Vibratory Flowmeter Verification Without Ramp Time
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Solution Overview
Problem
Coriolis mass flowmeters face challenges in accurately tracking changes in the Flow Calibration Factor (FCF) over time due to changes in conduit stiffness, leading to potential inaccuracies in mass flow rate and density measurements.
Innovation Solution
A method and apparatus for vibratory flowmeter verification that involves vibrating the sensor assembly with test tones without a ramp function, measuring response voltages and frequencies, applying filters to isolate responses, and generating a meter stiffness value to verify proper operation, thereby improving the accuracy and efficiency of FCF tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If test tones are applied with a ramp function to avoid frequency deviations, then measurement stability is improved, but verification time increases significantly
Solution Approach 1:
The patent applies preliminary filtering actions to the pickoff sensor signals before frequency estimation. By pre-filtering the signals with a bandpass filter centered at the excitation frequency, the system prepares the signals in advance to resist frequency deviations, allowing instant tone application without ramp functions while maintaining measurement stability.
Solution Approach 2:
The patent creates a filtered copy of the pickoff sensor signals that is synchronized with the excitation frequency. This filtered signal copy is used for frequency estimation and stiffness calculation, eliminating the need for gradual ramping while maintaining accuracy through the use of frequency-synchronized filtering.
2Measurement precision
If multiple filter coefficients are used to synchronize frequency estimates with tone frequencies, then measurement accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent changes the filter parameters dynamically based on the excitation frequency. The bandpass filter is reconfigured with center frequency and bandwidth parameters that match the current test tone frequency, allowing accurate frequency tracking without requiring an excessively large number of fixed coefficients. This adaptive parameter adjustment achieves synchronization with fewer computational resources.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for quick and precise verification of flowmeter performance, reducing the time and improving the accuracy of FCF tracking, ensuring reliable and accurate mass flow rate and density measurements by eliminating the need for ramped tones and frequency deviations.
Implementation Method 1
vibrating a sensor assembly of the vibratory flowmeter with a plurality of test tones in a vibration mode using a driver
Implementation Method 2
measuring a vibrational response of the flow conduit or conduits, and are typically located at both positions upstream and downstream of the actuator
Implementation Method 3
Filtering is applied to the pickoff sensor signals and current signal to isolate the response at each of the plurality of test tones
Data Source
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AI summary
A meter verification method for a vibratory flowmeter (5) is provided, comprising vibrating a sensor assembly (10) of the vibratory flowmeter (5) with a plurality of test tones in a vibration mode using a driver (180), wherein the plurality of test tones is applied substantially instantly, in the absence of a ramp function. A driver (180) current is determined, and response voltage of pickoff sensors (170L, 170R) are determined for the vibration mode. The instantaneous frequency of the pickoff sensor (170L, 170R) signals is measured, and a filter is applied to isolate the response at each of the plurality of test tones. The filter is also applied to the instantaneous frequency measurements. The same delay is applied to the frequency measurements and the response at each of the test tones. A meter stiffness value (216) is generated using the current (230) and the response voltage (231), and proper operation of the vibratory flowmeter (5) is verified using the meter stiffness value (216).