Coriolis mode processing techniques
AssigneeInvensys Systems, Inc.
InventorManus P. Henry
Life of this patent
Estimating the term…
Abstract
Flowmeters are described in which a sensor signal received from a sensor that is attached to vibratable flowtube, so as to determine properties of a fluid within the flowtube, contains a drive signal component and a Coriolis mode component. The flowmeters are operable to determine drive parameters of the drive signal component, as well as Coriolis parameters of the Coriolis mode component. By analyzing the sensor signal based on the drive signal parameters, and not on the Coriolis signal parameters, the flowmeters are able to provide stable and accurate determinations of the properties of the fluid.
Claims14
A Coriolis flowmeter comprising:
- a flowtube having a fluid flowing therethrough, the flowtube being subject to a vibration, the vibration of the flowtube comprising at least a drive mode of vibration and a contaminant mode of vibration;
- a sensor for outputting an observed signal representative of the vibration of the flowtube, the observed signal including a drive mode signal corresponding to the drive mode of vibration and a contaminant mode signal corresponding to the contaminant mode of vibration;
- and,
- a transmitter for receiving the observed signal and determining a parameter of the fluid, the transmitter comprising:
- a zero-crossing detector for detecting a plurality of observed zero-crossings of the observed sensor signal;
- a frequency calculator operable to determine an observed signal frequency and an initial estimate of frequency of the contaminant mode signal, the observed signal frequency and the contaminant mode signal frequency being used to determine a parameter of fluid passing through the flowmeter.
Dependencies are inferred from the claim text.