US 6,981,424 B2
Correcting for two-phase flow in a digital flowmeter
Manus P. Henry, Oxford (United Kingdom); and Maria Jesus De La Fuente, Valladolid (Spain)
Assigned to Invensys Systems, Inc., Foxboro, Mass. (US)
Filed on Apr. 26, 2004, as Appl. No. 10/831,228.
Application 10/831228 is a continuation of application No. 10/339623, filed on Jan. 10, 2003, granted, now 6,758,102.
Application 10/339623 is a continuation of application No. 09/815273, filed on Mar. 23, 2001, granted, now 6,505,519.
Application 09/815273 is a continuation of application No. 09/716644, filed on Nov. 21, 2000, abandoned.
Claims priority of provisional application 60/191465, filed on Mar. 23, 2000.
Prior Publication US 2004/0206189 A1, Oct. 21, 2004
Int. Cl. G01F 1/78 (2006.01)
U.S. Cl. 73—861.356 23 Claims
OG exemplary drawing
 
1. A flow measurement system comprising:
an input module operable to receive an analog sensor signal from a sensor connected to a vibratable flowtube, the analog sensor signal related to a process fluid through the flowtube, wherein the process fluid includes a liquid medium and a gas;
a signal processing system operable to determine sensor signal characteristics from a digitized version of the sensor signal, and further operable to determine drive signal characteristics for a drive signal to be applied to the flowtube such that a drive phase of the drive signal substantially matches a sensor phase of the analog sensor signal;
a measurement system operable to determine a property of the process fluid, based on the sensor signal characteristics;
an output module operable to output the drive signal to the flowtube to maintain an oscillation of the flowtube while the process fluid is contained therein; and
a correction system that is operable to receive the property from the measurement system and determine a corrected property that takes into account an adverse effect of the gas in the determining of the property by the measurement system.