Apparatus and method for compensating a coriolis meter

• US 20050044929A1
• Filed: 07/15/2004
• Published: 03/03/2005
• Est. Priority Date: 07/15/2003
• Status: Active Grant

• Current Assignee: Expro Meters, Inc. (Umbrellastream LP, Inc.)
• Original Assignee: Cidra Sarl (Nordic Cultural & Educational Foundation)
• Inventors: Gysling, Daniel L., Curry, Patrick, Loose, Douglas H., Banach, Thomas E.
• Granted Patent: US 7,152,460 B2
• Time in Patent Office: Days
• US Class Current: 73/32.A
• CPC Class Codes: G01F 1/74 Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid
• CPC Class Codes: G01F 1/8413 means for influencing the flowmeter's motional or vibrational behaviour, e.g., conduit support or fixing means, or conduit attachments
• CPC Class Codes: G01F 1/8477 with multiple measuring conduits
• CPC Class Codes: G01F 15/024 involving digital counting
• CPC Class Codes: G01F 25/10 of flowmeters
• CPC Class Codes: G01N 2291/02818 Density, viscosity
• CPC Class Codes: G01N 9/002 using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis G01N9/34 takes precedence

Abstract

A flow measuring system is provided that provides at least one of a compensated mass flow rate measurement and a compensated density measurement. The flow measuring system includes a gas volume fraction meter in combination with a coriolis meter. The GVF meter measures acoustic pressures propagating through the fluids to measure the speed of sound α_mix propagating through the fluid to calculate at least gas volume fraction of the fluid and/or the reduced natural frequency. For determining an improved density for the coriolis meter, the calculated gas volume fraction and/or reduced frequency is provided to a processing unit. The improved density is determined using analytically derived or empirically derived density calibration models (or formulas derived therefore), which is a function of the measured natural frequency and at least one of the determined GVF, reduced frequency and speed of sound, or any combination thereof. The gas volume fraction (GVF) meter may include a sensing device having a plurality of strain-based or pressure sensors spaced axially along the pipe for measuring the acoustic pressures propagating through the flow.

Claims

1. A flow measuring system for measuring density of a fluid flowing in a pipe, the measuring system comprising:

a coriolis meter having at least one tube wherein fluid flows therethrough, the coriolis meter providing a frequency signal indicative of a natural frequency of a tube and/or phase signal indicative of a phase difference between a pair of tubes;

a flow measuring device measures the speed of sound propagating through the fluid, the measuring device providing at least one of an SOS signal indicative of the speed of sound propagating through the fluid, a GVF signal indicative of the gas volume fraction of the fluid and a reduced frequency indicative of the reduced frequency of the fluid; and

a processing unit determining a compensated mass flow rate measurement in response to at least one of the SOS signal, the GVF signal and the reduced frequency signal and the phase signal, and/or determining a compensated density measurement in response to the SOS signal, the GVF signal and the reduced frequency signal and the frequency signal.

2. The measuring system of claim 1, wherein the speed of sound measurement is used to determine a gas volumetric fraction (GVF) in the flow of the fluid.

3. The measuring system meter of claim 1, wherein the Coriolis meter comprises at least one tube having an array of sensors arranged thereon for performing the speed of sound measurement on the fluid flowing therein.

4. The measuring system of claim 3, wherein the array of sensors includes strain based sensors.

5. The measuring system of claim 1, wherein the Coriolis meter comprises a tube having a speed of sound sensing device arranged thereon for performing the speed of sound measurement on the fluid flowing therein.

6. The measuring system of claim 1, wherein the Coriolis meter comprises a speed of sound sensing device arranged on the pipe for performing the speed of sound measurement of the fluid flowing therein.

7. The measuring device of claim 1, wherein the tube of the coriolis is bent or straight.

8. The measuring device of claim 1 wherein processing unit determines a composition signal indicative of the density of a non-aerated portion of the fluid in response to SOS signal and the compensated density measurement.