Capacitance meter
First Claim
1. A method for determining a flow property of a fluid flowing through a conduit provided with a capacitance meter comprising an annular capacitance sensor, wherein the annular capacitance sensor comprises at least three sensor electrodes, which sensor electrodes are arranged around the circumference of the conduit, the method comprising the steps of:
- (a) selecting, for the annular capacitance sensor, a set of measurement capacitors, wherein a measurement capacitor is formed by two measurement electrodes, and wherein a measurement electrode consists either of a single sensor electrode or of at least two interconnected sensor electrodes;
(b) measuring a capacitance of each measurement capacitor, characterized in that the annular capacitance sensor forms an upstream annular capacitance sensor, and in that the capacitance meter further comprises a downstream annular capacitance sensor provided with at least three sensor electrodes, which sensor electrodes are arranged around the circumference of the conduit, wherein the method further comprises the steps of (c) selecting, for the downstream annular capacitance sensor, a set of measurement capacitors;
(d) measuring at several moments during a time interval a capacitance of each measurement capacitor of each annular capacitance sensor;
(e) determining cross correlations between capacitances measured during the time interval at the upstream annular capacitance sensor and capacitances measured during the time interval at the downstream annular capacitance sensor; and
(f) determining the flow property from the cross correlations.
1 Assignment
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Accused Products
Abstract
A method for determining a flow property of a fluid flowing through a conduit (1) provided with a capacitance meter comprising an upstream and a downstream annular capacitance sensor (2a, 2b), wherein each annular capacitance sensor comprises at least three sensor electrodes (11a-13a, 11b-13b), which sensor electrodes are arranged around the circumference of the conduit, the method comprising selecting, for each annular capacitance sensor, a set of measurement capacitors, wherein a measurement capacitor is formed by two measurement electrodes, and wherein a measurement electrode consists either of a single sensor electrode or of at least two interconnected sensor electrodes; measuring at several moments during a time interval a capacitance of each measurement capacitor of each annular capacitance sensor (2a, 2b); determining cross correlations between capacitances measured during the time interval at the upstream annular capacitance sensor (2a) and capacitances measured during the time interval at the downstream annular capacitance sensor (2b); and determining the flow property from the cross correlations.
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Citations
14 Claims
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1. A method for determining a flow property of a fluid flowing through a conduit provided with a capacitance meter comprising an annular capacitance sensor, wherein the annular capacitance sensor comprises at least three sensor electrodes, which sensor electrodes are arranged around the circumference of the conduit, the method comprising the steps of:
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(a) selecting, for the annular capacitance sensor, a set of measurement capacitors, wherein a measurement capacitor is formed by two measurement electrodes, and wherein a measurement electrode consists either of a single sensor electrode or of at least two interconnected sensor electrodes;
(b) measuring a capacitance of each measurement capacitor, characterized in that the annular capacitance sensor forms an upstream annular capacitance sensor, and in that the capacitance meter further comprises a downstream annular capacitance sensor provided with at least three sensor electrodes, which sensor electrodes are arranged around the circumference of the conduit, wherein the method further comprises the steps of (c) selecting, for the downstream annular capacitance sensor, a set of measurement capacitors;
(d) measuring at several moments during a time interval a capacitance of each measurement capacitor of each annular capacitance sensor;
(e) determining cross correlations between capacitances measured during the time interval at the upstream annular capacitance sensor and capacitances measured during the time interval at the downstream annular capacitance sensor; and
(f) determining the flow property from the cross correlations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 13, 14)
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8. A method for providing corrected capacitances using an annular capacitance sensor for determining a dielectric property of a test fluid in a conduit, which capacitance sensor comprises at least four sensor electrodes arranged around the circumference of the conduit, the method comprising the steps of:
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filling the conduit with the test fluid;
selecting a set of measurement capacitors, wherein a measurement capacitor is formed by two measurement electrodes, and wherein a measurement electrode consists either of a single sensor electrode or of at least two interconnected sensor electrodes;
measuring a test capacitance of each measurement capacitor;
wherein the method further comprises the steps of interrupting the measurement at certain moments in time;
filling the conduit with a calibration fluid having a known dielectric property;
selecting a set of calibration capacitors, wherein a calibration capacitor is formed by two calibration electrodes, and wherein a calibration electrode consists either of a single sensor electrode or of at least two interconnected sensor electrodes;
measuring a calibration capacitance of each calibration capacitor; and
determining corrected capacitances from the test capacitances and the calibration capacitances by using a relationship between the calibration capacitances and the known electric property of the calibration fluid. - View Dependent Claims (9, 10, 11, 12)
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Specification