634 cylindrical from outside
• CPC Class Codes: G01N 29/14 using acoustic emission techniques echo of particles G01N29/046; measuring mechanical vibrations or acoustic waves in solids in general G01H1/00

Abstract

Changes in the internal diameter of a fluid handling pipes are measured by measuring the vibrational characteristics by a non-invasive, passive acoustic technique. Deviations from the normal vibrational characteristics are sensed and used to determine changes of increase or decrease in the pipe'"'"'s internal diameter.

Claims

1. A method for determining the effective internal diameter of a pipe using non-invasive passive acoustic techniques, comprising the steps of:

flowing fluid through a pipe and inducing vibration in said pipe;

providing at least one vibration sensor in intimate physical contact with said pipe and capable of detecting radial mode vibrations of said pipe in a frequency spectrum range from 2.0 kHz to 30.0 kHz;

determining a radial mode characteristic frequency and an amplitude of the characteristic frequency of vibration of said pipe in the frequency spectrum range from 2.0 kHz to 30.0 kHz;

tracking changes of said characteristic frequency and said amplitude; and

determining from said changes of said characteristic frequency and said amplitude of said radial mode vibration attributable or a function of increasing as decreasing the internal diameter of said pipe.

2. The method of claim 1 and further including the step of:

determining from a predetermined inverse functional relationship between the radial mode characteristic frequency of said pipe taken as a function of effective pipe internal diameter, the effective internal diameter of said pipe.